QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

POWER SUPPLY
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AC 200-240V Input
Width only 70mm
Efficiency up to 94.5%
Very Low No-load Losses
150% (720W) Peak Load Capability
Safe HiccupPLUS Overload Mode
Easy Fuse Tripping due to High Overload Current
Full Power Between -25°C and +60°C
DC-OK Relay Contact
Quick-connect Spring-clamp Terminals
3 Year Warranty

GENERAL DESCRIPTIONSHORT-FORM DATA

The most outstanding features of this Dimension QSeries DIN-rail power supply are the high efficiency andthe small size, which are achieved by a synchronousrectification and further novel design details.

Output voltage
Adjustment range
Output current

The QS20.244 is a device for 200-240V non-public mains
only. This supports regional applications and offers
additional cost and space savings. If a wide-range unit
with PFC is preferred, choose the QS20.241.
With short-term peak power capability of 150% andbuilt-in large sized output capacitors, these features
help start motors, charge capacitors and absorb reverse
energy and often allow a unit of a lower wattage class
to be used. Diagnostics are easy due to the dry DC-ok
contact, a green DC-ok LED and red overload LED.
High immunity to transients and power surges as well as
low electromagnetic emission makes usage in nearly
every environment possible.
Unique quick-connect spring-clamp terminals allow asafe and fast installation and a large international
approval package for a variety of applications makes
this unit suitable for nearly every situation.

ORDER NUMBERS

DC 24V24 - 28V
20 – 17A
30 – 26A
Output power
480W
720W
Output ripple< 100mVpp
Input voltage
AC 200-240V
Mains frequency
50-60HzAC Input current
4.45A
Power factor
0.5
AC Inrush current
typ. 40A peak
Efficiency
94.5%
Losses28.3W
Temperature range -25°C to +70°C
Derating
12W/°C
Hold-up time
typ. 46ms
Dimensions
70x124x127mm

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

MARKINGSPower Supply

QS20.244

24-28V Standard unit

Accessory

ZM1.WALL
YR40.242
YR40.245

Wall mount bracket
Redundancy module
Redundancy module

IND. CONT. EQ.

UL 508

UL 60950-1

MarineClass I Div 2

EMC, LVD, RoHS

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

INDEX
Page
1. Intended Use .......................................................3
2. Installation Requirements...................................3
3. AC-Input...............................................................4
4. DC-Input...............................................................5
5. Input Inrush Current ...........................................5
6. Output .................................................................6
7. Hold-up Time.......................................................8
8. DC-OK Relay Contact ..........................................8
9. Efficiency and Power Losses................................910. Lifetime Expectancy and MTBF.........................10
11. Functional Diagram...........................................10
12. Terminals and Wiring........................................11
13. Front Side and User Elements...........................12
14. EMC....................................................................13
15. Environment ......................................................14
16. Protection Features ...........................................15
17. Safety Features ..................................................15
18. Dielectric Strength ............................................16
19. Approvals...........................................................16Page
20. Physical Dimensions and Weight ..................... 17
21. Accessories ........................................................ 18
21.1. ZM1.WALL Wall Mounting Bracket .......18
21.2. YR40 Redundancy Modules .....................19
22. Application Notes............................................. 20
22.1. Repetitive Pulse Loading..........................20
22.2. Peak Current Capability ...........................21
22.3. Back-feeding Loads ..................................21
22.4. External Input Protection.........................21
22.5. Charging of Batteries ...............................22
22.6. Output Circuit Breakers............................22
22.7. Parallel Use to Increase Output Power....23
22.8. Parallel Use for Redundancy ....................23
22.9. Series Operation .......................................24
22.10. Inductive and Capacitive Loads................24
22.11. Operation on Two Phases ........................24
22.12. Use in a Tightly Sealed Enclosure ............24
22.13. Mounting Orientations ............................25

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 withstandard 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 indicating flexibility of choice with no implied preference.

shall

A key word indicating a mandatory requirement.

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

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

1. INTENDED USEThis device is designed for installation in an enclosure and is intended for the general use such as in industrial control,
office, communication, and instrumentation equipment. The power supply is suitable for application, where a power
factor correction according to EN 61000-3-2 is not needed. See also section 14.
Do not use this power supply in equipment, where malfunction may cause severe personal injury or threaten humanlife.
This device is designed for use in hazardous, non-hazardous, ordinary or unclassified locations.

2. INSTALLATION REQUIREMENTS
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.
Mount the unit on a DIN-rail so that the output terminals are located on the top and the input terminals are locatedon the bottom of the unit. For other mounting orientations see de-rating requirements in this document. See chapter
22.13.
This device is designed for convection cooling and does not require an external fan. Do not obstruct airflow and do
not cover ventilation grid (e.g. cable conduits) by more than 30%!
Keep the following installation clearances: 40mm on top, 20mm on the bottom, 5mm on the left and right sides arerecommended when the device is loaded permanently with more than 50% of the rated power. Increase this clearance
to 15mm in case the adjacent device is a heat source (e.g. another power supply).
A disconnecting means shall be provided for the output of the power supplies when used in applications according to
CSA C22.2 No 107.1-01.

WARNING

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

- Do not use the power supply without proper grounding (Protective Earth). Use the terminal on the input block forearth connection and not one of the screws on the housing.
- Turn power off before working on the device. Protect against inadvertent re-powering.
- Make sure that the wiring is correct by following all local and national codes.
- Do not modify or repair the unit.
- Do not open the unit as high voltages are present inside.
- Use caution to prevent any foreign objects from entering 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 surfaces may cause burns.
Notes for use in hazardous location areas:
The power supply is suitable for use in Class I Division 2 Groups A, B, C, D locations.
WARNING EXPLOSION HAZARDS!
Substitution of components may impair suitability for this environment. Do not disconnect the unit or operate thevoltage adjustment unless power has been switched off or the area is known to be non-hazardous.
A suitable enclosure must be provided for the end product which has a minimum protection of IP54 and fulfils therequirements of the EN 60079-15.

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

3. AC-INPUT
AC input
AC input range
Allowed voltage L or N to earth
Input frequency
Turn-on voltage
Shut-down voltage

Input current
Power factor *)Crest factor **)Start-up delay
Rise timeTurn-on overshoot

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

AC 200-240V
170-276Vac
276-300Vac
276Vac50–60Hz
155Vac110Vac

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

AC 230V
4.45A
0.5
4.2
140ms
88ms
95ms
100mV

suitable for TN-, TT- and IT mains networks
continuous operation< 500ms
continuous, IEC 62103±6%
steady-state value, see Fig. 3-1
steady-state value, see Fig. 3-1

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.

Rated
input range

max.
500ms

Turn-onShut-down

POUT

Fig. 3-2 Turn-on behavior, definitions

Input
Voltage- 5%

OutputVoltage

VIN
170V

Start-up
delay

Rise
Time

OvershootFig. 3-1 Input voltage range

276V 300Vac

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

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

5A

0.55

4

0.50

3

0.45

2

0.40
0.35

1
Output Current

0
2

4

6

8 10 12 14 16 18 20A

Output Current

0.30
2

4

6

8

10 12 14 16 18 20A

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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24V, 20A, SINGLE PHASE INPUT

Q-Series

4. DC-INPUT
Do not operate the power supply with DC-input voltage

5. INPUT INRUSH CURRENT
An active inrush current circuitry (NTC and fixed resistor which are bypassed by an IGBT after the inrush is completed)limits the input inrush current after turn-on of the input voltage.
The charging current into EMI suppression capacitors is disregarded in the first microseconds after switch-on.

Inrush current
Inrush energy

max.
typ.
max.

AC 230V
52Apeak
40Apeak
4A2sover entire temperature range; cold startover entire temperature range; cold startover entire temperature range; cold startFig. 5-1 Input inrush current, typical behavior

Input
Current

Input
Voltage

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

230Vac
24V, 20A
40°C, cold start
Input current 20A / DIVInput voltage 500V / DIV
Output voltage 20V / DIV
40ms / DIV

OutputVoltage

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
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.
min.
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 Æ 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 shortterm duration is hardware controlled by an output power manager. This BonusPower® is repeatedly available. Detailed information
can be found in chapter 22.1. If the power supply is loaded longer with the BonusPower® than shown in the Bonus-time diagram (seeFig. 6-2), the max. output power is automatically reduced to 480W. If the power requirement is continuously above 480W and thevoltage 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, the unit continuously delivers
current.
HiccupPLUS ModeAt heavy overloads (when output voltage falls below 20V), the power supply delivers continuous output current for 2s. After this, theoutput is switched off for approx. 17s before a new start attempt is automatically performed. This cycle is repeated as long as theoverload exists. If the overload has been cleared, 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 notguaranteed value which can be achieved. The typical value is about 28.5V.

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
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 bedischarged and causes a voltage dip on the output. Detailed curves can be found in chapter 22.2.
Peak current voltage dips

typ.
typ.
typ.

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

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

Fig. 6-2 Bonus time vs. output power

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

Output Voltage

28V
24

B

20
C

16

A

12
Short term <5s then auto
switching to curve B + C
B Continuously available
C Below 20Vdc hiccup mode

A

8
4
0
0

5

10

15

20

25

OutputCurrent

30

35 40A

Fig. 6-4 BonusPower® recovery time

Fig. 6-3 Short-circuit on output, hiccup mode (typ.)OutputCurrent

End ofshort circuit

Start ofshort circuit

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

Limitation by
Power Manager

Power
Demand

35A

100%
t

t

0
2s

17s

2s

17s

2s

OutputVoltage

Recovery Time
Bonus Power disabled

Bonus
Time

17s

t

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%

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

7. HOLD-UP TIME
Hold-up TimeAC 230V
94ms
46ms

typ.
typ.

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

at 24V, 10A, see Fig. 7-1
at 24V, 20A, see Fig. 7-1
Fig. 7-2 Shut-down behavior, definitions

Hold-up Time

120ms
100

a

a) 24V 10A typ.
b) 24V 10A min.
c) 24V 20A typ.
d) 24V 20A min.

Zero Transition
b

80

Input
Voltage

c
d

60

- 5%

OutputVoltage40
20
Input Voltage

0
170

200

230

Hold-up Time

264Vac8. 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 a unit 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 section 18.

Contact re-closes
Contact ratings
Isolation voltage

Fig. 8-1 DC-ok relay contact behavior
VOUT = VADJ
10%

<
1ms

open

closed>1ms

0.9* VADJ

250ms

open

closedNote: The 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 lamp 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 abattery, the power supply is used in parallel or the power supply is used for N+1 redundant systems.

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

9. EFFICIENCY AND POWER LOSSES
Efficiency
Average efficiency *)Power losses*)

AC 230V
94.5%
94.55%
4.4W
28.3W

typ.
typ.
typ.
typ.

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 the time.

Fig. 9-1

Efficiency vs. output current at 24V,
typFig. 9-2

Losses vs. output current at 24V, typ.

Efficiency

Power Losses

95%

30W

94

25

93

20

92

15

91

10

90

5
Output Current

890Fig. 9-3

4

812Output Current

0
16

20A

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

0

Fig. 9-4

4

8

12

16

20A

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

Efficiency

Power Losses

95%

35W
30

94

25
20

93

15
10

Input Voltage

92

Input Voltage

5
170

190

210

230

250 270Vac

170

190

210

230

250 270Vac

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

10. LIFETIME EXPECTANCY AND MTBF
AC 230V
62 000h
307 000h *)188 000h *)577 000h
946 000h
305 000h
409 000h

Lifetime expectancy *)MTBF **) SN 29500, IEC 61709
MTBF **) MIL HDBK 217F

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 thecapacitor’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 adevice. It is the statistical representation 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 thatstatistically one unit will fail every 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

Power
Converter

OutputFilterVOUT++
OverloadLED

Temperature
Shutdown

OutputPower
Manager

OutputOverVoltage
Protection

OutputVoltage
Monitor

DC-ok
LED
DC-ok
Relay

DC-ok
Contact

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

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 terminals
0.5-6mm2
0.5-4mm220-10 AWG
10mm / 0.4inch
2.8mm

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

Outputspring-clamp terminals
0.5-6mm2
0.5-4mm220-10 AWG
10mm / 0.4inch
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.

Fig. 12-1

DC-OK-Signal
spring-clamp terminals
0.3-4mm2
0.3-2.5mm2
26-12 AWG
6mm / 0.25inch
2.25mmConnecting 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 asshown 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

+

Load

Distribution
Terminals

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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24V, 20A, SINGLE PHASE INPUT

Q-Series

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 perpole)+
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 isrequired.

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 forapprox. 17s before a new start attempt is automatically performed. If the overload has been cleared, the device will operate normally. If theoverload 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.

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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24V, 20A, SINGLE PHASE INPUT

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14. EMCThe power supply is suitable for application, where a power factor correction according to EN 61000-3-2 is not needed(See footnote remarks). 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
Powerful transients

According generic standards: EN 61000-6-1 and EN 61000-6-2
EN 61000-4-2
contact discharge
8kV
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
LÆN2kV
L Æ PE, N Æ PE
4kV
EN 61000-4-5+Æ1kV+ / - Æ PE
1kV
EN 61000-4-5
DC-OK signal Æ PE
1kV
EN 61000-4-6
0.15-80MHz
10V
EN 61000-4-11
0% of 200Vac
0Vac, 20ms
40% of 200Vac
80Vac, 200ms
70% of 200Vac
140Vac, 500ms
EN 61000-4-11
0% of 200Vac (=0V)
5000msVDE 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 C
Criterion A

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

According generic standards: EN 61000-6-3 and EN 61000-6-4
EMC Emission
Conducted emission
EN 55011, EN 55022, FCC Part 15, CISPR 11, CISPR 22
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 55022
Class B
Harmonic input current
EN 61000-3-2
Not fulfilled **)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) thisdevice must accept any interference received, including interference that may cause undesired operation.
*) tested with constant current loads, non pulsing**) The power supply does not fulfill the harmonic current standard EN61000-3-2. The use of this unit can be limited in some applications:
A power supply has to comply with EN 61000-3-2 (Standard for harmonic input current) when:(a) the end-device is used within the European Union and(b) the end-device is connected to a public mains supply with a nominal voltage ≥ 220Vac and(c) the power supply is fitted in an end-device with an average input power in excess of 75W or fitted in an end-device with a continuous
input power in excess of 75W or part of a lighting system.
Exception: End-devices for professional applications with an input power > 1000W do not need to fulfill EN 61000-3-2.
Comments:- The average input power must be determined in accordance with EN 61000-3-2.
- Industrial mains supplies with their own transformer are considered to be “non-public”.
- Where individual self-contained items of equipment are installed in a rack or case (e.g. devices connected in parallel), they are regarded
as being individually connected to the mains supply. The rack or case need not be tested as a whole. Alternatively it is also permitted toassess the whole rack or case. This is recommended for devices used in professional applications with an input power greater than 1000W.
***) for information only, not mandatory for EN 61000-6-3****) Quasi-peak values fulfilled, average values +5dB

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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24V, 20A, SINGLE PHASE INPUT

Q-Series

The power supply has three converters with three different switching frequencies
included. One is nearly constant. The other two are input voltage and load dependent.
100kHzResonant converter, nearly constant
125kHz to 510kHz
Boost converter, input voltage and load dependent
35kHz to 45kHz
Aux. converter, input voltage and load dependent

Switching Frequencies
Switching frequency 1
Switching frequency 2
Switching frequency 3

15. ENVIRONMENT
Operational temperature *)Storage temperature
Output de-rating
Humidity **)Vibration sinusoidal
Shock
Altitude-25°C to +70°C (-13°F to 158°F)-40 to +85°C (-40°F to 185°F)
12W/°C
5 to 95% r.H.
2-17.8Hz: ±1.6mm; 17.8-500Hz: 2g
2 hours / axis
30g 6ms, 20g 11ms
3 bumps / direction, 18 bumps in total
0 to 2000m (0 to 6 560ft)
2000 to 6000m (6 560 to 20 000ft)

reduce output power according Fig. 15-1
for storage and transportation
60-70°C (140°F to 158°F)
IEC 60068-2-30
IEC 60068-2-6
IEC 60068-2-27

without any restrictions
reduce output power or ambient temperature,
see Fig. 15-2
IEC 62103, EN 50178, overvoltage category II
30W/1000m or 5°C/1000m> 2000m (6500ft), see Fig. 15-2
III
IEC 62103, EN 50178, altitudes up to 2000m
II
altitudes from 2000m to 6000m
2
IEC 62103, EN 50178, not conductive
The unit does not release any silicone or other LABS-critical substances and is suitable foruse in paint shops.

Altitude de-rating
Over-voltage category
Degree of pollution
LABS compatibility*) 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

for typ. 4s

25

30A

20

continuous

15

20

continuous

15

10

10

5

5

0
-25

for typ. 4s

25

Ambient Temperature

0

20

40

A

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

0

2000

C

Altitude0
60 70°C

B

4000

6000m

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
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 redundantmax. 37Vdc
circuit limits the maximum output voltage. The output
shuts down and automatically 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. 0.55mA / 1.56mA
230Vac, 50Hz, TN-,TT-mains / IT-mains< 0.87mA / 2.00mA
264Vac, 50Hz, TN-,TT-mains / IT-mains

double or reinforced insulation

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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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 thevoltage with a slow ramp (2s up and 2s down). 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

500Vac> 15mA> 15mA> 40mA> 1mA

Fig. 18-1 Dielectric strength

Input

DC-ok
B*)

L
N

Cut-off current setting
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 ofthe output circuit shall be connected to the protective earthsystem. 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.

19. APPROVALSEC Declaration of Conformity

The CE mark indicates conformance with the- EMC directive 2004/108/EC,- Low-voltage directive (LVD) 2006/95/EC and- RoHS directive 2011/65/EU
CB Scheme,
Information Technology Equipment

IEC 60950-1
2nd Edition
UL 508IND. CONT. EQ.

UL 60950-1
2nd Edition

ANSI / ISA 12.12.01-2007(Class I Div 2)
MarineGOST P

Listed for use as Industrial Control Equipment;
U.S.A. (UL 508) and Canada (C22.2 No. 107-1-01);
E-File: E198865
Recognized for use as Information Technology Equipment,
Level 5; U.S.A. (UL 60950-1) and Canada (C22.2 No. 60950-1);
E-File: E137006
Applicable for altitudes up to 2000m.
Recognized for use in Hazardous Location Class I Div 2 T4Groups A,B,C,D systems; U.S.A. (ANSI / ISA 12.12.01-2007) andCanada (C22.2 No. 213-M1987)
GL (Germanischer Lloyd) classified andABS (American Bureau for Shipping) PDA
Environmental category: C, EMC2Marine and offshore applications
Certificate of Conformity for Russia and other GUS countries

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

20. PHYSICAL DIMENSIONS AND WEIGHT
WeightDIN-Rail

Installation Clearances

880g / 1.94lb
Use 35mm DIN-rails according to EN 60715 or EN 50022 with a height of 7.5 or 15mm.
The DIN-rail height must be added to the unit depth (127mm) to calculate the total required
installation depth.
See chapter 2

Fig. 20-1 Front viewFig. 20-2 Side viewOct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

21. ACCESSORIES

21.1. ZM1.WALL WALL MOUNTING BRACKETThis bracket is used to mount the power
supply onto a flat surface without utilizing
a DIN-Rail.

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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24V, 20A, SINGLE PHASE INPUT

Q-Series

21.2. YR40 REDUNDANCY MODULES
YR40.242 – (2x 20A Inputs, 1x 40A output)
The YR40.242 is equipped with two input channels, which are individually decoupled byutilizing mosfet technology. Using mosfets instead of diodes reduces the heat generation andthe voltage drop between input and output. The YR40.242 does not require an additional
auxiliary voltage and is self-powered even in case of a short circuit across the output.
Due to the low power losses, the unit is very slender and only requires 46mm width on the
DIN-rail.

YR40.245 – (1x 40A input, 1x 40A output)
The YR40.245 is a 40A single channel redundancy module, which is equipped with a plugconnector 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 and output. It does not require an additional auxiliary voltage and is selfpowered even in case of a short circuit across the output.

Fig. 21-2 Typical N+1 or 1+1 Redundant configuration for 20A withmultiple YR40.245 redundancy modules

Fig. 21-1 Typical 1+1 Redundant configurationfor 20A with a dual redundancy module
24V
20A
Load

FailureMonitorFailureMonitor

24V
20A
Load

-

+
++ - -

DC24V,20A OK

QS20.244
Power
SupplyL N PE+-

OutputYR40.242*)
Redundancy
ModuleQS20.244
Power
SupplyQS20.244
Power
SupplyL
N
PE

also possible

YR40.245
Redundancy
ModuleL N PEL N PE+ - + -

QS20.244
Power
Supply+YR40.245
Redundancy
ModuleInput-

L N PE

+

-

I

I

I

OutputDC24V,20A OK

Input

Input Input
1
2*) YR40.241

I++ - -

DC24V,20A OK

DC24V,20A OK-+

Output++ - -++ - -

L
N
PE

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

22. APPLICATION NOTES
22.1. REPETITIVE PULSE LOADING
Typically, a load current is not constant and varies over time. This power supply is designed to support loads with ahigher short-term power demand (=BonusPower®). The short-term duration is hardware controlled by an output
power manager and is available on a repeated 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 section)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 themaximum duty cycle curve (Fig. 22-2) to check if the average output current is below the nominal current.
Fig. 22-1 Repetitive pulse loads, definitions

Fig. 22-2 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 the max. 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=

- Max. repetition rate = pulse +pause length = 2.7s

Tpeak - (DutyCycle x Tpeak)
DutyCycle=

1s - (0.37 x 1s)
0.37= 1.7sMore 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

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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24V, 20A, SINGLE PHASE INPUT

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22.2. 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 pick-up 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 a certain 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 thepower supply can deliver extra current. Discharging this capacitor causes a voltage dip on the output. The following
two examples show typical voltage dips:
Fig. 22-3 Peak load with 2x the nominal
current for 50ms, typ.

Fig. 22-4 Peak load with 5x the nominal
current for 5ms, typ.

24V
OutputVoltage

24V
40A

OutputVoltage

100A

20V

OutputCurrent

0A

16V

OutputCurrent

0A

10ms/DIV

1ms/DIV

Peak 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.

22.3. 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.

22.4. 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 an ampacity 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 6A C-Characteristic breaker should be used

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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22.5. 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 switchedoff (except in case a blocking diode is utilized).

22.6. OUTPUT CIRCUIT BREAKERS
Standard miniature circuit breakers (MCB’s or UL1077 circuit breakers) are commonly used for AC-supply systems andmay also be used on 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 size that 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, afast (magnetic) tripping of the MCB is desired. A quick shutdown within 10ms is necessary corresponding roughly tothe ride-through time of PLC's. This requires power supplies with high current reserves and large output capacitors.
Furthermore, the impedance of the faulty branch must be 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 crosssection and wire length.
Fig. 22-5 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
1.0mm²1.5mm²2.5mm²
26m
35m
62m
82m
C-2A
23m
29m
54m
72m
C-3A
15m
19m
31m
51m
C-4A
7m
10m
15m
26m
C-6A
5m
7m
10m
16m
C-8A
2m
3m
5m
7m
C-10A
1m
2m
C-13A
19m
27m
38m
57m
B-6A
7m
11m
14m
23m
B-10A
1m
2m
3m
5m
B-13A

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

Oct. 2013 / Rev. 2.2 DS-QS20.244-EN
All parameters are specified at 24V, 20A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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22.7. 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 same load 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 breakerwith a rating of 30A or 32A is required on each output. Alternatively, a diodeor redundancy module can also be utilized.

Unit B

DC

AC

+
+
Load

+
-

-

Keep an installation clearance of 15mm (left / right) between two powerDC
supplies and avoid installing the power supplies on top of each other. Do not
use power supplies in parallel 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, …).
Pay attention that leakage current, EMI, inrush current, harmonics will increase when using multiple power supplies.

22.8. PARALLEL USE FOR REDUNDANCYPower supplies can be paralleled for redundancy to gain higher system availability. Redundant systems require acertain 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
24V
Failureinterruption. Redundant systems for a higher power demand are
20A
MonitorLoadusually built in a N+1 method. E.g. five power supplies, each rated
for 20A are paralleled to build a 80A redundant system. For N+1
redundancy the same restrictions apply as for increasing the output
power, see also section 22.7.
Please note: This simple way to build a redundant system does notcover failures such as an internal short circuit in the secondary sideof the power supply. In such a case, the defective unit becomes aload for the other power supplies and the output 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+-

Output++ - -

DC24V,20A OK

YR40.242*)
QS20.244
Power
SupplyL N PE

Redundancy
ModuleQS20.244
Power
SupplyInput Input
1
2

L N PE+ - + -

Recommendations 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 samevalue (± 100mV) or leave it at the factory setting.

*) YR40.241

I

also possible

I

L
N
PE

Oct. 2013 / Rev. 2.2 DS-QS20.244-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 0Germany

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QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

Unit A

22.9. SERIES OPERATIONACPower 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 the output voltage does not exceed 150Vdc. Voltages
with a potential above 60Vdc are not SELV any more and can be dangerous.
Such voltages must be installed with a protection against touching.

DC

+
+

Unit BAC

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

DC

Load

-

+
-

Earth
(see notes)

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

Keep an installation clearance of 15mm (left / right) between two power supplies and avoid installing the power
supplies on top of each other. Do not use power supplies in series in mounting orientations other than the standard
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.

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

22.11. 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 a phase-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 internally not protected and is in this case connected toa hot wire. Appropriate fuses or circuit breakers are specified in section 22.4
“External Input Protection”.

L3

AC
L
Fuse

L2

internal
fuse

N
PE
DC

22.12. 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
230Vac48.2°C (in the middle of the right side of the power supply with a distance of 2cm)
24.7°C
23.5K

Oct. 2013 / Rev. 2.2 DS-QS20.244-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 0Germany

24/25

QS20.244
24V, 20A, SINGLE PHASE INPUT

Q-Series

22.13. MOUNTING ORIENTATIONSMounting orientations other than input terminals on the bottom and output on the top require a reduction incontinuous 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
Curve A2

Recommended output current.
Max allowed output current (results in approximately half the lifetime expectancy of A1).

Fig. 22-6
Mounting
Orientation A(Standardorientation)

Output Current

OUTPUT

20A
16
12
8
4
0
10

Power
SupplyINPUT

Fig. 22-7
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

Power
SupplyOUTPUT

Output Current

20A
16
12
8
4
0
10

A2
A1

Ambient Temperature

20

30

40

50

60°C

Output Current

OUTPUT

Power
Supply

INPUT

20A
16
12
8
4
0
10

A2
A1

Ambient Temperature

20

30

40

50

60°C

INPUT

Power
SupplyOutput Current

OUTPUT

Fig. 22-10
Mounting
Orientation E(Horizontal ccw)

Ambient Temperature

Output Current

Fig. 22-8
Mounting
Orientation C(Table-top
mounting)

Fig. 22-9
Mounting
Orientation D(Horizontal cw)

A1

20A
16
12
8
4
0
10

A2
A1

Ambient Temperature

20

30

40

50

60°C

Oct. 2013 / Rev. 2.2 DS-QS20.244-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 0Germany

25/25