UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

BUFFER MODULE
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Buffering with electrolytic capacitors instead of leadacid batteries
Buffering of 48V loads
Minimum hold-up time 0.1s at 20A, 0.2s at 10A andlonger hold-up time at lower loads
Clear status indication by status LED and signaling
terminals
Quick-connect spring-clamp terminals
3 Years warranty

GENERAL DESCRIPTIONSHORT-FORM DATAThe UF20 buffer module is a supplementary device forregulated DC 48V power supplies, which can be used forvarious purposes:- Deliver DC-power to bridge failures of the DC
voltage supply system.
- Extend the hold-up time after loss of the AC power.
- Deliver extra short-term peak current above thecurrent rating of the power supply.

Supply voltage
Required voltage tocharge capacitors
Threshold voltage
for buffer mode
Buffer voltage
Buffer current
Charging time
Current consumption

It utilizes service-free electrolytic capacitors for storing
the energy which allows usage even at ambient
temperatures up to +70°C.
The buffer module does not require any control wiring.
It can be added in parallel to the load circuit at any
given point.

Power dissipation
Buffer time

Buffer modules can be connected in parallel to increase
the output ampacity or the hold-up time.
Temperature range
Dimensions
WeightORDER NUMBERS

DC 48V -20%/+25% 38.4-60Vdc
46Vdc
45V / VIN-2V

Selectable

45V / VIN-2V
20A
Typ. 21s
Typ. 40mA
Max. 500mA
1.9W
Min. 100ms
Min. 200ms
Typ. 150ms
Typ. 300ms
Typ. 21s-25°C to +70°C
64x124x102mm
740g / 1.63lb

Selectable

Stand-by mode
During charging
Stand-by mode
At 45V, 20A
At 45V, 10A
At 45V, 20A
At 45V, 10A
At 45V, 0.1A
Operational
WxHxD

MARKINGS

Buffer Module UF20.481
Accessory

ZM1.WALL
ZM14.SIDE

Panel/ wall-mount bracket
Side-mount bracket

IND. CONT. EQ.

UL 508

UL 60950-1

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

EMC

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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

INDEX
Page
1. Intended Use .......................................................3
2. Installation Notes ................................................3
3. Functional Description ........................................4
4. Electrical Ratings .................................................5
5. Selection of the Back-up Threshold Voltage .....6
6. Buffer Time..........................................................6
7. Charging Time .....................................................7
8. Operating Diagrams............................................7
9. Active Signal ........................................................8
10. Ready Signal ........................................................8
11. Inhibit Input.........................................................8
12. Efficiency and Power Losses................................913. Lifetime Expectancy and MTBF...........................9
14. Functional Diagram...........................................10Page
15. Terminals and Wiring....................................... 10
16. Front Side and User Elements .......................... 11
17. EMC ................................................................... 12
18. Environment ..................................................... 13
19. Protection Features .......................................... 13
20. Safety Features ................................................. 13
21. Dielectric Strength............................................ 14
22. Approvals .......................................................... 14
23. Physical Dimensions and Weight ..................... 15
24. Accessories ........................................................ 16
24.1. ZM1.WALL - Wall mounting bracket .......1624.2. ZM14.SIDE - Side Mounting Bracket........17
25. Wiring Diagrams............................................... 18

The information given in this document is correct to the best of our knowledge and experience at the time of publication. If not
expressly agreed otherwise, this information does not represent a warranty in the legal sense of the word. As the state of ourknowledge and experience is constantly changing, the information in this data sheet is subject to revision. We therefore kindly ask
you to always use the latest issue of this document (available under www.pulspower.com). No part of this document may be
reproduced or utilized in any form without our prior permission in writing.
Some parts of this unit are patent by PULS (US patent No 091662,063, Des. 424,529, …).

TERMINOLOGY AND ABREVIATIONSPower supply mode

Describes a condition where the supply voltage is in the rated supply voltage range and the
supplying power supply can deliver a sufficient amount of current for the buffer module andthe load. The mode can also be called “Normal mode”.

Buffer mode

Describes a condition where the input voltage is below the transfer threshold level, the unit
is running on capacitors (buffering) and the output is loaded within the allowed limits.
The mode can also be called “Capacitor mode”.

Inhibit mode

Describes a condition where buffering is disabled on purpose (e.g. for service actions).

T.b.d.

To be defined, value or description will follow later.

DC 48VA figure displayed with the AC or DC before the value represents a nominal voltage withstandard tolerances included.
E.g.: DC 12V describes a 12V battery disregarding whether it is full (13.7V) or flat (10V).

48Vdc

A 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.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
UF-Series

48V, 20A, 100MS, BUFFER MODULE

1. INTENDED USEThis device is designed for installation in an enclosure. Use an appropriate enclosure which protects against
mechanical, electrical and fire hazards.
This device is intended for professional use in areas such as in industrial control, office, communication, andinstrumentation equipment.
Do not use this device in equipment or systems where malfunction may cause severe personal injury or threaten
human life.

2. INSTALLATION NOTESThis device may only be installed and put into operation by qualified personnel.
This device does not contain serviceable parts or fuses.
If damage or malfunction should occur during installation or operation, immediately turn power off and send unit to
the factory for inspection.
The unit must be powered from a SELV source (according to IEC 60950-1), PELV source (according to IEC 62477-1) or an
Isolated Secondary Circuit (according to UL 508) power source.
Use DIN-rails according to EN 60715 with a height of 7.5 or 15mm.
Mounting orientation must be power terminals on top of the unit.
Do not obstruct air flow as the unit is convection cooled. Ventilation grid must be kept free of any obstructions.
Signal lines (ready, active and inhibit) must be shorter than 30m.
Use an appropriately sized power supply, which can deliver the additional required internal current consumption(including the charging current) specified as input current in the table of chapter 4 and Fig. 4-1.
The following installation clearances must be maintained:- Left / right: 0mm- On top of the unit: 40mm
- On bottom of the unit: 20mm
Agency approvals apply only for altitudes up to 2000m.
Maximum surrounding air temperature: +70°C / +158°F.
Caution for Canada: For use in a controlled environment according to CSA 22.2 No 107.1-01.

WARNING

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

- 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 dangerous voltages may be 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.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

3. FUNCTIONAL DESCRIPTION
Working principle
When the power supply provides sufficient voltage, the buffer module stores energy inthe integrated electrolytic capacitors. In case of a voltage dip or loss, this energy isreleased to the DC bus in a regulated process.
Bridges mains faults without interruption
Statistic show that 80% of all mains fault lasts less than 0.2s. These mains faults arecompletely bridged by the buffer unit up to 10A load current. For higher load currents
use multiple buffer modules in parallel. This increases the reliability of the system as awhole.
Extended hold-up time
Once mains power fails or is switched off, the buffer unit will continue to provide theload current for a defined period of time. Process data can be saved and processes can beterminated before the DC power switches off. Controlled restarts are subsequently
possible.
Easy to handle, expandable and maintenance-free
The buffer module does not require any control wiring. It can be added parallel to theload circuit at any given point. Buffer modules can be connected in parallel to increase
the output ampacity or the hold-up time.

Fig. 3-1 Typical wiring diagram

Load

-

-

optional+

BufferModule
+

L PE

+

N

Storage

Discharge

AC
DC
Buffer Module

AC
DC
Buffer Module

Power
SupplyAC

BufferModule

Load

+
-

DC

Fig. 3-2 Transfer behavior
Power
SupplyOutputPower
SupplyChargeDC

Transfer ThresholdtSupplyVoltage
Power
SupplyMode

BufferMode

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0GermanyPower
SupplyMode t4/18

UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

4. ELECTRICAL RATINGS
DC 48V -20%/+25%
38.4 - 60Vdc
46 – 60Vdc
45Vdc
VIN – 2V

Supply voltage
Supply voltage range1)
Normal operating voltage range2)
Transfer voltage for switching
into buffer mode

Nom.
Nom.
Typ.
Typ.
Typ.

Transfer voltage for switchingfrom buffer mode into power
supply mode

Typ.
Typ.

Buffer voltage
Ripple and noise voltage- in buffer mode

Typ.

Back-up threshold jumper set to “45V fixed”
Back-up threshold jumper set to “VIN – 2V”
See also chapter 5.
Back-up threshold jumper set to “45V fixed”
45Vdc
Back-up threshold jumper set to “VIN – 2V”
VBUFFER + 2V
See also chapter 5.
Same as the transfer voltage for switching into buffer mode.

Max.
Max.
Max.

250mVpp
400mVpp
600mVpp- in power supply mode
Current consumption

Power dissipation
Buffer current
Buffer current overload behavior
Allowed voltage between supply
voltage and chassis ground
Capacitive and inductive loads

Typ.
Min.
Max.
Typ.
Min.

Max.

At 5A generated by the buffer module
At 10A generated by the buffer module
At 20A generated by the buffer module
Defined at 20Hz to 20MHz, 50Ohm
The ripple and noise voltage is defined by the power supply.
40mA
When capacitor is fully charged
300mA
During charging of the capacitors
500mA
During charging of the capacitors
1.9W
When capacitor is fully charged
20A
Electronically limited, buffering stops and capacitor gets discharged
below 34V. See Fig. 4-2.
60Vdc orContinuous, IEC 62477-1
42.4Vac
No limitation

1) Supply Voltage Range:
At voltages within the input voltage range, control functions such as LEDs, monitoring features, relay contacts, etc. are functioning
normally. Within the input voltage range the unit can either be in power supply mode or in buffer mode.
2) Normal Operating Voltage Range:
The normal operating voltage range describes the supply voltage, which supports the full functionality of the buffer module (including
charging) but without entering the buffer mode.

Fig. 4-1 Selection of an appropriate power supply

Fig. 4-2 Output characteristic in buffer mode,
45V fixed mode, typ.
Buffer Voltage

56V
Power
SupplyCurrent

Load
Current

48

45V

40
32
24

Internal
current
consumption

Current
consumption
for charging

Buffering stops
below 34V

16
80

Output Current

0

4

8

12

16

20

24

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

28 32A

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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

5. SELECTION OF THE BACK-UP THRESHOLD VOLTAGE
The buffer behavior can be selected with the back-up jumper selector between “Fixed Mode” and “Variable Mode”.
Fixed Mode: (Jumper in position „2-3“ or „45V fixed”)
If the supply output voltage falls below 45V, buffering starts and the supply voltage will be kept at this level.
This adjustment is recommended:- when power supplies other than the DIMENSION Q-series are used
- with back-feeding loads- when the buffer module is placed close to the load or- whenever in doubt.
Variable Mode: (Jumper in position „1-2“ or „VIN – 2V”)
Buffering starts if the supply voltage decreases by more than 2V. Buffering ends when supply voltage increases bymore than 2V
Voltage changes slower than 1.1V/s will be ignored if the voltage is above 45V. Below 45V buffering starts
immediately.
This adjustment is recommended for any application where 45V is too low for the application or when the buffer
module is placed close to the power supply.
The factory setting is fixed mode, A missing jumper means also fixed mode.

6. BUFFER TIME
The buffer time (sometimes also called autonomy time) is the maximum period of time for which the capacitor canmaintain the required output current. The buffer time mainly depends on the output current in buffer mode.
To increase the buffer time any given number of buffer modules can be connected in parallel.
Buffer time

Min.
Min.
Typ.
Typ.
Typ.

100ms
200ms
150ms
300ms
21s

Fig. 6-1 Buffer time, typ.
Buffer Current, typ.

At 45V, 20A
At 45V, 10A
At 45V, 20A
At 45V, 10A
At 45V, 0.1A
Fig. 6-2 Buffer time for small buffer currents,
typ.
Buffer Current, typ.

20A

1.0A

15

0.75

10

0.5

5

0.25

0
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.4 3s
Buffer Time

0
3

6

9

12

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0

15

18s

Buffer Time

Germany

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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

7. CHARGING TIME
Charging of the internal capacitors is indicated by the status LED, which is flashing with a slow frequency (1.25Hz).
Charging time

Min.
Max.
Min.
Max.

Initial charging 1)
Initial charging 1)
Re-charging 2)
Re-charging 2)

22s
32s
17s
25s

1) Initial charging is the first charge after voltage is applied to the buffer module.
2) Re-charging is the charging of the internal capacitors after voltage interruptions shorter than 2minutes.

Fig. 7-1 Charging time, re-charging
Charge

min.

100%

max.

80
60
40
Charging Time

20
0

5

10

15

20

25

30s

8. OPERATING DIAGRAMS
Fig. 8-1 Operating diagram
V MainsFig. 8-2 Signal schematic
Hold-up Time Power Supplyt

V Buffer
Capacitor

6 +t

7 Active

Vout

Ready

Optocoupler high ohmic

ActiveOptocoupler high ohmictOptocoupler
low ohmic

8 Readyt

5,1V

Optocoupler low ohmic
LED

1.25Hz

10Hz

t

3mA

UF20

9 InhibittCharging Mode

StandbyMode

Buffer Mode

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

9. ACTIVE SIGNALThe signal “Active” (pin 7) is an opto-coupler output which is low ohmic while buffer capacitors are discharged.
Wiring scheme see Fig. 8-2, Fig. 25-1 and Fig. 25-2.
Signal voltage
Signal current
Voltage drop across opto-coupler
Leakage current
Isolation voltage

Max.
Max.

60Vdc
6mA
1.2V / 3.3V
Max.
50μA
See chapter 21.

Voltage between pin 6 and 7
At 1mA / 5mA while opto-coupler is low ohmic
While opto-coupler is high ohmic

10. READY SIGNALThe signal “Ready” (pin 8) is an opto-coupler output which is low ohmic when buffer capacitors are fully charged.
Wiring scheme see Fig. 8-2, Fig. 25-1 and Fig. 25-2.
Signal voltage
Signal current
Voltage drop across opto-coupler
Leakage current
Isolation voltage

Max.
Max.

60Vdc
6mA
1.2V / 3.3V
Max.
50μA
See chapter 21.

Voltage between pin 6 and 7
At 1mA / 5mA while opto-coupler is low ohmic
While opto-coupler is high ohmic

11. INHIBIT INPUT
Buffering can be disabled or interrupted with the inhibit input (pin 9). Therefore, pin 6 should be connected to thepositive pole of the terminal voltage or to the external control voltage and pin 9 must be connected to thecorresponding negative pole.
Inhibiting the unit also discharges the internal capacitors. Charging of the capacitor is not possible when the buffer
module is in inhibit mode.
Wiring scheme see Fig. 8-2, Fig. 25-1 and Fig. 25-2.
60Vdc (between pin 6 and pin 9)
4mA, current limited

Signal voltage
Signal current
Inhibit mode

Max.
Max.

Isolation voltage

See chapter 21.

The unit does not buffer (or stops buffering) if the voltage between pin 6 and pin 9 ishigher than 10V. Below 6V buffering will function again.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

12. EFFICIENCY AND POWER LOSSES
Efficiency

Typ.

>99%

Power losses

Typ.

1.9W

Power supply mode, 20A output current,
capacitors fully charged
Power supply mode, 0A output current,
capacitors fully charged

13. LIFETIME EXPECTANCY AND MTBF
Calculated lifetime expectancy*)
MTBF**) SN 29500, IEC 61709
MTBF**) MIL HDBK 217F

161 000h*)
457 000h*)
2 348 000h
4 231 000h
405 000h
636 000h
134 000h
198 000h

Stand-by mode, 40°C
Stand-by mode, 25°C
Stand-by mode, 40°C
Stand-by mode, 25°C
Stand-by mode, 40°C, Ground Benign GB40
Stand-by mode, 25°C Ground Benign GB25
Stand-by mode, 40°C, Ground Fixed GF40
Stand-by mode, 25°C Ground Fixed GF25*)

The calculated 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 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.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

14. FUNCTIONAL DIAGRAM
Fig. 14-1 Functional diagram+
Supply +Voltage-

StatusLED

Buffer Capacitor
Charger &Inrush Limiter
ReversePolarity
Protection

Safety and
OverVoltage
Protection

BufferCapacitor
Shut-Down

Buffer Capacitor
Discharger
BufferCapacitor

ChassisGround6 (+)
9 Inhibit
Opto-coupler

Input / Output
Voltage Monitor
Back-up
Level
Selector+-

8 Ready

Ready Monitor

Opto-coupler+-

7 Active

Active Monitor

Opto-coupler

15. TERMINALS AND WIRING
The terminals are IP20 finger safe constructed and suitable for field and factory wiring.

Type
Solid wire
Stranded wire
American Wire Gauge
Max. wire diameter
Wire stripping length
Tightening torqueScrewdriver

Supply voltage, chassis ground
Quick-connect spring-clamp terminals
Max. 6mm2Max. 4mm2Max. AWG 20-10
Max. 2.8mm (including ferrules)
Typ. 10mm / 0.4inch
Not applicableNot applicable

Signals
Pluggable screw terminals
Max. 2.5mm2Max. 2.5mm2
AWG 22-14
2.25mm (including ferrules)
6mm / 0.25inch
0.4Nm / 3.5lb.inch
3mm slotted

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 and
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) Unused terminal compartments should be securely tightened or closed.
e) Ferrules are allowed.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

10/18

UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

16. FRONT SIDE AND USER ELEMENTS
Fig. 16-1 Front side

A Supply Voltage Terminals
Quick-connect spring-clamp terminals, two per polarity+ Positive supply voltage terminal– Negative (return) supply voltage terminal
B Chassis Ground Terminal
Quick-connect spring-clamp terminals
Connection of the chassis to ground (earth) is optionaland only required for a view specific applications.
C Signal Connector
4-pole plug connector with screw termination comprises
the following signals:- “Active” signal, for details see chapter 9.
- “Ready” signal, for details see chapter 10- “Inhibit” input, for details see chapter 11
D Status LED
This green LED indicates that the following information:- OFF: Capacitors are discharged or supply voltage isbelow 44V.
- ON: Capacitors are fully charged- Slow flashing (1.25Hz):
Capacitors are getting charged.
- Fast flashing (10Hz):
Capacitors are getting discharged.
E Back-up Threshold Jumper
Option 1: Fixed mode (Jumper in position 2-3)
The unit switches to buffer mode as soon as the voltage falls
below 45V.
Option 2: Variable mode (Jumper in position 1-2)
Unit switches to buffer mode when input voltage decreases
by 2V. Voltage changes slower than 1.1V/s will be ignored if
the voltage is above 45V. Below 45V buffering starts
immediately.
For more details see chapter 5.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

17. EMCThe buffer module is suitable for applications in industrial environment as well as in residential, commercial and lightindustry environment.
EMC Immunity
for all operating modes
Electrostatic discharge

According to generic standards: EN 61000-6-1 and EN 61000-6-2

Electromagnetic RF field
Fast transients (Burst)

EN 61000-4-3
EN 61000-4-4

Surge voltage on supply
voltage terminals
Surge voltage on inhibit
input, active signal andready signal
Conducted disturbanceEN 61000-4-5

EN 61000-4-2

EN 61000-4-5

EN 61000-4-6

Contact discharge *)8kVCriterion A
Air discharge *)15kVCriterion A
80MHz-2.7GHz
10V/m
Criterion A
Input lines
2kV
Criterion A
Output lines
2kV
Criterion A
Signals lines pin 6, 7, 8, 9 **)2kV
Criterion A+Æ0.5kV
Criterion A+ / - Æ chassis ground
1kV
Criterion A
Not applicable since length of signal wire specified shorter than30m.
0.15-80MHz

10V

Criterion A*) Chassis ground connection earthed (grounded)**) Tested with coupling clamp
Criterions:
A: Buffer module shows normal operation behavior within the defined limits.

According to generic standards: EN 61000-6-3 and EN 61000-6-4
EMC Emission
for standby- and charging
mode
Conducted emission,
IEC/CISPR 16-1-2, IEC/CISPR 16-2-1
Limits for DC power ports acc. EN 61000-6-3
supply voltage
fulfilled
Radiated emission
EN 55011, EN 55022
Class 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.

Switching Frequency

The buffer module has two converters with variable frequencies included.
6 to 740kHz
Charging converter at 48V input (is only active during charging)
The frequency depends on the state of charge of the capacitors
10 to 85kHz
Buffer converter at buffering at 45V
The frequency depends on the output current. The values are
between 10% and 100% of the nominal buffer current

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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48V, 20A, 100MS, BUFFER MODULE

UF-Series

18. ENVIRONMENT
Operational temperature *)Storage temperature
Humidity **)Vibration sinusoidal
Vibration random
Shock
AltitudeOver-voltage category
Degree of pollution
LABS compatibility-25°C to +70°C (-13°F to 158°F)-40 to +70°C (-40°F to 158°F)
For storage and transportation
5 to 95% r.H.
IEC 60068-2-30
2-17.8Hz: ±1.6mm; 17.8-500Hz: 2g
IEC 60068-2-6
2 hours / axis
0.5m²(s³)
IEC 60068-2-64
2 hours / axis
30g 6ms, 20g 11ms
IEC 60068-2-27
3 bumps / direction, 18 bumps in total
0 to 6000m (0 to 20 000ft)
Approvals apply only up to 2000m
III
IEC 62103, EN 62477-1
IIIEC 62103, EN 62477-1, above 2000m altitude2
IEC 62103, EN 62477-1, not conductive
The unit does not release any silicone or other LABS-critical substances and is suitable foruse in paint shops.

*)

Operational temperature is the same as the ambient or surrounding temperature and is defined as the air temperature 2cm below theunit.
**) Do not energize while condensation is present

19. PROTECTION FEATURES
Electrical protection
Over-voltage protection in
buffer mode
Degree of protection
Penetration protection
Reverse polarity protection
Input overvoltage protection
Internal input fuse

Electronically protected against overload, no-load and short-circuits
Typ. 58Vdc
In case of an internal buffer module defect, aMax. 60Vdc
redundant circuit limits the maximum output voltage.
Buffering stops and automatically attempts to restart.
IP 20
EN/IEC 60529> 3.5mm
E.g. screws, small parts
Yes
Max. -60V
No
Not included

20. SAFETY FEATURESClass of protection

Isolation resistance

Chassis ground terminal
resistanceNo classificationaccording to IEC 61140 or
IEC 60950-1 possible> 500MOhm> 500MOhm> 500MOhm< 0.1Ohm

Install the buffer module according to Class III rules

Supply voltage to signal port
Supply voltage to housing
Signal port to housing
Between housing and chassis ground terminal

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

21. DIELECTRIC STRENGTH
The signal port (active and ready signal and inhibit input) is floating and separated from the supply voltage.
Type and factory tests are conducted by the manufacturer. Field tests may be conducted in the field using theappropriate test equipment which applies the voltage with a slow ramp (2s up and 2s down). Connect all poles of thepower port terminals together as well as all poles of the signal port before conducting the test. When testing, set the
cut-off current settings to the value in the table below. The following isolation tests were performed:
Fig. 21-1 Dielectric strength

Type test
SupplyVoltage

A

B

ChassisC

60s

A
500VacB
500VacC
500VacFactory test

5s

500Vac

500Vac

500VacField test

5s

500Vac

500Vac

500Vac

> 1mA

> 1mA

> 1mA

Cut-off current setting

Active and Ready Signal
Inhibit Input

22. APPROVALSEU Declaration of Conformity

The CE mark indicates conformance with the EMC directive

IEC 60950-1
2nd Edition

CB Scheme,
Information Technology Equipment

UL 60950-1
2nd Edition

Recognized for use as Information Technology Equipment,
U.S.A. (UL 60950-1) and Canada (C22.2 No. 60950-1);
E-File: E137006
Listed for use as Industrial Control Equipment;
U.S.A. (UL 508) and Canada (C22.2 No. 107-1-01);
E-File: E198865

UL 508IND. CONT. EQ.

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 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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UF20.481
UF-Series

48V, 20A, 100MS, BUFFER MODULE

23. PHYSICAL DIMENSIONS AND WEIGHT
Width
HeightDepth

WeightDIN-rail
Housing material
Installation clearances

64mm
2.13’’
124mm 4.88’’102mm 4.02’’
The DIN-rail height must be added to the unit depth to calculate the total required
installation depth.
740g / 1.63lb
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. 23-1 Front viewFig. 23-2 Side viewOct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

15/18

UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

24. ACCESSORIES

24.1. ZM1.WALL - WALL MOUNTING BRACKETThis bracket is used to mount the buffer module on a wall without utilizing a DIN-Rail.
The two aluminum brackets and the black plastic slider of the unit have to be detached, so thatthe steel brackets can be mounted.

Fig. 24-1 Wall mounting

Fig. 24-2 Mounting Dimensions - Wall mounting bracket

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

16/18

UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

24.2. ZM14.SIDE - SIDE MOUNTING BRACKETThis bracket is used to mount the buffer module 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 thatthe 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.

Fig. 24-3
Side mounting without DINrail brackets

Fig. 24-4
Side mounting with DIN-railbrackets

Fig. 24-5
Mounting Dimensions
Side mounting bracket

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0Germany

17/18

UF20.481
48V, 20A, 100MS, BUFFER MODULE

UF-Series

25. WIRING DIAGRAMS

L
N
PE

optional+- +-IN 1 IN 2

Adj
DC-OK
Overload

External
Voltage Source

Inhibitoptional

Oct. 2016 / Rev. 2.0 DS-UF20.481-EN
All parameters are specified at 48V, 20A, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0+Buffered
Load

6 +

OUT

+ -

UF20
Back-up
Buffer Threshold
Module7 Active

YR2
Redundancy
ModuleL N PEL
N
PE- - ++
StatusPower
Supply6 +7 Active

8 Ready

9 Inhibit

6 +7 Active

UF20
Back-up
Buffer Threshold
Module++ - +UnbufferedLoad

8 Ready

Status8 Ready

L N PEL
N
PE- - ++

Status

UF20
Back-up
Buffer Threshold
ModulePower
SupplyReady
Relay, lamp or signal

optional

Fig. 25-4 Decoupling of buffered branches- - ++

9 Inhibit

Load

Adj
DC-OK
Overload

ActiveRelay, lamp or signal

L N PE+

optional++ - -

UF20
Back-up
Buffer Threshold
ModulePower
SupplyFig. 25-3 Paralleling of buffer modules+-

Status

6 +Inhibit

Ready
Relay, lamp or signal

ActiveRelay, lamp or signal

Load

-

- - ++Adj
DC-OK
Overload+-

9 Inhibit

L
N
PE

6 +

9 Inhibit

L N PE

7 Active

UF20
Back-up
Buffer Threshold
ModulePower
Supply8 ReadyLoad++ - -

Status

7 Active- - ++Adj
DC-OK
Overload

9 Inhibit++ - +-

Fig. 25-2 Signals supplied from an external voltage source

8 ReadyFig. 25-1 General wiring diagram

Germany

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