QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

DC/DC CONVERTER
▪
▪
▪
▪
▪
▪
▪
▪
▪
▪
▪
▪

EN 50155 Railway Compliant
Conformal Coated PC-boards
Quick-connect Spring-clamp Terminals
77-154Vdc Wide-range Input
Width only 60mm
Efficiency up to 93.0%
Excellent Partial Load Efficiency
Minimal Inrush Current Surge
Full Power Between -40°C and +70°C
DC OK Relay Contact
Reverse Input Polarity Protected
3 Year Warranty

GENERAL DESCRIPTIONSHORT-FORM DATAThe QS10.241-60 DC/DC converter is designed specifically for
railway & transportation applications. It is approved according
to the EN 50155 standard, which is an international standard
covering electronic equipment used on rolling stock for railway
applications. The standard covers aspects such as temperature,humidity, shock, vibration, EMI and other parameters. Becauseof 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 remote monitoring,and quick-connect spring-clamp terminals for a reliable
connection even when mechanical vibration and shock are
involved. The unit also covers an extreme wide temperature
range from -40°C up to +70°C with full output current.
This DC/DC converter comes in a very compact housing andrequires only 60mm space on the DIN rail due to the highefficiency and low power losses. The high efficiency is achievedby utilizing cutting edge technology and other unique design
techniques.

ORDER NUMBERS

Output power
Output ripple
AC Input voltage
DC Input voltage
DC Input current
Inrush current
Efficiency
LossesTemperature range
Derating
Hold-up time
Dimensions
WeightDC 24V24 - 28V
8.3 – 7.1A
12.5 – 10.7A
200W
300W
max. 50mVpp
DC 110V
1.96A
typ. 4A peak
93.0%
15.0W
-40°C to +70°C
typ. 23ms
60x124x117mm
920g / 2.03lb

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

MAIN APPROVALS

DC/DC converter QS10.241-60
Accessory

ZM13.SIDE
YR2.DIODE
UF20.241

Side mount bracket
Redundancy module
Buffer module

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

1/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

INDEX
Page
1. Intended Use............................................................. 3
2. Installation Instructions ............................................. 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.................................................. 9
9. 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. Approved, Fulfilled or Tested Standards ................... 18

Page
20. Regulatory Product Compliance............................... 18
21. Physical Dimensions and Weight.............................. 19
22. Accessories ............................................................. 20
22.1. ZM13.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....................... 2323.4. 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 with standard 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.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

2/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

1. INTENDED USEThis device is designed for installation in an enclosure and is intended for use in rolling stock equipment for railway applications
according to EN 50155 or for use in industrial control, process control, monitoring and measurement equipment or the like.
Do not use this device in equipment, where malfunctioning may cause severe personal injury or threaten human life without additional
appropriate safety devices, that are suited for the application.
If this device is used in a manner outside of its specification, the protection provided by the device may be impaired.

2. INSTALLATION INSTRUCTIONS
Install device in an enclosure providing protection against electrical, mechanical and fire hazards.
Install the device onto a DIN-rail according to EN 60715 with the input terminals on the bottom of the device. Other mounting
orientations require a reduction in output current.
Make sure that the wiring is correct by following all local and national codes. Use appropriate copper cables that are designed for aminimum operating temperature of 60°C for ambient temperatures up to +45°C, 75°C for ambient temperatures up to +60°C and 90°C
for ambient temperatures up to +70°C. Ensure that all strands of a stranded wire enter the terminal connection.
The device is designed for pollution degree 2 areas in controlled environments. No condensation or frost allowed.
The enclosure of the device provides a degree of protection of IP20.
The device is designed as “Class of Protection” I equipment according to IEC 61140.
Do not use without a proper PE (Protective Earth) connection.
The device can be powered from a regulated power supply or a similar DC source. The voltage between the supply voltage terminals andground must not exceed 154Vdc.
A disconnecting means shall be provided for the input of the device.
The device is designed for convection cooling and does not require an external fan. Do not obstruct airflow and do not cover ventilation
grid!
The device is designed for altitudes up to 5000m. See additional requirements in the product datasheet for use above 2000m.
Keep the following minimum installation clearances: 40mm on top, 20mm on the bottom, 5mm left and right side. Increase the 5mm to15mm in case the adjacent device is a heat source. When the device is permanently loaded with less than 50%, the 5mm can be reduced
to zero.
The device is designed, tested and approved for branch circuits up to 20A without additional protection device. If an external fuse isutilized, do not use circuit breakers smaller than 6A B- or 4A C-Characteristic to avoid a nuisance tripping of the circuit breaker.
The maximum surrounding air temperature is +85°C. The operational temperature is the same as the ambient or surrounding air
temperature and is defined 2cm below the device.
The device is designed to operate in areas between 5% and 95% relative humidity.
Check for correct supply voltage polarity. The device will not operate when the voltage is reversed.

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 block for 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.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

3/27

QS10.241-60
24V, 200W, 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 not recommended and cancause a malfunction or damage the unit.
Input voltage
Input voltage range

nom.

Input current
Allowed voltage between input toearth (ground)
Allowed input ripple voltage

typ.
max.

Turn-on voltage

typ.

max.

DC 110V
77-154Vdc
66-77Vdc
1.96A
375Vdc-30%/+40%

15Vpp
3Vpp
71Vdc

50Hz –10kHz
10kHz – 50kHz
steady-state value, at ambient temperatures between-40°C and +70°C, see Fig. 4-1
steady-state value, see Fig. 4-1
see Fig. 4-2
at 8.3A constant current load, 0mF load capacitance, see Fig.
4-2
at 8.3A constant current load, 8mF load capacitance, see Fig.
4-2
see Fig. 4-2

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

X

Shut-down voltage
Start-up delay
Rise time

typ.
typ.
typ.

61Vdc
500ms
20ms

X

X

X

X

X

X

X

X

typ.

45ms

X

X

Turn-on overshoot

max.

200mV

External input protection

See recommendations in chapter 23.4 .
X

Rated
input range

max.
500ms

Turn-onShut -dow n

X

Fig. 4-2 Turn-on behavior, definitions

Input
Voltage

OutputVoltage

VIN
77V

X

154V

- 5%
Start-up Rise
delay
Time

OvershootFig. 4-1 Input voltage range

POUT

X

375VdcMar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

4/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

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

2A
1.5
1.0
0.5
0

0

1

2

3

4

5

6

7

8 9A

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
Inrush delay

max.
typ.
max.
typ.

13Apeak
4Apeak1A2s
500ms

at 110Vdc, temperature independent
at 110Vdc, temperature independent
at 110Vdc, temperature independent
start-up delay plus rise time at 110Vdc

Fig. 5-1 Typical input inrush current behaviour at nominal load and 25°C
ambient

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

5/27

QS10.241-60
24V, 200W, 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
10mV
100mV
50mVpp
8.3A
7.1A
12.5A *)

nom.

10.7A *)

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

200W
300W *)
4s
3s
5s
7s
cont. current
6.7A **)
10.5A **)
17.5A **)
22.5A **)
12.5A **)
7 000µF

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 → 8.3A
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
X

X

X

X

X

X

X

X

X

X

overload free time to reset power manager, see Fig. 6-3
XX

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
X

X

X

X

X

X

BonusPower, short term power capability (up to typ. 4s)
The power supply is designed to support loads with a higher short-term power requirement without damage or shutdown. The short-term duration is
hardware controlled by an output power manager. This BonusPower is repeatedly available. Detailed information can be found in chapter 23.1 . If thepower supply is loaded longer with the BonusPower than shown in the Bonus-time diagram (see Fig. 6-2 ), the max. output power is automatically reduced
to 200W.
Discharge current of output capacitors is not included.
X

X

**)
***)

X

X

This is the maximum output voltage which can occur at the clockwise end position of the potentiometer due to tolerances. It is not a guaranteed value,
which can be achieved. The typical value is about 28.6V.

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

Fig. 6-2 Bonus time vs. output power

Adjustment
Range

Output Voltage

28V

Bonus Time

24
sh o

12
8
4
0

er m

16

r t -tco nt in uo us

20

Output Current

0

4

8

12

16

20A

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

m ax
typ

m in
Output Power

120

130

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

140

150

160%

6/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

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

Power
Demand
100%

t
Bonus
Time

OutputVoltage

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

Fig. 6-5 BonusPower after output short

Short ofOutput

Input
Voltage

OutputVoltage

OutputVoltage150%
Output
Power

100%

Bonus
Power

Output
Power

150%

Bonus
Power

100%

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

7/27

QS10.241-60
24V, 200W, 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.

47ms
36ms
23ms
18ms

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

at 4.15A, see Fig. 7-1
at 4.15A, see Fig. 7-1
at 8.3A, see Fig. 7-1
at 8.3A, see Fig. 7-1
X

X

X

X

X

X

X

X

Fig. 7-2 Shut-down behavior, definitions

Hold-up Time

50ms

at 4.15A, typ.

40

at 4.14A, min.

30

Input
Voltage

at 8.3A, typ.

20
at 8.3A, min.

10

- 5%

OutputVoltage
Hold-up Time

0
70

90

110

130

150VdcInput Voltage

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

8/27

QS10.241-60
24V, 200W, 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 back-fed voltage from aunit 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

X

X

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 be on and the DC OK contact will be open. The
overload signal will only shut off as soon as the adjusted voltage is reached. This is an
important condition to consider particularly, if the load is a battery, the power
supply is used in parallel or the power supply is used for N+1 redundant systems.

closedMar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

9/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

9. EFFICIENCY AND POWER LOSSES
Efficiency
Average efficiency*)

typ.
typ.

93.0%
92.1%

Power losses

typ.
typ.
typ.

4.3W
7.8W
15.0W

*)

at 110Vdc input and 24V, 8.3A
25% at 2.1A, 25% at 4.2A,
25% at 6.2A. 25% at 8.3A
at 110Vdc input and 24V, 0A
at 110Vdc input and 24V, 4.2A (= 50% load)
at 110Vdc input and 24V, 8.3A

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 nom inal load for the rest of thetime.

Fig. 9-1 Efficiency vs. output current, at 24V, typ.

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

Efficiency

Power Losses

94%
93
92
91
90
89
88
87
86

16W
14
12
10
8
6
4
2
0

Output Current

1

2

3

4

5

6

7

8

9A

Output Current

0

1

2

3

4

5

6

7

8 9A

10. LIFETIME EXPECTANCY AND MTBF
Lifetime expectancy*)

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

140 000h*)
325 000h*)
94 000h*)
266 000h*)
688 000h
1 181 000h
333 000h
450 000h
75 000h
100 000h

at 24V, 4.2A and 40°C
at 24V, 4.2A and 25°C
at 24V, 8.3A and 40°C
at 24V, 8.3A and 25°C
at 24V, 8.3A and 40°C
at 24V, 8.3A and 25°C
at 24V, 8.3A and 40°C, Ground Benign GB40
at 24V, 8.3A and 25°C, Ground Benign GB25
at 24V, 8.3A and 40°C, Ground Fixed GF40
at 24V, 8.3A 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 the capacitor’s manufacturer specification. The
manufacturer of the electrolytic capacitors only guarantees a maximum life of up to 15 years (131 400h). Any number exceeding this value is a calculated
theoretical lifetime which can be used to compare devices.
**) MTBF stands for Mean Time Between Failure, which is calculated according to statistical device failures, and indicates reliability of a device. It is the statisticalrepresentation of the likelihood of a unit to fail and does not necessarily represent the life of a product.
The MTBF figure is a statistical representation of the likelihood of a device to fail. A MTBF figure of e.g. 1 000 000h means that statistically one unit will failevery 100 hours if 10 000 units are installed in the field. However, it can not be determined if the failed unit has been running for 50 000h or only for 100h.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

10/27

QS10.241-60
24V, 200W, 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

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

DC-okcontact

11/27

QS10.241-60
24V, 200W, 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.
Type
Solid wire
Stranded wire
American Wire Gauge
Max. wire diameter
Wire stripping length
Screwdriver
Recommended tightening torque

Input and output
Bi-stable, quick-connect spring-clamp
terminals
max. 6mm2
max. 4mm2
AWG20-10
2.8mm (including ferrules)
10mm / 0.4inch
not required
not applicable

DC OK-Signal
Bi-stable, quick-connect spring-clamp
terminals
max. 6mm2
max. 4mm2
AWG20-10
2.8mm (including ferrules)
10mm / 0.4inch
not required
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.
e) Ferrules are allowed.

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 25A. If the current is higher, use a separate distribution terminal block as shown in Fig. 12-3 .
X

Fig. 12-2 Daisy chaining of outputs

X

Fig. 12-3 Using distribution terminals

max 25A!

OutputOutput

+ + -

+ + -

-

-

+

-

Load

OutputOutput

+ + -

+ + -

-

-

DC/DC
Converter

DC/DC
Converter

DC/DC
Converter

DC/DC
Converter

Input

Input

Input

Input

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

+

-

Load

Distribution
Terminals

12/27

QS10.241-60
24V, 200W, 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 per pole)+
Positive output–
Negative (return) output

C

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

X

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, orin case of a short circuit in the output. Input voltage is required
Flashing, when the unit has switched off due to overtemperature.

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

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

DC OK Contact
ClosedClosed
Open
Open
Open
Open

13/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

14. EMCThe DC/DC converter is suitable for rolling stock railway applications, for applications in industrial environment as well as in residentialcommercial and light industry environment without any restrictions.
EMC Immunity
Electrostatic discharge
Electromagnetic RF field
Fast transients (Burst)

Surge voltage on input
Surge voltage on output
Surge voltage on DC OK
Conducted disturbancePower – Frequency magnetic
fieldPower – Frequency magnetic
field
Pulsed magnetic field

According generic standards: EN 61000-6-1 and EN 61000-6-2 andaccording to EN 50121-3-2
EN 61000-4-2
contact discharge
8kV
air discharge
15kV
EN 61000-4-3
80MHz-2.7GHz
20V/m
EN 61000-4-4
input lines
4kV
output lines
2kV
DC OK signal (coupling clamp)
2kV
EN 61000-4-5+→2kV+ → PE, - → PE
4kV+→0.5kV
EN 61000-4-5+ / - → PE
1kV
EN 61000-4-5
DC OK signal → PE
1kV
EN 61000-4-6
0.15-80MHz
10V
EN 61000-4-8
16.7Hz, 50Hz
100A/mCriterion 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

EN 61000-4-8

300A/mCriterion A

300A/mCriterion B

0Hz

EN 61000-4-9

Criterions:
A: DC/DC converter shows normal operation behavior within the defined limits.
B: During the test the output voltage can slightly drift below or above the specified limits.

EMC Emission
Conducted emission
input lines
Conducted emission
output lines

According generic standards: EN 61000-6-3 and EN 61000-6-4
and according to EN 50121-3-2
CISPR 16-1-2, CISPR 16-2-1

CISPR 16-1-2, CISPR 16-2-1

limits for EN 50121-3-2 fulfilled,
limits for DC power port according
EN 61000-6-3 fulfilledlimits for EN 50121-3-2 fulfilled,
limits for DC power port according
EN 61000-6-3 fulfilled
Class B

Radiated emission
EN 55011, EN 55022, EN 50121-3-2This device complies with FCC Part 15 rules.
Operation is subjected to following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.

Switching Frequencies
Switching frequency 1
Switching frequency 2
Switching frequency 3

The power supply has three converters with three different switching frequencies included. Two arenearly constant. The other one is input voltage and load dependent.
35kHz
nearly constant
105kHznearly constant
40kHz to 220kHz
input voltage and load dependentMar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

14/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

15. ENVIRONMENT
Conformal coating
Operational temperature*)Vibration broadband

yes-40°C to +70°C (-40°F to 158°F)+70°C to +85°C (158°F to 185°F)-40 to +85°C (-40°F to 185°F)
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 5000m (6 560 to 20 000ft)

Storage temperature
Humidity **)Vibration sinusoidal

Shock

all pc-boards are conformal coatedcontinuous operation
for maximal 10 minutes every hourfor storage and transportation
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
12W/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 5000m
2
IEC 62103, EN 50178, not conductive
The unit does not release any silicone or other LABS-critical substances and is suitable for use in paintshops.

AltitudeX

Altitude de-rating
Overvoltage category

X

X

Degree of pollution
LABS compatibility

X*)
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
Al lowed Output Current
12.5A

12A

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

12A

10
8

12.5A for typ. 4s

10

8.3A

8.3A continuou s operation

8

6

6

4

4

2

2

0
-40

-20

0

20

40

60 70

85°C

Ambient Temperature

0
0

2000m

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

4000m 5000m
Al titude

15/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

16. PROTECTION FEATURES
Output protection
Output overvoltage protection

Degree of protection
Penetration protection
Overtemperature protection
Input transient protection
Internal input fuse
Reverse input polarity protection*)

Electronically protected against overload, no-load and short-circuits*)
typ. 35Vdc
In case of an internal DC/DC converter defect, a redundantmax. 39Vdc
circuit limits the maximum output voltage. The output shuts
down and automatically attempts to restart.
IP 20
EN/IEC 60529> 3.5mme.g. screws, small partsyes
Output shut-down with automatic restart
MOV (Metal Oxide Varistor)
DC suitable fuse included
not user replaceable
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 voltageI
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.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

16/27

QS10.241-60
24V, 200W, 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 the voltage with a slow ramp (2s up and 2sdown). Connect all input-terminals together as well as all output poles before conducting the test. When testing, set the cut-off current
settings to the value in the table below.
Type test

60s

A
2500Vac

B
3000Vac

C
500VacD
500VacFactory test

5s

2500Vac

2500Vac

500Vac

500VacField test

5s

2000Vac

2000Vac

500Vac

500VacCut-off current setting> 10mA> 10mA> 20mA> 1mA

Fig. 18-1 Dielectric strength

Input

DC-ok
B* )

+

B

A

D
OutputEarth, PEC+-

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

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

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

17/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

19. APPROVED, FULFILLED OR TESTED STANDARDSIEC 61010-2-201

CB Scheme Certificate
Electrical Equipment for Measurement, Control and Laboratory Use Particular requirements for control equipment
The manufacturer’s declaration indicate conformance with thefollowing characteristics:- Altitude category: AX (EN 50125-1 § 4.2.1)- Environmental category: TX (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)
Manufacturer's Declaration (Online Document)
Environmental Tests, Flowing Mixed Gas Corrosion Test
IEC 60068-2-60 Method 4
Test Ke - Method 4
H2S: 10ppb
NO2: 200ppb
Cl2: 10ppb
SO2: 200ppb
Test Duration: 3 weeks, this simulates a service life of 10 years.
Manufacturer's Declaration (Online Document)
Airborne Contaminants Corrosion Test
ISA-71.04 G3
Severity Level: G3 Harsh
H2S: 100ppb
NOx: 1250ppb
Cl2: 20ppb
SO2: 300ppb
Test Duration: 3 weeks, this simulates a service life of 10 years.

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

IEC 60068-2-60

ISA-71.04 G3

20. REGULATORY PRODUCT COMPLIANCEEC Declaration of Conformity

REACH Regulation (EU)

WEEE Regulation

The CE mark indicates conformance with the- EMC directive- Low-voltage directive- RoHS directive
Manufacturer's Statement
EU regulation regarding the Registration, Evaluation, Authorisation andRestriction of Chemicals (REACH) fulfilled.
Manufacturer's Declaration
EU Regulation on Waste Electrical and Electronic Equipment
Registered as business to business (B2B) products.
EU Regulation 2012/19/EU

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

18/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

21. PHYSICAL DIMENSIONS AND WEIGHT
Width
HeightDepth
WeightDIN Rail
Housing material
Installation clearances

60mm 2.36’’124mm 4.88’’
117mm 4.61’’
The DIN rail depth must be added to the unit depth to calculate the total required installation depth.
920g / 2.03lb
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 view

X

X

Fig. 21-2 Side view

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

19/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

22. ACCESSORIES

22.1. ZM13.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 theblack 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 thehold-up time after turn-off of the input power. In
Power
Buffertimes when the power supply provides sufficient
Load
AC
SupplyUnit(s)voltages, the buffer unit stores energy in+integrated electrolytic capacitors. In case of input
DC
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 to the load circuit
at any given point. Buffer units can be added in parallel to increase the output ampacity or the
hold-up time.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

20/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series22.3. YR2.DIODE REDUNDANCY MODULEThe YR2.DIODE is a dual redundancy module, which has two diodes as
decoupling devices included. It can beused for various purposes. The mostpopular application is to configure 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 cancause controller failures.

FailureMonitor++ - -+- +-++ - -

OutputIN 1 IN 2

Output

QS10.241-60
DC/DC-Conv.

YR2.Diode

QS10.241-60
DC/DC-Conv.

OUT+ - PE

Adj
DCok
Overload

Redundancy
ModuleInput+ - PE

Adj
DCok
Overload

Input

+ -

optional
I

I

24V
Load
L
N
PE

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

21/27

QS10.241-60
24V, 200W, 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 a higher short-term
power demand (=BonusPower). The short-term duration is hardware controlled by an output power manager and is available on arepeated basis. If the BonusPower load lasts longer than the hardware controller allows it, the output voltage will dip and the next
BonusPower is available after the BonusPower recovery time (see chapter 6 ) has elapsed.
XX

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 the maximum duty cycle
curve ( Fig. 23-2 ) to check if the average output current is below the nominal current.
X

X

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 themax. duty cycle from the duty cycle-axis (= 0.37)- Calculate the required pause (base load) length T 0:
- Result: The required pause length = 1.7s

T0=

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

DutyCycle=

1s- (0.37 x 1s)
0.37

=1.7s

More examples for pulse load compatibility:
PPEAK
300W
300W
250W

P0
200W
0W
100W

TPEAK
1s
1s
1s

T0
>25s
>1.3s
> 0.75s

PPEAK
300W
300W
300W

P0
100W
100W
100W

TPEAK
0.1s
1s
3s

T0
>0.16s
>1.6s>4.9s

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

22/27

QS10.241-60
24V, 200W, 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 short term currents. This
helps to start current demanding loads. 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. The same situation applies when starting a capacitive load.
The peak current capability also ensures the safe operation of subsequent circuit breakers of load circuits. The load branches 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 breakerneed a certain amount of overcurrent 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.

OutputVoltage

24V

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

24V
OutputVoltage

22.5V
14.5V
41.5A

16.6A
OutputCurrent

0A

0A

10ms/DIV

16.6A Peak load (resistive) for 50ms
Output voltage dips from 24V to 22.5V.
Peak current voltage dips

typ.
typ.
typ.

1ms/DIV

OutputCurrent

41.5A Peak load (resistive) for 5ms
Output voltage dips from 24V to 14.5V.
from 24V to 22.5V
from 24V to 19V
from 24.5V to 14.5V

at 16.6A for 50ms, resistive load
at 41.5A for 2ms, resistive load
at 41.5A 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.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

23/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series23.4. EXTERNAL INPUT PROTECTION
The unit is tested and approved for branch circuits up to 20A. An external protection is only required if the supplying branch has anampacity greater than this. Check also local codes and local requirements. In some countries local regulations might apply.
If an external fuse is necessary or utilized, minimum requirements need to be considered to avoid nuisance tripping of the circuit
breaker. A minimum value of 6A B- or 4A 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)

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 15A or 16A 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. 3mA when the power supply is switched off (except incase a blocking diode is utilized).

23.6. PARALLEL USE TO INCREASE OUTPUT POWER
QS10.241-60 DC/DC converters 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. The ambient temperature is notallowed to exceed +60°C.
If more than three units are connected in parallel, a fuse or circuit breaker with a rating of 15A or 16A is required on each output.
Alternatively, a diode or redundancy module can also be utilized.

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

Input

+
Output+Unit B

Load

Input

+
OutputInstructions for parallel use:-

- Do not parallel DC/DC converters in orientations other than thestandard mounting orientation (input terminals on bottom of theunit) or in any other condition where a derating 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.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

24/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series

23.7. PARALLEL USE FOR REDUNDANCY
QS10.241-60 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 inparallel. This is called a 1+1 redundancy. In case one DC/DC converter unit fails, the other one is automatically able to support the load
current without any interruption. Redundant systems for a higher power demand are usually built in a N+1 method. E.g. five power
supplies, each rated for 8.3A are paralleled to build a 33.2A redundant system.
For N+1 redundancy the same restrictions apply as for increasing the output power, see also section 23.6 .
X

X

Please note: This simple way to build a redundant system does not cover failures such as an internal short circuit in the secondary sideof 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 are included in the redundancy module YR2.DIODE.
Fig. 23-6 Redundant power design
FailureMonitor++ - -++ - -+- +-OutputIN 1 IN 2

Output

QS10.241-60
DC/DC-Conv.

YR2.Diode

QS10.241-60
DC/DC-Conv.

OUT+ - PE

Adj
DCok
Overload

Redundancy
ModuleInput+ - PE

Adj
DCok
Overload

Recommendations for building redundant power systems:- Use separate input fuses for each DC/DC converter.
- Monitor the individual DC/DC converter units.
Use the DC OK relay contact of the QS10 DC/DC converter.
- It is desirable to set the output voltages of all units to thesame value (± 100mV) or leave it at the factory setting.

Input

+ -

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 inseries 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.
Avoid return voltage (e.g. from a decelerating motor or battery) which is applied to the output terminals.
Fig. 23-7 Wiring scheme for series operation
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 topof 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 (input terminals onbottom of the unit).
- Pay attention that EMI and inrush current will increase when using
multiple DC/DC converters.

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

25/27

QS10.241-60
24V, 200W, 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 notmatter whether the DC/DC converter is on or off.
The maximum allowed feed-back-voltage is 35Vdc. The absorbing energy can be calculated according to the built-in large sized output
capacitor which is specified in chapter 6.

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 be higher 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 9519 100, plastic, 180x180x165mm
24V, 6.6A; (=80%) load is placed outside the box
110Vdc
38.9°C (in the middle of the right side of the DC/DC converter with a distance of 2cm)
22.1°C
16.8K

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

26/27

QS10.241-60
24V, 200W, DC/DC CONVERTER

Q-Series23.11. MOUNTING ORIENTATIONSMounting orientations other than all terminals on the bottom require a reduction in continuous output power or a limitation in the
maximum allowed ambient temperature. The amount of reduction influences the lifetime expectancy of the DC/DC converter.
Therefore, two different derating curves for continuous operation can be found below:
Curve A1 Recommended output current.
Curve A2 Max allowed output current (results in approximately half the lifetime expectancy of A1).
Fig. 23-8
Mounting
Orientation A(Standardorientation)

Output Current

8A

OUTPUT

A1

8.3A

6

DC/DC
Converter

4
2
Ambient Temperature

0

INPUT

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

30

40

50

60

70°C

Output Current
8.3A

INPUT

8A

A2
A1

6

DC/DC
Convert er

4
2
Ambient Temperature

OUTPUT

020

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

30

40

50

60

70°C

Output Current
8.3A

8A

A2
A1

6
4
2

Ambient Temperature

0
20

50

60

70°C

8.3A

8A
OUTPUT

DC/DC
Convert er

A2
A1

6
4
2

Ambient Temperature

0
20

30

40

50

60

70°C

Output Current
8.3A

A2

6
INPUT

DC/DC
Convert er

8A
OUTPUT

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

40

Output Current

INPUT

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

30

A1

4
2
Ambient Temperature

0
20

30

40

50

60

70°C

Mar. 2024 / Rev. 1.1 DS-QS10.241-60-EN
All parameters are specified at 24V, 8.3A, 110Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

27/27