QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

POWER SUPPLY
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AC 100-240V Wide-range Input
Width only 82mm
Efficiency up to 93.9%
ATEX and IECEx Approved (-A1 Version)-C1 Version with Conformal Coating PC-board
150% (720W) Peak Load Capability
Safe HiccupPLUS Overload Mode
Easy Fuse Tripping due to High Overload Current
Active Power Factor Correction (PFC)
Negligible low Inrush Current Surge
Short-term Operation down to 60Vac and up to 300Vac
Full Power Between -25°C and +60°C
DC-OK Relay Contact
Quick-connect Spring-clamp Terminals
3 Year Warranty

PRODUCT DESCRIPTIONSHORT-FORM DATA

The most outstanding features of this Dimension Q-Series DIN rail
power supply are the high efficiency and the small size, which areachieved by a synchronous rectification and further novel design
details.

Output voltage
Adjustment range
Output current

With short-term peak power capability of 150% and built-in large
sized output capacitors, these features help start motors, charge
capacitors and absorb reverse energy and often allow a unit of alower wattage class to be used.

Output power

High immunity to transients and power surges as well as low
electromagnetic emission makes usage in nearly every environment
possible.
The integrated output power manager, a wide range input voltage
design and virtually no input inrush current make installation andusage simple. Diagnostics are easy due to the dry DC-OK contact, agreen DC-OK LED and red overload LED.
Unique quick-connect spring-clamp terminals allow a safe and fast
installation and a large international approval package for a variety
of applications makes this unit suitable for nearly every situation.

ORDER NUMBERS

Output ripple
Input voltage
Mains frequency
AC Input current
Power factor
AC Inrush current
Efficiency
LossesTemperature range
Derating
Hold-up time
Dimensions

DC 24V24 - 28V
20 – 17A
30 – 26A
480W
720W< 100mVpp
AC 100-240V
50-60Hz
4.56 / 2.48A
0.95 / 0.90
typ. 9 / 7A peak
92.4 / 93.9%
39.6 / 31.4W-25°C to +70°C
12W/°Ctyp. 32 / 51ms
82x124x127mm

continuous
for typ. 4s
continuous
for typ. 4s
20Hz to 20MHz±15%±6%
at 120 / 230Vac
at 120 / 230Vac
at 120 / 230Vac
at 120 / 230Vac
at 120 / 230Vac
operational+60 to +70°C
at 120 / 230Vac
WxHxD

MAIN APPROVALSPower Supply

QS20.241
QS20.241-A1
QS20.241-C1

24-28V Standard unit
ATEX approved unit
Conformal coating unit

Accessory

ZM2.WALL
ZM15.SIDE
YR40.242
YR40.245

Wall mount bracket
Side mount bracket
Redundancy module
Redundancy module

For details and the complete approval list, see chapter 19.

UL 508

UL 60950-1

ATEX

IECEx

MarineMarineAug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

INDEX
Page
1. Intended Use............................................................. 3
2. Installation Instructions ............................................. 3
3. AC-Input.................................................................... 5
4. DC-Input ................................................................... 6
5. Input Inrush Current .................................................. 6
6. Output ...................................................................... 7
7. Hold-up Time ............................................................ 9
8. DC-OK Relay Contact ................................................. 9
9. Efficiency and Power Losses..................................... 10
10. Lifetime Expectancy and MTBF ................................ 11
11. Functional Diagram ................................................. 11
12. Terminals and Wiring............................................... 12
13. Front Side and User Elements .................................. 13
14. EMC ........................................................................ 14
15. Environment ........................................................... 15
16. Protection Features ................................................. 16
17. Safety Features ....................................................... 16
18. Dielectric Strength ................................................... 17
19. Approved, Fulfilled or Tested Standards ................... 18
20. Regulatory Product Compliance ............................... 20
21. Physical Dimensions and Weight .............................. 21Page
22. Accessories ............................................................. 2222.1. ZM2.WALL-Wall Mounting Bracket ................. 2222.2. ZM15.SIDE-Side Mounting Bracket ................. 2222.3. -YR40.242 - Redundancy Modules .................. 23
22.4. YR40.245 - Redundancy Modules ................... 23
23. Application Notes.................................................... 24
23.1. Repetitive Pulse Loading ................................ 24
23.2. Peak Current Capability.................................. 25
23.3. Back-feeding Loads ........................................ 25
23.4. External Input Protection ............................... 25
23.5. Charging of Batteries ..................................... 26
23.6. Output Circuit Breakers.................................. 26
23.7. Parallel Use to Increase Output Power ........... 27
23.8. Parallel Use for Redundancy........................... 27
23.9. Series Operation ............................................ 28
23.10. Inductive and Capacitive Loads....................... 28
23.11. Operation on Two Phases .............................. 28
23.12. Use in a Tightly Sealed Enclosure.................... 28
23.13. Mounting Orientations................................... 29

The information presented in this document is believed to be accurate and reliable and may change without notice.
No part of this document may be reproduced or utilized in any form without permission in writing from the publisher.

TERMINOLOGY AND ABREVIATIONSPE andsymbolPE is the abbreviation for Protective Earth and has the same meaning as the symbol.

Earth, Ground

This document uses the term “earth” which is the same as the U.S. term “ground”.

t.b.d.

To be defined, value or description will follow later.

AC 230V

A figure displayed with the AC or DC before the value represents a nominal voltage with standard tolerances(usually ±15%) included.
E.g.: DC 12V describes a 12V battery disregarding whether it is full (13.7V) or flat (10V)

230VacA figure with the unit (Vac) at the end is a momentary figure without any additional tolerances included.

50Hz vs. 60Hz

As long as not otherwise stated, AC 230V parameters are valid at 50Hz mains frequency.

may

A key word indicate flexibility of choice with no implied preference.

shall

A key word indicate a mandatory requirement.

shouldA key word indicate flexibility of choice with a strongly preferred implementation.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

1. INTENDED USEThis device is designed for installation in an enclosure and is intended for commercial use, such as in industrial control, process control,
monitoring and measurement equipment or the like.
Do not use this device in equipment, where malfunctioning may cause severe personal injury or threaten human life without additional
appropriate safety devices, that are suited for the end-application.
If this device is used in a manner outside of its specification, the protection provided by the device may be impaired.

2. INSTALLATION INSTRUCTIONSWARNING

Risk of electrical shock, fire, personal injury or death.

- Turn power off before working on the device and protect against inadvertent re-powering.
- Do not open, modify or repair the device.
- Use caution to prevent any foreign objects from entering into the housing.
- Do not use in wet locations or in areas where moisture or condensation can be expected.
- Do not touch during power-on, and immediately after power-off. Hot surface may cause burns.
Obey the following installation instructions:This device may only be installed and put into operation by qualified personnel.
This device does not contain serviceable parts. The tripping of an internal fuse is caused by an internal defect.
If damage or malfunction should occur during installation or operation, immediately turn power off and send unit to the factory for
inspection.
Install device in an enclosure providing protection against electrical, mechanical and fire hazards.
Install the device onto a DIN rail according to EN 60715 with the input terminals on the bottom of the device. Other mounting
orientations require a reduction in output current.
Make sure that the wiring is correct by following all local and national codes. Use appropriate copper cables that are designed for aminimum operating temperature of 60°C for ambient temperatures up to +45°C, 75°C for ambient temperatures up to +60°C and 90°C
for ambient temperatures up to +70°C.
Ensure that all strands of a stranded wire enter the terminal connection. Use ferrules for wires on the input terminals.
The device is designed for pollution degree 2 areas in controlled environments. No condensation or frost is allowed.
The enclosure of the device provides a degree of protection of IP20. The housing does not provide protection against spilled liquids.
The device is designed for overvoltage category II zones. Below 2000m altitude the device is tested for impulse withstand voltages up to
4kV, which corresponds to OVC III according to IEC 60664-1.
The device is designed as “Class of Protection I” equipment according to IEC 61140. Do not use without a proper PE (Protective Earth)connection.
The device is suitable to be supplied from TN, TT or IT mains networks. The continuous voltage between the input terminal and the PE
potential must not exceed 276Vac.
The input can also be powered from batteries or similar DC sources. The continuous voltage between the supply voltage and thePE/ground potential must not exceed 375Vdc.
A disconnecting means shall be provided for the input of the device.
The device is designed for convection cooling and does not require an external fan. Do not obstruct airflow and do not cover ventilation
grid!
The device is designed for altitudes up to 5000m. Above 2000m a reduction in output current is required.
Keep the following minimum installation clearances: 40mm on top, 20mm on the bottom, 5mm left and right side. Increase the 5mm to15mm in case the adjacent device is a heat source. When the device is permanently loaded with less than 50%, the 5mm can be reduced
to zero.
Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

The device is designed, tested and approved for branch circuits up to 20A without additional protection device. If an external fuse isutilized, do not use circuit breakers smaller than 10A B- or C-Characteristic to avoid a nuisance tripping of the circuit breaker.
The maximum surrounding air temperature is +70°C. The operational temperature is the same as the ambient or surrounding air
temperature and is defined 2cm below the device.
The device is designed to operate in areas between 5% and 95% relative humidity.
Only QS20.241 and QS20.241-C1
Installation Instructions for Hazardous Location Areas
The device is suitable for use in Class I Division 2 Groups A, B, C, D locations.
Substitution of components may impair suitability for this environment.
Do not disconnect the device or operate the voltage adjustment unless power has been switched off or the area is known to be nonhazardous.
Only QS20.241-A1
Installation Instructions for Hazardous Location Areas
The device is suitable for use in Class I Division 2 Groups A, B, C, D locations and for use in Group II Category 3 (Zone 2) environments.
Classification: ATEX: EPS 09 ATEX 1 236 X, II 3G Ex ec nC IIC T3 Gc / IECEx EPS 12.0031X
Do not use in mounting orientations other than the input terminals on bottom of the unit. Do not use with DC input voltages or above+60°C ambient.
WARNING EXPLOSION HAZARDS!
Substitution of components may impair suitability for this environment.
Do not disconnect the device or operate the voltage adjustment unless power has been switched off or the area is known to be nonhazardous.
A suitable enclosure must be provided for the end product which has a minimum protection of IP54 and fulfils the requirements of the
EN 60079-0.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

4/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

3. AC-INPUT
AC input
AC input range

nom.

Allowed voltage L or N to earth
Input frequency
Turn-on voltage
Shut-down voltage

max.
nom.
typ.
typ.
typ.

AC 100-240V
85-276Vac
60-85Vac
276-300Vac
276Vac50–60Hz
77Vac
73Vac
53Vac

Input current
Power factor *)Crest factor **)Start-up delay
Rise time

typ.
typ.
typ.
typ.
typ.
typ.
max.

AC 100V
5.47A
0.96
1.6
640ms
80ms
85ms
100mV

Turn-on overshootsuitable for TN-, TT- and IT mains networks
full power for 200ms, no damage between 0 and 85Vac< 500ms
continuous, IEC 62103±6%
steady-state value, see Fig. 3-1
steady-state value, see Fig. 3-1
dynamic value
AC 120V
4.56A
0.95
1.7
610ms
80ms
85ms
100mV

AC 230V
2.48A
0.90
2.05
660ms
80ms
85ms
100mV

at 24V, 20A, see Fig. 3-3
at 24V, 20A, see Fig. 3-4
at 24V, 20A
see Fig. 3-2
0mF, 24V, 20A, see Fig. 3-2
20mF, 24V, 20A, see Fig. 3-2
see Fig. 3-2*)
The power factor is the ratio of the true (or real) power to the apparent power in an AC circuit.
**) The crest factor is the mathematical ratio of the peak value to RMS value of the input current waveform.

Fig. 3-1 Input voltage range

Fig. 3-2 Turn-on behaviour, definitions

Turn-onShut -dow n

full
power
for
200ms

max.
500ms

Input
Voltage

VIN
60V

85V

Start-up
delay

Fig. 3-3 Input current vs. output load at 24V

5
4
3
2

Rise
Time

276V 300Vac

Input Current, typ.

6A

- 5%

OutputVoltage

Overshoot

Rated
input range

POUT

Fig. 3-4 Power factor vs. output load
Power Factor, typ.

1.0

ac
0V
10
Vac
120

0.95

ac
230V

0.85

100Vac120Vac
230Vac

0.9

0.8

1

Output Current

Output Current

0
2

4

6

0.75

8 10 12 14 16 18 20A

2

4

6

8 10 12 14 16 18 20A

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

5/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

4. DC-INPUT
DC input
DC input range
DC input current
Allowed Voltage L/N to Earth
Turn-on voltage
Shut-down voltagenom.

DC 110-150V
88-187Vdc
4.6A
375Vdc
74Vdc
69Vdc

typ.
max.
typ.
typ.

Power Supply
AC

+

L
N
PE

-

110Vdc, at 24V, 20A
IEC 62103
steady state value
steady state value

Instructions for DC use:a) Use a battery or similar DC source.
For other sources contact PULSb) Connect +pole to L and –pole to N.
c) Connect the PE terminal to an earth wire or to the machine
ground.

Fig. 4-1 Wiring for DC Input

Battery-20%/+25%

+
Load

DC

5. INPUT INRUSH CURRENT
An active inrush limitation circuit limits the input inrush current after turn-on of the input voltage and after short input voltage
interruptions.
The charging current into EMI suppression capacitors is disregarded in the first microseconds after switch-on.

max.

AC 100V
13Apeak

AC 120V
13ApeakAC 230V
13Apeak

typ.

11Apeak

9Apeak

7ApeakInrush energy

max.

5A2s

5A2s

5A2s

Inrush delay (A)

typ.

400ms

400ms

650ms

Inrush current

over entire temperature range;
mains interruptions > 750ms
over entire temperature range;
mains interruptions > 750ms
over entire temperature range;
mains interruptions > 750ms
see (A) in Fig. 5-1

Fig. 5-1 Input inrush current, typical behaviour

A
Input
Current

Input Voltage
OutputVoltage

A….

Inrush delay

Input:
Output:Ambient:
Upper curve:
Middle curve:
Lower curve:Time basis:

230Vac
24V, 20A
25°C
Input current 5A / DIVInput voltage 500V / DIV
Output voltage 20V / DIV
100ms / DIV

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

6/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

6. OUTPUT
Output voltage
Adjustment range
Factory settingLine regulation
Load regulation
Ripple and noise voltage
Output current

Output power

nom.
max.
typ.
max.
max.
max.
nom.
nom.
nom.

24V
24-28V
30V ****)
24.1V
10mV
100mV
100mVpp
20A
17A
30A *)

nom.

26A *)

nom.
nom.
typ.
min.
max.
typ.

Short-circuit current

min.
max.
max.

480W
720W *)
4s
3.5s
4.5s
7s
cont. current
HiccupPLUS mode**)30A ***)
40A ***)
14A ***)

Output capacitancetyp.

8 500µF

BonusPower time

BonusPower recovery time
Overload behaviour

*)

**)

***)
****)

guaranteed
at clockwise end position of potentiometer±0.2%, at full load, cold unit
60-300Vac
static value, 0A → 20A
20Hz to 20MHz, 50Ohm
continuously available at 24V, see Fig. 6-1
continuously available at 28V, see Fig. 6-1
short term available BonusPower *),at 24V, for typical 4s, see Fig. 6-1
short term available BonusPower *),at 28V, for typical 4s, see Fig. 6-1
continuously available
short term available BonusPower *)duration until the output voltage dips, see Fig. 6-2

overload free time to reset power manager Fig. 6-4
output voltage > 20Vdc, see Fig. 6-1
output voltage < 20Vdc, see Fig. 6-1
load impedance 50mOhm, see Fig. 6-3
load impedance 50mOhm, see Fig. 6-3
average (R.M.S.) current, load impedance <10mOhm, see Fig.
6-3
included inside the power supply

BonusPower, short term power capability (up to typ. 4s)
The power supply is designed to support loads with a higher short-term power requirement without damage or shutdown. The short-term duration is
hardware controlled by an output power manager. This BonusPower is repeatedly available. Detailed information can be found in chapter 23.1. If thepower supply is loaded longer with the BonusPower than shown in the Bonus-time diagram (see Fig. 6-2), the max. output power is automatically reduced
to 480W. If the power requirement is continuously above 480W and the voltage falls below approx. 20V (due to the current regulating mode at overload),
the unit shuts-off and makes periodical restart attempts. This behaviour is called hiccup mode, which is described below. If the voltage is above 20V, theunit continuously delivers current.
HiccupPLUS ModeAt heavy overloads (when output voltage falls below 20V), the power supply delivers continuous output current for 2s. After this, the output is switched
off for approx. 17s before a new start attempt is automatically performed. This cycle is repeated as long as the overload exists. If the overload has beencleared, the device will operate normally. See also Fig. 6-3.
During the off-period a small rest voltage and rest current is present on the output.
Discharge current of output capacitors is not included.
This is the maximum output voltage which can occur at the clockwise end position of the potentiometer due to tolerances. It is not guaranteed value
which can be achieved. The typical value is about 28.5V.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

7/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

Peak current capability (up to several milliseconds)
The power supply can deliver a peak current which is higher than the specified short term current. This helps to start current demanding
loads or to safely operate subsequent circuit breakers.
The extra current is supplied by the output capacitors inside the power supply. During this event, the capacitors will be discharged andcauses a voltage dip on the output. Detailed curves can be found in chapter 23.2.
Peak current voltage dips

typ.
typ.
typ.

from 24V to 20V
from 24V to 17Vfrom 24V to 16V

at 40A for 50ms, resistive load
at 100A for 2ms, resistive load
at 100A for 5ms, resistive load

Fig. 6-1 Output voltage vs. output current, typ.

Fig. 6-2 Bonus time vs. output power

Output Voltage

10 15 20 25 30 35 40A

10s
9
8
7
6
m ax
5
4
3
typ
m in
2
1
Output Power
0528W 576W 624W 672W 720W 768W

Fig. 6-3 Short-circuit on output, hiccup mode (typ.)Fig. 6-4 BonusPower recovery time

28V
24

B

20
C

16

A

12
A Short term <5s then auto
switching to curve B + C
B Continuously available

840

OutputCurrent

C Below 20Vdc hiccup mode

05

OutputCurrent

End ofshort circuit

Start ofshort circuit

Limitation by
Power Manager

Power
Demand

35A

100%
t

t

0
2s

17s

2s

17s

2s

Recovery Time
Bonus Power disabled

Bonus
Time

OutputVoltage

17st

The BonusPower is available as soon as power comes on and immediately after the end of an output short circuit or output overload.
Fig. 6-5 BonusPower after input turn-on

Fig. 6-6 BonusPower after output short

Short ofOutput

Input
Voltage

OutputVoltage
OutputVoltage150%
Output
Power

100%

Bonus
Power

Output
Power

150%

Bonus
Power

100%

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

8/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

7. HOLD-UP TIME
Hold-up TimeAC 100V
64ms
32ms

typ.
typ.

Fig. 7-1 Hold-up time vs. input voltage

100ms Hold-up
Time

AC 230V
99ms
51ms

t yp .
20A ,24V,
A , m in .
24V, 20

Zero Transition
Input
Voltage

120

155

- 5%

OutputVoltage
Hold-up Time

Input Voltage85

at 24V, 10A, see Fig. 7-1
at 24V, 20A, see Fig. 7-1

Fig. 7-2 Shut-down behaviour, definitions

p.
, ty
10A
,
24V
in.
A, m
, 10
V
4
2

90
80
70
60
50
40
30
20
10

AC 120V
64ms
32ms

190

230Vac8. DC-OK RELAY CONTACT
This feature monitors the output voltage, which is produced by the power supply itself. It is independent of a back-fed voltage from aunit connected in parallel to the power supply output.
Contact closes
Contact opens

As soon as the output voltage reaches the adjusted output voltage level.
As soon as the output voltage dips more than 10% below the adjusted output voltage.
Short dips will be extended to a signal length of 250ms. Dips shorter than 1ms will be ignored.
As soon as the output voltage exceeds 90% of the adjusted voltage.
max.
60Vdc 0.3A, 30Vdc 1A, 30Vac 0.5A
resistive loadmin.
1mA at 5Vdc
min. permissible load
See dielectric strength table in chapter 18.

Contact re-closes
Contact ratings
Isolation voltage

Fig. 8-1 DC-OK relay contact behavior

VOUT = VADJ
10%

<
1ms

open

Note:

closed>1ms

0.9* VADJ

250ms

open

closedThe DC-OK feature requires that the output voltage reaches the nominal (=adjusted) level after turn-on in order to function according to specification. If
this level cannot be achieved, the overload LED will be on and the DC-OK contact will be open. The overload signal will only shut off as soon as the adjusted
voltage is reached. This is an important condition to consider particularly, if the load is a battery, the power supply is used in parallel or the power supply isused for N+1 redundant system.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

9/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

9. EFFICIENCY AND POWER LOSSES
Efficiency
Average efficiency *)

typ.
typ.

AC 100V
91.6%
91.0%

Power losses

typ.
typ.

9.0W
44.0W

*)

AC 120V
92.4%
91.8%

AC 230V
93.9%
92.9%

9.2W
39.6W

10.0W
31.4W

at 24V, 20A
25% at 5A, 25% at 10A, 25% at 15A.
25% at 20A
at 24V, 0A
at 24V, 20A

The average efficiency is an assumption for a typical application where the power supply is loaded with 25% of the nominal load for 25% of the time, 50% of
the nominal load for another 25% of the time, 75% of the nominal load for another 25% of the time and with 100% of the nominal load for the rest of thetime.

Fig. 9-1

Efficiency vs. output current at 24V, typ

230Vac

94%
93
92
91
90
89
88
87
86

120Vac100VacOutput Current

Fig. 9-3

Losses vs. output current at 24V, typ.

Power Losses

Efficiency

4Fig. 9-2

6

8

45W
40
35
30
25
20
15
10
5

Output Current

0

10 12 14 16 18 20A

Efficiency vs. input voltage at 24V, 20A, typ.

100Vac120Vac
230VacFig. 9-4

2

4

6

8 10 12 14 16 18 20A

Losses vs. input voltage at 24V, 20A, typ.

Efficiency

Power Losses

94%

50W

93

45

92

40

91

35

90

30
25

89
Input Voltage

88
85

120

155

190

Input Voltage

20
225 260Vac

85

120

155

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany190

225 260Vac

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24V, 20A, SINGLE PHASE INPUT

Q-Series

10. LIFETIME EXPECTANCY AND MTBF
Lifetime expectancy *)MTBF **) SN 29500, IEC 61709
MTBF **) MIL HDBK 217F

AC 100V
54 000h
135 000h
153 000h *)407 000h
749 000h
204 000h

AC 120V
59 000h
143 000h
165 000h *)441 000h
799 000h
215 000h

AC 230V
71 000h
164 000h
200 000h *)469 000h
840 000h
229 000h

273 000h

288 000h

308 000h

at 24V, 20A and 40°C
at 24V, 10A and 40°C
at 24V, 20A and 25°C
at 24V, 20A and 40°C
at 24V, 20A and 25°C
at 24V, 20A and 40°C;
Ground Benign GB40
at 24V, 20A and 25°C;
Ground Benign GB25*)

The Lifetime expectancy shown in the table indicates the minimum operating hours (service life) and is determined by the lifetime expectancy of the built-in
electrolytic capacitors. Lifetime expectancy is specified in operational hours and is calculated according to the capacitor’s manufacturer specification. The
manufacturer of the electrolytic capacitors only guarantees a maximum life of up to 15 years (131 400h). Any number exceeding this value is a calculated
theoretical lifetime which can be used to compare devices.
**) MTBF stands for Mean Time Between Failure, which is calculated according to statistical device failures, and indicates reliability of a device. It is the statisticalrepresentation of the likelihood of a unit to fail and does not necessarily represent the life of a product.
The MTBF figure is a statistical representation of the likelihood of a device to fail. A MTBF figure of e.g. 1 000 000h means that statistically one unit will failevery 100 hours if 10 000 units are installed in the field. However, it can not be determined if the failed unit has been running for 50 000h or only for 100h.

11. FUNCTIONAL DIAGRAM
Fig. 11-1 Functional diagram
OutputVoltage
Regulator

L
N

Input Fuse
Input Filter
Input Rectifier
Active Inrush Limiter

PFC
ConverterPower
Converter

OutputFilterVOUT++
OverloadLED

Temperature
Shutdown

OutputPower
Manager

OutputOverVoltage
Protection

OutputVoltage
Monitor

DC-ok
LED
DC-ok
Relay

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

DC-okContact

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24V, 20A, SINGLE PHASE INPUT

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12. TERMINALS AND WIRING
Bi-stable, quick-connect spring clamp terminals. Shipped in open position.
- IP20 Finger safe construction.
- Suitable for field- and factory installation.
Input
spring-clamp terminal
0.5-6mm2
0.5-4mm220-10 AWG
10mm
2.8mm

Type
Solid wire
Stranded wire
American Wire Gauge
Wire stripping lengthMax. wire diameter(including ferrules)

Outputspring-clamp terminal
0.5-6mm2
0.5-4mm220-10 AWG
10mm
2.8mm

Instructions:a) Use appropriate copper cables that are designed for minimum
operating temperatures of:
60°C for ambient up to 45°C and
75°C for ambient up to 60°C minimum
90°C for ambient up to 70°C minimum.
b) Follow national installation codes and installation regulations!
c) Ensure that all strands of a stranded wire enter the terminal
connection!
d) Do not use the unit without PE connection.
e) Unused terminal compartments should be securely tightened.
f) Ferrules are allowed.

DC-OK signal
spring-clamp terminal
0.3-4mm2
0.3-2.5mm2
26-12 AWG
6mm
2.25mmFig. 12-1

Connecting a wire

1. Insert the wire

2. Close the lever

To disconnect wire:
reverse the procedure

Daisy Chaining of Outputs:
Daisy chaining (jumping from one power supply output to the next) is allowed as long as the average output current through one
terminal pin does not exceed 25A. If the current is higher, use a separate distribution terminal block as shown in Fig. 12-3.
Fig. 12-2 Daisy chaining of outputs

Fig. 12-3 Using distribution terminals

max 25A!

OutputOutput

+ + -

+ + -

-

-

+

-

Load

OutputOutput

+ + -

+ + -

-

-

Power
SupplyPower
SupplyPower
SupplyPower
Supply

Input

Input

Input

Input

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

+

-

Load

Distribution
Terminals

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24V, 20A, SINGLE PHASE INPUT

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13. FRONT SIDE AND USER ELEMENTS
Fig. 13-1 Front sideA

Input Terminals (Quick-connect spring-clamp terminals)
N, LLine input
PE (Protective Earth) input

B

Output Terminals (Quick-connect spring-clamp terminals, two pins per pole)+
Positive output–
Negative (return) output

C

DC-OK Relay Contact (Quick-connect spring-clamp terminals)
The DC-OK relay contact is synchronized with the DC-OK LED.
See chapter 8 for details.

D

Output voltage potentiometer
Open the flap to adjust the output voltage. Factory set: 24.1V

E

DC-OK LED (green)
On, when the output voltage is >90% of the adjusted output voltage

F

Overload LED (red)On, when the voltage on the output terminals is <90% of the adjusted output
voltage, or in case of a short circuit in the output. Input voltage is required.

Indicators, LEDs
Normal mode
During BonusPower
Overload (VOUT < 90%)
Output short circuit
Temperature Shut-down
No input power

Overload LED
OFF
OFF
*)
*)
*)
OFF

DC-OK LED
ON
ON
OFF
OFF
OFF
OFF

DC-OK Contact
ClosedClosed
Open
Open
Open
Open

*) Up to 4s of overloading, the power supply delivers continuous output current. After this, the output power is reduced to nearly zero for approx. 17s before a
new start attempt is automatically performed. If the overload has been cleared, the device will operate normally. If the overload still exists, the output current
will be delivered for 2 to 4s (depending on the overload) again followed by a 17s rest time. This cycle is repeated as long as the overload exists.
The red overload LED is permanently on when the overload current is continuously flowing. During the 17s rest period, the red LED is flashing with a frequency
of approx. 1.3Hz.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

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14. EMCThe power supply is suitable for applications in industrial environment as well as in residential, commercial and light industry
environment without any restrictions. A detailed EMC report is available on request.
EMC Immunity
Electrostatic discharge
Electromagnetic RF field
Fast transients (Burst)

Surge voltage on input
Surge voltage on output
Surge voltage on DC-OK
Conducted disturbance
Mains voltage dips

Voltage interruptions
Voltage sags

Powerful transients

According generic standards: EN 61000-6-1 and EN 61000-6-2
contact discharge
8kV
EN 61000-4-2
air discharge
15kV
EN 61000-4-3
80MHz-2.7GHz
10V/m
EN 61000-4-4
input lines
4kV
output lines
2kV
DC-OK signal (coupling clamp)
1kV
EN 61000-4-5
L→N
2kV
L → PE, N → PE
4kV
EN 61000-4-5+→1kV+ / - → PE
1kV
EN 61000-4-5
DC-OK signal → PE
1kV
EN 61000-4-6
0.15-80MHz
10V
EN 61000-4-11
0% of 100Vac
0Vac, 20ms
40% of 100Vac
40Vac, 200ms
70% of 100Vac
70Vac, 500ms
0% of 200Vac
0Vac, 20ms
40% of 200Vac
80Vac, 200ms
70% of 200Vac
140Vac, 500ms
EN 61000-4-11
0% of 200Vac (=0V)
5000msSEMI F47
dips on the input voltage according to SEMI F47 standard
80% of 120Vac (96Vac)
1000ms70% of 120Vac (84Vac)
500ms
50% of 120Vac (60Vac)
200ms
VDE 0160
over entire load range
750V, 1.3ms

Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion C
Criterion A
Criterion A
Criterion A
Criterion A
Criterion C
Criterion A
Criterion A
Criterion A
Criterion C

Criterions:
A: Power supply shows normal operation behavior within the defined limits.
C: Temporary loss of function is possible. Power supply may shut-down and restarts by itself. No damage or hazards for the power supply will occur.

EMC Emission
According generic standards: EN 61000-6-3 and EN 61000-6-4
Conducted emission
EN 55011, EN 55032, FCC Part 15, CISPR 11, CISPR 32
Class B
input lines
Conducted emission
IEC/CISPR 16-1-2, IEC/CISPR 16-2-1
limits for DC power port acc. EN
output lines **)61000-6-3 not fulfilled ***)
Radiated emission
EN 55011, EN 55032
Class B
Harmonic input current
EN 61000-3-2
fulfilled for class A equipment
Voltage fluctuations, flicker
EN 61000-3-3
fulfilled *)This device complies with FCC Part 15 rules.
Operation is subjected to following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.
*) tested with constant current loads, non pulsing**) for information only, not mandatory for EN 61000-6-3***) Quasi-peak values fulfilled, average values +5dB

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

Q-Series

Switching Frequencies

The power supply has four converters with four different switching frequencies included. One isnearly constant. The others are input voltage and load dependent.
100kHzResonant converter, nearly constant
110kHz to 500kHz
Boost converter, input voltage and load dependent
73kHz to 114kHz
PFC converter, input voltage and load dependent
35kHz to 45kHz
Aux. converter, input voltage and load dependent

Switching frequency 1
Switching frequency 2
Switching frequency 3
Switching frequency 4

15. ENVIRONMENT
Operational temperature *)Storage temperature
Output derating
Humidity **)Vibration sinusoidal-25°C to +70°C-40 to +85°C
12W/°C
5 to 95% r.H.
2-17.8Hz: ±1.6mm; 17.8-500Hz: 2g
2 hours / axis
15g 6ms, 10g 11ms
3 bumps / direction, 18 bumps in total
30g 6ms, 20g 11ms
3 bumps / direction, 18 bumps in total
0 to 2000m
2000 to 6000m

Shock

Altitude

Altitude derating
Over-voltage category

reduce output power according Fig. 15-1
for storage and transportation
60-70°C
IEC 60068-2-30
IEC 60068-2-6
IEC 60068-2-27, DIN rail mounting
IEC 60068-2-27, with wall mounting bracket
ZM2.WALL
without any restrictions
reduce output power or ambient temperature,
see Fig. 15-2
IEC 62103, EN 50178, overvoltage category II> 2000m, see Fig. 15-2
IEC 62103, EN 50178, altitudes up to 2000m
altitudes from 2000m to 6000m
IEC 62103, EN 50178, not conductive

30W/1000m or 5°C/1000m
III
II
2

Degree of pollution*)
Operational temperature is the same as the ambient temperature and is defined as the air temperature 2cm below the unit.
**) Do not energize while condensation is present

Fig. 15-1 Output current vs. ambient temp.

Allowed Output
Current at 24V

Fig. 15-2 Output current vs. altitude

Allowed Output
Current at 24V

30A

30A

f or t yp. 4s

25
20

20

continuous

15

15

10

10

5

5

0
-25

f or t yp. 4s

25

Ambient Temperature

0

20

40

continuous

A

A... Tamb < 60°C
B... Tamb < 50°C
C... Tamb < 40°C

0

2000

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

C

Altitude0
60 70°C

B

4000

6000m

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24V, 20A, SINGLE PHASE INPUT

Q-Series

16. PROTECTION FEATURES
Output protection
Output over-voltage protection

Degree of protection
Penetration protection
Over-temperature protection
Input transient protection
Internal input fuse*)

Electronically protected against overload, no-load and short-circuits *)typ. 32Vdc
In case of an internal power supply defect, a redundant circuit
max. 37Vdc
limits the maximum output voltage. The output shuts down andautomatically attempts to restart.
IP 20
EN/IEC 60529> 3.5mm / > 5mm
top side / bottom side, e.g. screws, small partsyes
Output shut-down with automatic restart
MOV (Metal Oxide Varistor)
included
not user replaceable

In case of a protection event, audible noise may occur.

17. SAFETY FEATURES
Input / output separation *)Class of protection
Isolation resistancePE resistance
Touch current (leakage current)

*)

SELV
IEC/EN 60950-1
PELV
IEC/EN 60204-1, EN 50178, IEC 62103, IEC 60364-4-41
double or reinforced insulation
I
PE (Protective Earth) connection required> 5MOhm
input to output, 500Vdc< 0.1Ohm
typ. 0.23mA / 0.63mA
100Vac, 50Hz, TN-,TT-mains / IT-mains
typ. 0.34mA / 0.93mA
120Vac, 60Hz, TN-,TT-mains / IT-mains
typ. 0.58mA / 1.56mA
230Vac, 50Hz, TN-,TT-mains / IT-mains< 0.31mA / 0.77mA
110Vac, 50Hz, TN-,TT-mains / IT-mains< 0.45mA / 1.13mA
132Vac, 60Hz, TN-,TT-mains / IT-mains< 0.80mA / 2.00mA
264Vac, 50Hz, TN-,TT-mains / IT-mains

double or reinforced insulation

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

Q-Series

18. DIELECTRIC STRENGTH
The output voltage is floating and has no ohmic connection to the ground. Type and factory tests are conducted by the manufacturer.
Field tests may be conducted in the field using the appropriate test equipment which applies the voltage with a slow ramp (2s up and 2sdown). Connect all input-terminals together as well as all output poles before conducting the test. When testing, set the cut-off current
settings to the value in the table below.
Type test

60s

A
2500Vac

B
3000Vac

C
500VacD
500VacFactory test

5s

2500Vac

2500Vac

500Vac

500VacField test

5s

2000Vac

2000Vac

500Vac

500VacCut-off current setting> 15mA> 15mA> 40mA> 1mA

Fig. 18-1 Dielectric strength

Input

DC-ok
B* )

L
N

B

A

D
OutputEarth, PEC+-

To fulfil the PELV requirements according to EN60204-1 § 6.4.1, werecommend that either the + pole, the – pole or any other part of the output
circuit shall be connected to the protective earth system. This helps to avoid
situations in which a load starts unexpectedly or can not be switched off
when unnoticed earth faults occur.

B*) When testing input to DC-OK ensure that the max. voltage between DC-OK and the output is not exceeded (column D). We recommend connecting DC-OK
pins and the output pins together when performing the test.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

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19. APPROVED, FULFILLED OR TESTED STANDARDSUL 508

IEC 61010-2-201

IEC 60950-1
IEC 62368-1

UL 60950-1

ATEX(only QS20.241-A1)

IECEx(only QS20.241-A1)

Class I Div 2

Marine (DNV)(only QS20.241, QS20.241-C1)

UL Certificate
Listed equipment for category NMTR - Industrial Control Equipment
Applicable for US and Canada
E-File: E198865
Manufacturer's Declaration
Electrical Equipment for Measurement, Control and Laboratory Use - Particularrequirements for control equipment
CB Scheme Certificate
General safety requirements for Information Technology Equipment (ITE)
CB Scheme Certificate
IEC 62368-1 Audio/video, information and communication technology
equipment - Safety requirements
Output safety level: ES1
UL Certificate
Recognized component for category QQGQ - Information Technology
Equipment (ITE)
Applicable for US and Canada
E-File: E137006
Agency Certificate (Bureau Veritas)
EN 60079-0 Explosive atmospheres - General requirements
EN 60079-7, EN 60079-15 Equipment protection by type of protection "e" and"n"Certificate: EPS 09 ATEX 1 236 X
Temperature Code: T3
Type of Protection: ec nC
IECEx Certificate
IEC 60079-0 Explosive atmospheres - General requirements
IEC 60079-7, IEC 60079-15 Equipment protection by type of protection "e" and"n"Certificate: IECEx EPS 12.0031X
Temperature Code: T3
Type of Protection: ec nC
CSA Certificate
Power Supplies for Hazardous Location
Applicable for Canada and US
CSA Class: 5318-01 (Canada), 5318-81 (USA)
Temperature Code: T3
Groups: A, B, C and D
DNV Certificate
DNV Type approved product
Certificate: TAA00001ST
Temperature: Class D
Humidity: Class B
Vibration: Class C
EMC: Class A
Enclosure: Class A

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

18/29

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24V, 20A, SINGLE PHASE INPUT

Q-Series

Marine (DNV)(only QS20.241-A1)

Marine (ABS)(only QS20.241, QS20.241-C1)
IEC 61558-2-16(only QS20.241)

SEMI F47

IEC 60068-2-60(only QS20.241, QS20.241-A1)

ISA-71.04-1985(only QS20.241, QS20.241-A1)

VDMA 24364

DNV Certificate
DNV Type approved product
Certificate: TAA00002YX
Temperature: Class D
Humidity: Class B
Vibration: Class C
EMC: Class A
Enclosure: Class A
ABS Design Assessment Certificate
ABS (American Bureau of Shipment) assessed product
Certificate: 22-2231447-PDA
Test Certificate
Safety of transformers, reactors, power supply units and similar products for
supply voltages up to 1100 V
Particular requirements and tests for switch mode power supply units andtransformers for switch mode power supply units
Test Report
Voltage Sag Immunity for Semiconductor Processing Equipment
Tested for AC 120V and 208V L-L or L-N mains voltages, nominal output voltage
and nominal output load
Manufacturer's Declaration (Online Document)
Environmental Tests, Flowing Mixed Gas Corrosion Test
Test Ke - Method 4
H2S: 10ppb
NO2: 200ppb
Cl2: 10ppb
SO2: 200ppb
Test Duration: 3 weeks, which simulates a service life of 10 years.
Manufacturer's Declaration (Online Document)
Airborne Contaminants Corrosion Test
Severity Level: G3 Harsh
H2S: 100ppb
NOx: 1250ppb
Cl2: 20ppb
SO2: 300ppb
Test Duration: 3 weeks, which simulates a service life of 10 years.
Paint Wetting Impairment Substances Test (or LABS-Test)
Tested for Zone 2 and test class C1 according to VDMA 24364-C1-L/W for
solvents and water-based paints

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

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20. REGULATORY PRODUCT COMPLIANCE
EU Declaration of Conformity

REACH Regulation (EU)

WEEE Regulation

UKCA

CCC
(only QS20.241-A1)

KC

The CE mark indicates conformance with the- EMC directive- Low-voltage directive (LVD) (only QS20.241, QS20.241-C1)- RoHS directive- ATEX directive (only QS20.241-A1)
Manufacturer's Declaration
EU regulation regarding the Registration, Evaluation, Authorisation andRestriction of Chemicals (REACH) fulfilled.
EU Regulation (EC) 1907/2006.
Manufacturer's Declaration
EU Regulation on Waste Electrical and Electronic Equipment
Registered as business to business (B2B) products.
EU Regulation 2012/19/EU
UKCA Declaration of Conformity
Trade conformity assessment for England, Scotland and WalesThe UKCA mark indicates conformity with the UK Statutory Instruments
2016 No.1101 (only QS20.241, QS20.241-C1),
2016 No. 1107 (only QS20.241-A1)
2016 No.1091,
2012 No.3032
CCC Certificate
China Compulsory Certification (CNCA-C23-01:2019)
Certificate for devices made in Suzhou/China (PULS Electronics):
2021122303114740
Certificate for devices made in Chomutov/Czech Republic (PULS investiční):2021122303114741
CCC-ExKC Korean Certification
Korean - Registration of Broadcasting and Communication Equipment
Registered under Clause3, Article 58-2 of Radio Waves Act.
Registration No. R-R-PUG-QS20_241.

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

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21. PHYSICAL DIMENSIONS AND WEIGHT
WeightDIN rail

Installation Clearances

1200g
Use 35mm DIN rails according to EN 60715 or EN 50022 with a height of 7.5 or 15mm.
The DIN rail depth must be added to the unit depth (127mm) to calculate the total required installation
depth.
See chapter 2

Fig. 21-1 Front viewFig. 21-2 Side view

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

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22. ACCESSORIES
22.1. ZM2.WALL-WALL MOUNTING BRACKETThis bracket is used to mount the power
supply onto a flat surface without utilizing a DIN rail.

22.2. ZM15.SIDE-SIDE MOUNTING BRACKETThis bracket is used to mount Dimension units sideways with or without utilizing a DIN rail. The two aluminum brackets and the black
plastic slider of the unit have to be detached, so that the steel brackets can be mounted.
For sideway DIN rail mounting, the removed aluminum brackets and the black plastic slider need to be mounted on the steel bracket.

Side mounting with DIN rail brackets

Side mounting without DIN rail brackets

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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24V, 20A, SINGLE PHASE INPUT

Q-Series22.3. -YR40.242 - REDUNDANCY MODULES(2x 20A Inputs, 1x 40A output)
The YR40.242 is equipped with two input channels, which are individually decoupled by utilizing mosfet
technology. Using mosfets instead of diodes reduces the heat generation and the voltage drop between
input and output. The YR40.242 does not require an additional auxiliary voltage and is self-powered even incase of a short circuit across the output.
Due to the low power losses, the unit is very slender and only requires 36mm width on the DIN rail.

22.4. YR40.245 - REDUNDANCY MODULES(1x 40A input, 1x 40A output)
The YR40.245 is a 40A single channel redundancy module, which is equipped with a plug connector on the
output. The plug connector allows replacing the power supply or the redundancy module while the system
is running. The plug connector avoids that the output wires can touch and short the load circuit.
The YR40.245 is very slender and only requires 46mm width on the DIN rail. It also utilizes mosfet
technology instead of diodes for low heat generation and a minimal voltage drop between input andoutput. It does not require an additional auxiliary voltage and is self-powered even in case of a short circuit
across the output.

Fig. 22-1 Typical 1+1 Redundant configuration for 20A witha dual redundancy module
24V
20A
Load

Fig. 22-2 Typical N+1 or 1+1 Redundant configuration for 20A with multiple YR40.245
redundancy modules

FailureMonitorFailureMonitor

24V
20A
Load

-

+
++ - -

DC24V,20A OK

QS20.241
Power
SupplyL N PE+-

OutputYR40.242* )Redundancy
ModuleInput Input
12+ - + -++ - -++ - -

DC24V,20A OK

QS20.241
Power
SupplyQS20.241
Power
SupplyL
N
PE

also possible

OutputDC24V,20A OK

YR40.245
Redundancy
Module+QS20.241
Power
SupplyYR40.245
Redundancy
Module
Input

-

I

I

-

+
++ - -Input

L N PEL N PE* ) YR40.241

I

OutputDC24V,20A OK

L N PE

+

-

I

L
N
PE

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

23/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

23. APPLICATION NOTES
23.1. REPETITIVE PULSE LOADING
Typically, a load current is not constant and varies over time. This power supply is designed to support loads with a higher short-term
power demand (=BonusPower). The short-term duration is hardware controlled by an output power manager and is available on arepeated basis. If the BonusPower load lasts longer than the hardware controller allows it, the output voltage will dip and the next
BonusPower is available after the BonusPower recovery time (see chapter 6) has elapsed.
To avoid this, the following rules must be met:a)
The power demand of the pulse must be below 150% of the nominal output power.
b)
The duration of the pulse power must be shorter than the allowed BonusPower time. (see output chapter)c)
The average (R.M.S.) output current must be below the specified continuous output current.
If the R.M.S. current is higher, the unit will respond with a thermal shut-down after a period of time. Use the maximum duty cycle
curve (Fig. 23-2) to check if the average output current is below the nominal current.
Fig. 23-1 Repetitive pulse loads, definitions

Fig. 23-2 Max. duty cycle curve

1.0

PPEAK TPEAK

DutyCycle

P0 = 10%
P0 = 50%
P0 = 75%

0.8

T0

max.
150%

0.6

100%

0.4

P0

P0 = 100%

0.2

PPEAK

0
100

P0
PPEAK
T0
TPEAK

Example:Base load (W)Pulse load (above 100%)
Duration between pulses (s)Pulse duration (s)110DutyCycle =

T0 =

120

130

140

150%

Tpeak
Tpeak + T0

Tpeak - (DutyCycle x Tpeak)
DutyCycle

A load is powered continuously with 240W (= 50% of the rated output load). From time to time a peak power of 720W (=150% of the rated output load) is needed for 1 second.
The question is: How often can this pulse be supplied without overloading the power supply?
- Make a vertical line at PPEAK = 150% and a horizontal line where the vertical line crosses the P0 = 50% curve. Read themax. duty cycle from the duty cycle-axis (= 0.37)- Calculate the required pause (base load) length T0:- Result: The required pause length = 1.7s

T0=

Tpeak - (DutyCycle x Tpeak)- Max. repetition rate = pulse +pause length = 2.7s

DutyCycle=

1s- (0.37 x 1s)
0.37

=1.7s

More examples for pulse load compatibility:
PPEAK
720W
720W
600W

P0
480W
0W
240W

TPEAK
1s
1s
1s

T0
>25s
>1.3s
> 0.75s

PPEAK
720W
720W
720W

P0
240W
240W
240W

TPEAK
0.1s
1s
3s

T0
>0.16s
>1.6s>4.9s

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

24/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series23.2. PEAK CURRENT CAPABILITY
Solenoids, contactors and pneumatic modules often have a steady state coil and a pick-up coil. The inrush current demand of the pickup coil is several times higher than the steady-state current and usually exceeds the nominal output current (including the PowerBoost).
The same situation applies when starting a capacitive load.
Branch circuits are often protected with circuit breakers or fuses. In case of a short or an overload in the branch circuit, the fuse needs acertain amount of over-current to trip or to blow. The peak current capability ensures the safe operation of subsequent circuit breakers.
Assuming the input voltage is turned on before such an event, the built-in large sized output capacitors inside the power supply candeliver extra current. Discharging this capacitor causes a voltage dip on the output. The following two examples show typical voltage
dips:Fig. 23-3 Peak load with 2x the nominal current for 50ms,
typ.

Fig. 23-4 Peak load with 5x the nominal current for 5ms,
typ.

24V
OutputVoltage

24V
40A

OutputVoltage

100A
16V

20V

OutputCurrent

0A

OutputCurrent

0A
1ms/DIV

10ms/DIVPeak load 40A (resistive) for 50ms
Output voltage dips from 24V to 20V.

Peak load 100A (resistive) for 5ms
Output voltage dips from 24V to 16V.

Please note: The DC-OK relay triggers when the voltage dips more than 10% for longer than 1ms.

23.3. BACK-FEEDING LOADS
Loads such as decelerating motors and inductors can feed voltage back to the power supply. This feature is also called return voltage
immunity or resistance against Back- E.M.F. (Electro Magnetic Force).
This power supply is resistant and does not show malfunctioning when a load feeds back voltage to the power supply. It does not matter
whether the power supply is on or off.
The maximum allowed feed-back-voltage is 34Vdc. The absorbing energy can be calculated according to the built-in large sized output
capacitor which is specified in chapter 6.

23.4. EXTERNAL INPUT PROTECTION
The unit is tested and approved for branch circuits up to 20A. An external protection is only required if the supplying branch has anampacity greater than this. Check also local codes and local requirements. In some countries local regulations might apply.
If an external fuse is necessary or utilized, minimum requirements need to be considered to avoid nuisance tripping of the circuit
breaker. A minimum value of 10A B- or C-Characteristic breaker should be used

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

25/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series23.5. CHARGING OF BATTERIESThe power supply can be used to charge lead-acid or maintenance free batteries. (Two 12V batteries in series)
Instructions for charging batteries:a)

Set output voltage (measured at no load and at the battery end of the cable) very precisely to the end-of-charge voltage.
End-of-charge voltage

27.8V

27.5V

27.15V

26.8V

Battery temperature

10°C

20°C

30°C

40°C

b)

Use a 30A or 32A circuit breaker (or blocking diode) between the power supply and the battery.

c)Ensure that the output current of the power supply is below the allowed charging current of the battery.

d)Use only matched batteries when putting 12V types in series.

e)

The return current to the power supply (battery discharge current) is typ. 9mA when the power supply is switched off (except incase a blocking diode is utilized).

23.6. OUTPUT CIRCUIT BREAKERS
Standard miniature circuit breakers (MCB’s or UL1077 circuit breakers) are commonly used for AC-supply systems and may also be usedon 24V branches.
MCB’s are designed to protect wires and circuits. If the ampere value and the characteristics of the MCB are adapted to the wire sizethat is used, the wiring is considered as thermally safe regardless of whether the MCB opens or not.
To avoid voltage dips and under-voltage situations in adjacent 24V branches which are supplied by the same source, a fast (magnetic)
tripping of the MCB is desired. A quick shutdown within 10ms is necessary corresponding roughly to the ride-through time of PLC's. Thisrequires power supplies with high current reserves and large output capacitors. Furthermore, the impedance of the faulty branch mustbe sufficiently small in order for the current to actually flow. The best current reserve in the power supply does not help if Ohm’s law
does not permit current flow. The following table has typical test results showing which B- and C-Characteristic MCBs magnetically trip
depending on the wire cross chapter and wire length.
Fig. 23-5 Test circuit

Power Supply

AC

MCB

+

+
Wire length

DC S1... Fault simulation switch

*)

Load

S1

-

Maximal wire length*) for a fast (magnetic) tripping:
0.75mm²
1.0mm²1.5mm²
C-2A
26m
35m
62m
C-3A
23m
29m
54m
C-4A
15m
19m
31m
C-6A
7m
10m
15m
C-8A
5m
7m
10m
C-10A
2m
3m
5m
C-13A
1m
B-6A
19m
27m
38m
B-10A
7m
11m
14m
B-13A
1m
2m
3m

2.5mm²
82m
72m
51m
26m
16m
7m
2m
57m
23m
5m

Don’t forget to consider twice the distance to the load (or cable length) when calculating the total wire length (+ and – wire).

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

26/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

23.7. PARALLEL USE TO INCREASE OUTPUT POWER
Unit A

Power supplies from the same series (Q-Series) can be paralleled to increase the output
power. The output voltage shall be adjusted to the same value (±100mV) with the sameload conditions on all units, or the units can be left with the factory settings.

AC

If more than three units are connected in parallel, a fuse or circuit breaker with a rating of
30A or 32A is required on each output. Alternatively, a diode or redundancy module canalso be utilized.

+
-

DC

+

Unit B

Load

AC

Keep an installation clearance of 15mm (left / right) between two power supplies andavoid installing the power supplies on top of each other. Do not use power supplies inparallel in mounting orientations other than the standard mounting orientation (input
terminals on bottom and output terminals on the top of the unit) or in any other condition
where a derating of the output current is required (e.g. altitude, above 60°C, …).

DC

+
-

-

Pay attention that leakage current, EMI, inrush current, harmonics will increase when using multiple power supplies.

23.8. PARALLEL USE FOR REDUNDANCYPower supplies can be paralleled for redundancy to gain higher system availability. Redundant systems require a certain amount of extra
power to support the load in case one power supply unit fails. The simplest way is to put two power supplies in parallel. This is called a
1+1 redundancy. In case one power supply unit fails, the other one is automatically able to support the load current without any
interruption. Redundant systems for a higher power demand are usually built in a
24V
Failure20A
N+1 method. E.g. five power supplies, each rated for 20A are paralleled to build an
MonitorLoad
80A redundant system. For N+1 redundancy the same restrictions apply as forincreasing the output power, see also chapter 23.7.
Please note: This simple way to build a redundant system does not cover failures
such as an internal short circuit in the secondary side of the power supply. In such acase, the defective unit becomes a load for the other power supplies and theoutput voltage can not be maintained any more. This can be avoided by utilizing
decoupling diodes or Mosfets, which are included in the redundancy module
YR40.241 or YR40.242.

++ - -

DC24V,20A OK

QS20.241
Power
SupplyRecommendations for building redundant power systems:
a)
b)
c)

Use separate input fuses for each power supply.
Monitor the individual power supply units. Therefore, use the DC-OK relay
contact of the QS20 power supply.
It is desirable to set the output voltages of all units to the same value (±100mV) or leave it at the factory setting.

L N PE+-

OutputYR40.242* )Redundancy
ModuleInput Input
12+ - + -++ - -

DC24V,20A OK

QS20.241
Power
SupplyL N PE* ) YR40.241

I

also possible

I

L
N
PE

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

27/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series

23.9. SERIES OPERATION

Unit A

Power supplies of the same type can be connected in series for higher output voltages.
It is possible to connect as many units in series as needed, providing the sum of theoutput voltage does not exceed 150Vdc. Voltages with a potential above 60Vdc are not
SELV anymore and can be dangerous. Such voltages must be installed with a protection
against touching.

AC

Earthing of the output is required when the sum of the output voltage is above 60Vdc.

AC

DC

+
+

Unit B

Avoid return voltage (e.g. from a decelerating motor or battery) which is applied to the
output terminals.

DC

Load

+
-

Earth
(see notes)

Keep an installation clearance of 15mm (left / right) between two power supplies andavoid installing the power supplies on top of each other. Do not use power supplies in series in mounting orientations other than thestandard mounting orientation (input terminals on bottom and output terminals on the top of the unit).
Pay attention that leakage current, EMI, inrush current, harmonics will increase when using multiple power supplies.

23.10. INDUCTIVE AND CAPACITIVE LOADSThe unit is designed to supply any kind of loads, including unlimited capacitive and inductive loads.

23.11. OPERATION ON TWO PHASESPower Supply
L1
240V +15% max.

The power supply can also be used on two-phases of a three-phase-system. Such aphase-to-phase connection is allowed as long as the supplying voltage is below
240V+15%. Use a fuse or a circuit breaker to protect the N input. The N input is internallynot protected and is in this case connected to a hot wire. Appropriate fuses or circuit
breakers are specified in chapter 23.4 “External Input Protection”.

L3

AC
L
Fuse

internal
fuse

N
PE

L2

DC

23.12. USE IN A TIGHTLY SEALED ENCLOSURE
When the power supply is installed in a tightly sealed enclosure, the temperature inside the enclosure will be higher than outside. In
such situations, the inside temperature defines the ambient temperature for the power supply.
The following measurement results can be used as a reference to estimate the temperature rise inside the enclosure.
The power supply is placed in the middle of the box, no other heat producing items are inside the box
Enclosure:
Load:
Input:
Temperature inside enclosure:
Temperature outside enclosure:
Temperature rise:

Rittal Typ IP66 Box PK 9522 100, plastic, 254x180x165mm
24V, 16A; (=80%) load is placed outside the box
230Vac49.2°C (in the middle of the right side of the power supply with a distance of 2cm)
24.4°C
24.8K

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

28/29

QS20.241, QS20.241-A1, QS20.241-C1
24V, 20A, SINGLE PHASE INPUT

Q-Series23.13. MOUNTING ORIENTATIONSMounting orientations other than input terminals on the bottom and output on the top require a reduction in continuous output power
or a limitation in the maximum allowed ambient temperature. The amount of reduction influences the lifetime expectancy of the power
supply. Therefore, two different derating curves for continuous operation can be found below:
Curve A1 Recommended output current.
Curve A2 Max. allowed output current (results in approximately half the lifetime expectancy of A1).
Fig. 23-6
Mounting
Orientation A(Standardorientation)

Output Current
OUTPUT

20A
16
12
8
4
0
10

Power
SupplyINPUT

Fig. 23-7
Mounting
Orientation B(Upside down)

20

30

40

50

60°C

INPUT

20A
16
12
8
4
0
10

A2
A1
Ambient Temperature

20

30

40

50

60°C

Pow er
SupplyOUTPUT

Output Current

20A
16
12
8
4
0
10

A2
A1
Ambient Temperature

20

30

40

50

60°C

Output Current

OUTPUT

Pow er
Supply

INPUT

20A
16
12
8
4
0
10

A2
A1
Ambient Temperature

20

30

40

50

60°C

INPUT

Pow er
SupplyOutput Current

OUTPUT

Fig. 23-10
Mounting
Orientation E(Horizontal ccw)

Ambient Temperature

Output Current

Fig. 23-8
Mounting
Orientation C(Table-top
mounting)

Fig. 23-9
Mounting
Orientation D(Horizontal cw)

A1

20A
16
12
8
4
0
10

A2
A1
Ambient Temperature

20

30

40

50

60°C

Aug. 2023 / Rev. 2.4 DS-QS20.241-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

29/29