QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

DC/DC CONVERTER
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EN 50155 Railway Compliant
Conformal Coated PC-boards
Quick-connect Spring-clamp Terminals
77-154Vdc Wide-range Input
Width only 40mm
Efficiency up to 91.1%
Excellent Partial Load Efficiency
Minimal Inrush Current Surge
Full Power Between -25°C and +70°C
DC-OK Relay Contact
Reverse Input Polarity Protected
3 Year Warranty

GENERAL DESCRIPTIONSHORT-FORM DATAThe QS5.241-60 DC/DC converter is designed specificallyfor railway & transportation applications. It is approved
according to the EN 50155 standard, which is aninternational standard covering electronic equipmentused on rolling stock for railway applications. The
standard covers aspects such as temperature, humidity,
shock, vibration, EMI and other parameters. Because of
these requirements, the unit is equipped with
conformal coated pc-boards.

Output voltage
Adjustment range
Output current

The unit features a DC-OK signal contact for remotemonitoring, and quick-connect spring-clamp terminals
for a reliable connection even when mechanicalvibration and shock are involved. The unit also covers an
extreme wide temperature range from -25°C up to+70°C with full output current.
This DC/DC converter comes in a very compact housing
and requires only 40mm space on the DIN-rail due tothe high efficiency and low power losses. The highefficiency is achieved by utilizing cutting edge
technology and other unique design techniques.

ORDER NUMBERS

DC 24V24 - 28V
4.2 – 3.6A
6.3 – 5.4A
Output power
100W
150W
Output ripple
max. 50mVpp
AC Input voltage
DC Input voltage
DC 110V
DC Input current
1.0A
Inrush current
typ. 10A peak
Efficiency
91.1%
Losses
9.8W
Temperature range -25°C to +70°C
Derating
Hold-up time
typ. 42ms
Dimensions
40x124x117mm
Weight640g / 1.41lb

continuous
for typ. 4s
continuous
for typ. 4s
20Hz to 20MHz- 30%/ +40%
at 110Vdc
at 110Vdc
at 110Vdc
at 110Vdc
operational
not required
at 110Vdc
WxHxD

MARKINGS

DC/DC converter QS5.241-60
Accessory

ZM12.SIDE
YR2.DIODE
UF20.241

Side mount bracket
Redundancy module
Buffer module

EMC, LVD

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

INDEX
Page
1. Intended Use .......................................................3
2. Installation Requirements...................................3
3. AC-Input...............................................................4
4. DC-Input...............................................................4
5. Input Inrush Current ...........................................5
6. Output .................................................................6
7. Hold-up Time.......................................................8
8. DC-OK Relay Contact ..........................................99. Efficiency and Power Losses..............................10
10. Lifetime Expectancy and MTBF.........................10
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. Approvals and Declarations..............................18Page
20. RoHS, REACH and Other Fulfilled Standards .. 18
21. Physical Dimensions and Weight ..................... 19
22. Accessories ........................................................ 20
22.1. ZM12.SIDE - Side Mounting Bracket........20
22.2. UF20.241 Buffer Module ..........................20
22.3. YR2.DIODE Redundancy Module .............21
23. Application Notes............................................. 2223.1. Repetitive Pulse Loading..........................2223.2. Peak Current Capability ...........................23
23.3. Inductive and Capacitive Loads................23
23.4. External Input Protection.........................24
23.5. Charging of Batteries ...............................24
23.6. Parallel Use to Increase Output Power....24
23.7. Parallel Use for Redundancy ....................25
23.8. Series Operation .......................................25
23.9. Back-feeding Loads ..................................26
23.10. Use in a Tightly Sealed Enclosure ............26
23.11. Mounting Orientations ............................27

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.

DC 110V

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)

110VdcA figure with the unit (Vdc) at the end is a momentary figure without any additional
tolerances included.

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.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

1. INTENDED USEThis device is designed for installation in an enclosure and is intended for the general professional use such as inrolling stock for railway applications or in industrial control, office, communication, and instrumentation equipment.
Do not use this DC/DC converter in equipment, where malfunction may cause severe personal injury or threaten
human life.

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 input terminals are located on the bottom of the unit. For other mounting
orientations see de-rating requirements in this document. See chapter 23.11.
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 15%!
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).

WARNING

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

- Do not use the DC/DC converter without proper grounding (Protective Earth). Use the terminal on the input blockfor earth 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.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

3. AC-INPUT
Do not operate this DC/DC converter with an AC-input voltage. Use the QS10.241 or QS10.241-C1 unit instead.

4. DC-INPUT
Use a battery or a similar DC source. A supply from the intermediate DC-bus of a frequency converter is notrecommended and can cause a malfunction or damage the unit.
Input voltage
Input voltage range

nom.

Input current
Allowed voltage between input
to earth (ground)

typ.
max.

DC 110V
77-154Vdc
66-77Vdc
1.0A
375VdcSlew rate for voltage between
input to earth (ground)
Allowed input ripple voltage

max.

± 600V
1000V/μs

Shut-down voltage
Start-up delay
Rise timeTurn-on overshootExternal input protection

Rated
input range

50Hz –10kHz
10kHz – 50kHz
typ.
steady-state value, at ambient temperatures between-20°C and +70°C, see Fig. 4-1
typ.
63Vdc
steady-state value, see Fig. 4-1
typ.
120ms
see Fig. 4-2
typ.
18ms
at 4.2A constant current load, 0mF load capacitance,
see Fig. 4-2
typ.
38ms
at 4.2A constant current load, 5mF load capacitance,
see Fig. 4-2
max.
100mV
see Fig. 4-2
See recommendations in chapter 23.4.
Fig. 4-2 Turn-on behavior, definitions
max.
500ms

Turn-onShut-down

peak value, allowed for transients

15Vpp
3Vpp
73Vdc

Fig. 4-1 Input voltage range

POUT

short term for 100ms
at 8.3A and 110Vdc input voltage, see Fig. 4-3
continuous, IEC 62103

Input
Voltage

OutputVoltage

VIN
77V

154V

- 5%
Start-up
delay

Rise
Time

OvershootTurn-on voltage

max.

-30%/+40%

375VdcAug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

Fig. 4-3 Input current vs. output load at 24V
output voltage
Input Current at 110Vdc input, typ.

1A
0.75
0.5
0.25
0

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5A
Output Current

5. INPUT INRUSH CURRENT
An active inrush limitation circuit 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.

20Apeak
10Apeak
1A2s

at 110Vdc, temperature independent
at 110Vdc, temperature independent
at 110Vdc, temperature independentFig. 5-1 Typical input inrush current behaviour at nominal load and
25°C ambient

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

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

Output power
BonusPower® time

BonusPower® recovery time
Overload behaviour
Short-circuit current

**)
***)

24V
24-28V
30V ***)
24.1V
20mV
100mV
50mVpp
4.2A
3.6A
6.3A *)

nom.

5.4A *)

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

100W
150W *)
4s
3s
5s
7s
cont. current
4A **)
7A **)
8A **)
13A **)
7A **)
3 500μF

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

Output capacitance
*)

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

guaranteed
at clockwise end position of potentiometer±0.2%, at full load, cold unit
77-154Vdc
static value, 0A Æ 4.2A
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, see Fig. 6-3
continuous, load impedance 100mOhm, see Fig. 6-1
continuous, load impedance 100mOhm, see Fig. 6-1
during BonusPower® *), load impedance 100mOhm
during BonusPower® *), load impedance 100mOhm
continuous, load impedance <10mOhm, see Fig. 6-1
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 23.1. 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 100W.
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 aguaranteed value, which can be achieved. The typical value is about 28.6V.

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

Bonus Time

Adjustment
Range

28V
24

shor

16
12
8

m
t-ter

continuous

20

OutputCurrent

4
0
0

2

4

6

8

Fig. 6-2 Bonus time vs. output power

10A

10s
9
8
7
6
5
4
3
2
1
0
110

max

typ

min
Output Power

120

130

140

150

160%

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

Fig. 6-3 BonusPower® recovery time
Limitation by
Power Manager

Power
Demand100%t

OutputVoltage

Bonus
Time

Recovery Time
Bonus Power disabledt

The BonusPower® is available as soon as power comes on and immediately after the end of an output short circuit or
output overload.
Fig. 6-4 BonusPower® after input turn-on

Short ofOutput

Input
Voltage

OutputVoltage

OutputVoltage150%
OutputPower

Fig. 6-5 BonusPower® after output short

100%

Bonus
Power

Output
Power

150%

Bonus
Power

100%

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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7/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

7. HOLD-UP TIME
The internal capacitor, which supplies the energy for the hold-up time is isolated by a diode to the input voltage. A
short on the input line does not discharge the internal hold-up capacitor.
Hold-up Time

typ.
min.
typ.
min.

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

83ms
59ms
42ms
30ms

at 2.1A, see Fig. 7-1
at 2.1A, see Fig. 7-1
at 4.2A, see Fig. 7-1
at 4.2A, see Fig. 7-1
Fig. 7-2 Shut-down behavior, definitions

Hold-up Time

100ms
24V, 2.1A, typ.

75

Input
Voltage

24V, 2.1A, min.

50

24V, 4.2A, typ.
24V, 4.2A, min.

25

- 5%

OutputVoltage
Hold-up Time

Input Voltage

0
90

120

155

190

230VacAug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

8. DC-OK RELAY CONTACT
This feature monitors the output voltage, which is produced by the DC/DC converter itself. It is independent of a backfed voltage from a unit connected in parallel to the DC/DC converter 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

Note:
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 beon and the DC-ok contact will be open. The overload signal will only shutoff as soon as the adjusted voltage is reached. This is an importantcondition to consider particularly, if the load is a battery, the power
supply is used in parallel or the power supply is used for N+1 redundant
systems.

closedAug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

9. EFFICIENCY AND POWER LOSSES
Efficiency
Average efficiency*)

typ.
typ.

91.1%
88.9%

Power losses

typ.
typ.
typ.

4.0W
6.5W
9.8W

*)

at 110Vdc input and 24V, 4.2A
25% at 1.05A, 25% at 2.1A,
25% at 3.15A. 25% at 4.2A
at 110Vdc input and 24V, 0A
at 110Vdc input and 24V, 2.1A (= 50% load)
at 110Vdc input and 24V, 4.2A

The average efficiency is an assumption for a typical application where the DC/DC converter 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,
typ.

Fig. 9-2 Losses vs. output current, at 24V, typ.

Efficiency

Power Losses

92%
91
90
89
88
87
86
85
Output Current
84
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5A

12W
10
8
6
4
2
Output Current

0

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5A

10. LIFETIME EXPECTANCY AND MTBF
Lifetime expectancy*)

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

196 000h*)
535 000h*)
127 000h*)
360 000h*)
956 000h
1 619 000h
382 000h
515 000h
87 000h
115 000h

at 24V, 2.1A and 40°C
at 24V, 2.1A and 25°C
at 24V, 4.2A and 40°C
at 24V, 4.2A and 25°C
at 24V, 4.2A and 40°C
at 24V, 4.2A and 25°C
at 24V, 4.2A and 40°C, Ground Benign GB40
at 24V, 4.2A and 25°C, Ground Benign GB25
at 24V, 4.2A and 40°C, Ground Fixed GF40
at 24V, 4.2A and 25°C, Ground Fixed GF25*)

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.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

10/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

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

Reverse Polarity
and Back-feeding
Protection

Input Fuse
Input Filter
Active Inrush
LimiterTemperature
Shutdown

Boost
Converter(preconditioning)

OutputPower
Manager

OutputOverVoltage
Protection

Power
Converter

OutputVoltage
Monitor

OutputFilterVOUT++
Overload
LED
DC-ok
LED

DC-ok
Relay

DC-ok
contact

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

11/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

12. TERMINALS AND WIRING
The terminals are IP20 finger safe constructed and suitable for field- and factory wiring. Shipped in open position.
Input
Bi-stable, spring-clamp
terminals
max. 6mm2
max. 4mm2
20-10 AWG
10mm / 0.4inch
not applicable
not applicable

Type
Solid wire
Stranded wire
American Wire Gauge
Wire stripping length
Screwdriver
Recommended tightening torqueOutputBi-stable, spring-clamp
terminals
max. 4mm2
max. 2.5mm2
26-12 AWG
6mm / 0.25inch
not applicable
not applicable
Fig. 12-1

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.
d) Ferrules are allowed.

DC-OK-Signal
Bi-stable, spring-clamp
terminals
max. 4mm2
max. 2.5mm2
26-12 AWG
6mm / 0.25inch
not applicable
not applicable
Connecting a wire

1. Insert the wire

2. Close the lever

To disconnect wire:
reverse the procedure

Daisy chaining:
Daisy chaining (jumping from one DC/DC converter output to the next) is allowed as long as the average output
current through one terminal pin does not exceed 13A. 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 13A!

OutputOutput

+ + -

+ + -

-

-

+

-

Load

OutputOutput

+ + -

+ + -

-

-

DC/DC
Converter

DC/DC
Converter

DC/DC
Converter

DC/DC
Converter

Input

Input

Input

Input

+

Distribution
Terminals

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

-

Load

12/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

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

Input Terminals (Quick-connect spring-clamp terminals)+
Positive input–
Negative (return) 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 isrequiredFlashing, when the unit has switched off due to over-temperature.

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

Overload LED
OFF
OFF
ON
ON
Intermitted
OFF

DC-OK LED
ON
ON
OFF
OFF
OFF
OFF

DC-OK Contact
ClosedClosed
Open
Open
Open
Open

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

13/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

14. EMCThe DC/DC converter is suitable for rolling stock railway applications, for applications in industrial environment as wellas in residential commercial and light industry environment without any restrictions.
According generic standards: EN 61000-6-1 and EN 61000-6-2 andaccording to EN 50121-3-2
Electrostatic discharge
EN 61000-4-2
contact discharge
8kV
air discharge
15kVElectromagnetic RF field
EN 61000-4-3
80MHz-2.7GHz
20V/m
Fast transients (Burst)
EN 61000-4-4
input lines
4kV
output lines
2kV
DC-OK signal (coupling clamp)
2kV
Surge voltage on input
EN 61000-4-5+Æ2kV+ Æ PE, - Æ PE
4kV
Surge voltage on output
EN 61000-4-5+Æ0.5kV+ / - Æ PE
1kV
Surge voltage on DC-OK
EN 61000-4-5
DC-OK signal Æ PE
1kV
Conducted disturbanceEN 61000-4-6
0.15-80MHz
10V
Power – Frequency magnetic EN 61000-4-8
16.7Hz, 50Hz
100A/mfield
Power – Frequency magnetic EN 61000-4-8
0Hz
300A/mfield
Pulsed magnetic field
EN 61000-4-9
300A/mEMC Immunity

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 A
Criterion A

Criterions:
A: DC/DC converter shows normal operation behavior within the defined limits.

According generic standards: EN 61000-6-3 and EN 61000-6-4
and according to EN 50121-3-2
Conducted emission
CISPR 16-1-2, CISPR 16-2-1
limits for EN 50121-3-2 fulfilled,
input lines
limits for DC power port
according EN 61000-6-3 fulfilled
Conducted emission
CISPR 16-1-2, CISPR 16-2-1
limits for EN 50121-3-2 fulfilled,
output lines
limits for DC power port
according EN 61000-6-3 fulfilled
Radiated emission
EN 55011, EN 55022, EN 50121-3-2Class B
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.
EMC Emission

Switching Frequencies
Switching frequency 1
Switching frequency 2
Switching frequency 3

The power supply has three converters with three different switching frequencies
included. Two are nearly constant. The other one is input voltage and load dependent.
110kHznearly constant
400kHznearly constant
55kHz to 500kHz
input voltage and load dependentAug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

15. ENVIRONMENT
Conformal coating
Operational temperature*)Vibration broadband

yes-25°C to +70°C (-13°F to 158°F)-40°C+70°C to +85°C (185°F to 185°F)-40 to +85°C (-40°F to 185°F)
not required
5 to 95% r.h.
2-17.8Hz: ±1.6mm; 17.8-500Hz: 2g***)2 hours / axis
1.01grms for 10 minutes; 5-150Hz***)Vibration broadband

5.72grms for 300 minutes; 5-150Hz***)Shock

30g 6ms, 20g 11ms, 50g 30ms***)3 bumps / direction, 18 bumps in total
50g 30ms***)3 bumps / direction, 18 bumps in total
0 to 2000m (0 to 6 560ft)
2000 to 6000m (6 560 to 20 000ft)

Storage temperature
Output de-rating
Humidity **)Vibration sinusoidal

Shock

all pc-boards are conformal coatedcontinuous operation, see Fig. 15-1
start-up tested
for maximal 10 minutes every hourfor storage and transportation
see Fig. 15-1.
IEC 60068-2-30
IEC 60068-2-6; DC/DC converter in operation
IEC 60068-2-64, DC/DC converter in operation;
Tests limits according to EN 61373
IEC 60068-2-64, DC/DC converter not in
operation; Tests limits according to EN 61373
IEC 60068-2-27; DC/DC converter in operation

IEC 60068-2-27, DC/DC converter not in
operation; Tests limits according to EN 61373
without any restrictions
reduce output power or ambient temperature,
see Fig. 15-2
IEC 62103, EN 50178, overvoltage category II
6W/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

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***) Tested in combination with DIN-Rails according to EN 60715 with a height of 15mm and a thickness of 1.3mm and standard
orientation.
Fig. 15-1 Output current vs. ambient temp. at
24V output voltage

Fig. 15-2 Output current vs. altitude at 24V
output voltage

Allowed Output Current

Allowable Output Current
6.3A

6A

for typ. 4s

5
4

1
0
-25

6.3A for typ. 4s

5

4.2A

4.2A continuous operation

4

3
2

6A

continuous
for max. 10 minutes

3

C
B
A

A... Tamb < 70°C
B... Tamb < 60°C
C... Tamb < 50°C

2
1

0

25

50 60 70 85°C

Ambient Temperature

0
0

2000m

4000m

6000m
AltitudeAug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

16. PROTECTION FEATURES
Output protection
Output over-voltage protection

Electronically protected against overload, no-load and short-circuits*)
typ. 32Vdc
In case of an internal DC/DC converter defect, amax. 36Vdc
redundant circuit limits the maximum output voltage.
The output shuts down and automatically attempts torestart.
Degree of protection
IP 20
EN/IEC 60529
Penetration protection> 3.5mme.g. screws, small parts
Over-temperature protection
yes
Output shut-down with automatic restart
Input transient protection
MOV (Metal Oxide Varistor)
Internal input fuse
DC suitable fuse included
not user replaceable
Reverse input polarity protection yes
unit does not start, no signalling*)

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

17. SAFETY FEATURESClassification of output voltage

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 isolation to the input
I
PE (Protective Earth) connection required> 5MOhm
input to output, 500Vdc< 0.1Ohm
The leakage current which is produced by the DC/DC converter itself depends on the
input voltage ripple and need to be investigated in the final application.
For a smooth DC input voltage, the produced leakage current is less than 100μA.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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16/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

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> 10mA> 10mA> 20mA> 1mA

Fig. 18-1 Dielectric strength

Input

DC-ok
B*)

+

-

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.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

17/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

19. APPROVALS AND DECLARATIONSEC Declaration of Conformity

Railway applications - Electronicequipment used on rolling stock.
EN 50155:2007

The CE mark indicates conformance with the- EMC directive and the- Low-voltage directive
The manufacturer’s declaration indicate conformance withthe following characteristics:- Altitude category: AX (EN 50125-1 § 4.2.1)- Environmental category: T3 (EN 50155 § 4.1.2)- Interruption of voltage supply: S2 (EN 50155 § 5.1.1.2)- Supply change over: C2 (EN 50155 § 5.1.3)- Shock and vibration: Category 1, Class A and B (EN 61373)- EMI: EN 50121-3-2- Fire Classification: HL3 (EN 45545-2)

20. ROHS, REACH AND OTHER FULFILLED STANDARDSRoHS Directive

REACH Directive

Directive 2011/65/EU of the European Parliament and theCouncil of June 8th, 2011 on the restriction of the use ofcertain hazardous substances in electrical and electronicequipment.
Directive 1907/2006/EU of the European Parliament and theCouncil of June 1st, 2007 regarding the Registration,
Evaluation, Authorisation and Restriction of Chemicals(REACH)

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

18/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

21. PHYSICAL DIMENSIONS AND WEIGHT
Width
HeightDepth

WeightDIN-Rail
Housing material
Installation clearances

40mm 1.57’’
124mm 4.88’’
117mm 4.61’’
The DIN-rail height must be added to the unit depth to calculate the total required
installation depth.
640g / 1.41lb
Use 35mm DIN-rails according to EN 60715 or EN 50022 with a height of 7.5 or 15mm.
Body: Aluminium alloy
Cover: zinc-plated steel
See chapter 2

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

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

19/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

22. ACCESSORIES

22.1. ZM12.SIDE - SIDE MOUNTING BRACKETThis bracket is used to mount the DC/DC converter 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

22.2. UF20.241 BUFFER MODULE
This buffer unit is a supplementary device for DC 24V power supplies. It delivers power to bridge typical mains failures
or extends the hold-up time after turn-off
Power
Bufferof the input power. In times when the
LoadAC
SupplyUnit(s)power supply provides sufficient voltages,
the buffer unit stores energy in integrated+DCelectrolytic capacitors. In case of input
voltage fault, this energy is released again
in a regulated process. One buffer module can deliver 20A additional current.
The buffer unit does not require any control wiring. It can be added in parallel tothe load circuit at any given point. Buffer units can be added in parallel to increase
the output ampacity or the hold-up time.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

20/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series22.3. YR2.DIODE REDUNDANCY MODULE
FailureMonitor

The YR2.DIODE is a dual redundancy module, which has two diodes
as decoupling devices included. It
can be used for various purposes.
The most popular application is toconfigure highly reliable and true
redundant power supply systems.
Another interesting application is
the separation of sensitive loads
from non-sensitive loads. Thisavoids the distortion of the power
quality for the sensitive loads
which can cause controller failures.

++ - -+- +-++ - -

OutputIN 1 IN 2

Output

QS5.241-60
DC/DC-Conv.

YR2.DiodeQS5.241-60
DC/DC-Conv.

OUT+ - PE

Adj
DCok
OverloadINput+ - PE

Redundancy
ModuleAdj
DCokOverload

INput

+ -

optional
I

I

24V
Load
L
N
PE

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

21/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

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 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. 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 100W (= 50% of the rated output load). From time to time a peak
power of 300W (= 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
150W
150W
120W

P0
100W
0W
50W

TPEAK
1s
1s
1s

T0
>25s
>1.3s
> 0.75s

PPEAK
150W
150W
150W

P0
50W
50W
50W

TPEAK
0.1s
1s
3s

T0
>0.16s
>1.6s>4.9s

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

22/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series23.2. PEAK CURRENT CAPABILITY
The DC/DC converter can deliver peak currents (up to several milliseconds) which are higher than the specified shortterm currents. This helps to start current demanding loads. Solenoids, contactors and pneumatic modules often have asteady state coil and a pick-up coil. The inrush current demand of the pick-up coil is several times higher than thesteady-state current and usually exceeds the nominal output current. The same situation applies when starting acapacitive load.
The peak current capability also ensures the safe operation of subsequent circuit breakers of load circuits. The loadbranches are often individually protected with circuit breakers or fuses. In case of a short or an overload in one branch
circuit, the fuse or circuit breaker need a certain amount of over-current to open in a timely manner. This avoids
voltage loss in adjacent circuits.
The extra current (peak current) is supplied by the built-in large sized output capacitors of the DC/DC converter. The
capacitors get discharged during such an event, which 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

OutputVoltage

20.5V

14.5V
21A

8.4A
OutputCurrent

0A
10ms/DIV

0A

8.4A Peak load (resistive) for 50ms
Output voltage dips from 24V to 20.5V.
Peak current voltage dips

typ.
typ.
typ.

from 24V to 20.5V
from 24V to 19.5V
from 24.5V to 14.5V

1ms/DIV

OutputCurrent

21A Peak load (resistive) for 5ms
Output voltage dips from 24V to 14.5V.
at 8.4A for 50ms, resistive load
at 21A for 2ms, resistive load
at 21A for 5ms, resistive load

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

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

23/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series23.4. EXTERNAL INPUT PROTECTION
The unit is tested and approved for branch circuits up to 30A (UL) and 32A (IEC). 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 6A B- or 3A C-Characteristic breaker should be used.

23.5. CHARGING OF BATTERIESThe DC/DC converter can be used to charge lead-acid or maintenance free batteries. (Two 12V batteries in series)
Instructions for charging batteries:a)b)

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

Use a 10A circuit breaker (or blocking diode) between the DC/DC converter and the battery.

c)Ensure that the output current of the DC/DC converter 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. 2.5mA when the power supply isswitched off (except in case a blocking diode is utilized).

23.6. PARALLEL USE TO INCREASE OUTPUT POWER
QS5.241-60 DC/DC converters can be paralleled to increase the output power. The output voltage shall be adjusted tothe same value (±100mV) with the same load conditions on all units, or the units can be left with the factory settings.
The ambient temperature is not allowed to exceed +60°C.
If more than three units are connected in parallel, a fuse or circuit breaker with a rating of 8A or 10A is required oneach output. Alternatively, a diode or redundancy module can also be utilized.

Fig. 23-5 Parallel use to increase the output power- Keep an installation clearance of 15mm (left / right)
between two DC/DC converters and avoid installing the
DC/DC converters on top of each other.

Unit A

Input+
Output+Unit B

Load

Input

+
OutputInstructions for parallel use:-

- Do not parallel DC/DC converters in orientations otherthan the standard mounting orientation (terminals onbottom of the unit) or in any other condition where aderating of the output current is required (e.g. altitude,
temperature, input voltages).
- Pay attention that EMI and inrush current will increase
when using multiple DC/DC converters.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

24/27

QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

23.7. PARALLEL USE FOR REDUNDANCY
QS5.241-60 DC/DC converters 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 DC/DC converter unit fails. The simplest way is
to put two DC/DC converters in parallel. This is called a 1+1 redundancy. In case one DC/DC converter unit fails, theother one is automatically able to support the load current without any interruption. Redundant systems for a higher
power demand are usually built in a N+1 method. E.g. five power supplies, each rated for 4.2A are paralleled to build
a 16.8A redundant system.
For N+1 redundancy the same restrictions apply as for increasing the output power, see also section 23.6.
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 a case, the defective unit becomes a load for the other power supplies
and the output voltage can not be maintained any more. This can be avoided by utilizing decoupling diodes which areincluded in the redundancy module YR2.DIODE.
Fig. 23-6 Redundant power design
FailureMonitor++ - -++ - -+- +-OutputIN 1 IN 2

Output

QS5.241-60
DC/DC-Conv.

YR2.DiodeQS5.241-60
DC/DC-Conv.

OUT+ - PE

Adj
DCok
OverloadINput+ - PE

Adj
DCok
Overload

Redundancy
ModuleINput+ -Recommendations for building redundant powersystems:- Use separate input fuses for each DC/DC converter.
- Monitor the individual DC/DC converter units.
Use the DC-OK relay contact of the QS5 DC/DC
converter.
- It is desirable to set the output voltages of all units
to the same value (± 100mV) or leave it at thefactory setting.

optional
I

I

24V
Load
L
N
PE

23.8. SERIES OPERATION
DC/DC converters 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 apotential above 60Vdc are not SELV any more and can be dangerous. Such voltages must be installed with a protection
against touching.
Avoid return voltage (e.g. from a decelerating motor or battery) which is applied to the output terminals.
Fig. 23-7 Parallel use to increase the output power
Unit A

Input

OutputOutput- Keep an installation clearance of 15mm (left / right)
between two DC/DC converters and avoid installing the
DC/DC converters on top of each other.

++

Unit B

Input

Load

+
-

Instructions for series use:-

- Do not use DC/DC converters in series in mounting
orientations other than the standard mounting orientation(terminals on bottom of the unit).
- Pay attention that EMI and inrush current will increase
when using multiple DC/DC converters.

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series

23.9. BACK-FEEDING LOADS
Loads such as decelerating motors and inductors can feed voltage back to the DC/DC converter. This feature is also
called return voltage immunity or resistance against Back- E.M.F. (Electro Magnetic Force).
This DC/DC converter is resistant and does not show malfunctioning when a load feeds back voltage to the DC/DC
converter. It does not matter whether the DC/DC converter is on or off.
The maximum allowed feed-back-voltage is 35Vdc.

23.10. USE IN A TIGHTLY SEALED ENCLOSURE
When the DC/DC converter is installed in a tightly sealed enclosure, the temperature inside the enclosure will behigher than outside. In such situations, the inside temperature defines the ambient temperature for the DC/DC
converter.
The following measurement results can be used as a reference to estimate the temperature rise inside the enclosure.
The DC/DC converter 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 9516 100, plastic, 110x180x165mm
24V, 3.2A; (=80%) load is placed outside the box
110Vdc
32.8°C (in the middle of the right side of the DC/DC converter with a distance of 2cm)
22.4°C
14.4K

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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QS5.241-60
24V, 100W, DC/DC CONVERTER

Q-Series23.11. MOUNTING ORIENTATIONSMounting orientations other than all terminals on the bottom require a reduction in continuous output power or alimitation in the maximum allowed ambient temperature. The amount of reduction influences the lifetime expectancyof the DC/DC converter. 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. 23-8
Mounting
Orientation A(Standardorientation)

Output Current

4A

OUTPUT

A1

4.2A

3

Power
Supply2
1
Ambient Temperature

0

INPUT

20
Fig. 23-9
Mounting
Orientation B(Upside down)

30

40

60

50

70°C

Output Current
4.2A

INPUT

4A

A1

3

A2

Power
Supply2
1
Ambient Temperature

OUTPUT

020

Fig. 23-10
Mounting
Orientation C(Table-top
mounting)

30

40

60

50

70°C

Output Current
4.2A

4A

A2
A1

3
2
1

Ambient Temperature

0
20

60

50

4.2A

4A

70°C

OUTPUT

Power
Supply

A2
A1

3
2
1

Ambient Temperature

0
20

30

40

60

50

70°C

Output Current
4.2A

A2
A1

3
INPUT

Power
Supply4A
OUTPUT

Fig. 23-12
Mounting
Orientation E(Horizontal ccw)

40

Output Current

INPUT

Fig. 23-11
Mounting
Orientation D(Horizontal cw)

30

2
1
Ambient Temperature

0
20

30

40

50

60

70°C

Aug. 2016 / Rev. 1.0 DS-QS5.241-60-EN
All parameters are specified at 24V, 4.2A, 110Vdc, 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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