PowerBox OFI1200A Series User manual

POWERBOX Industrial Line
OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
1
www.prbx.com 2022.07.21
Specifications are subject to change without notice.
Table of Contents
1. Assembling and Installation Method ......................................................... 1
1.1 Mounting method ................................................................................... 1
1.2 Isolation from conductive enclosure.................................................... 2
1.3 Installation to fulfil EMC requirement.................................................. 2
2. Derating........................................................................................................... 2
2.1 Derating curve by input voltage............................................................ 2
2.2 Temperature measuring point.............................................................. 2
3. Wiring............................................................................................................... 3
3.1 Wiring input connector .......................................................................... 3
3.2 Wiring output terminal ........................................................................... 3
3.3 Wiring function connector..................................................................... 4
3.4 Jumper factory setting........................................................................... 4
3.5 Output ripple and ripple noise measurement.................................... 4
4. Functions ........................................................................................................ 4
4.1 Input voltage range................................................................................. 4
4.2 Inrush current limiting............................................................................ 4
4.3 Over current protection.......................................................................... 5
4.4 Over voltage protection.......................................................................... 5
4.5 Thermal protection ................................................................................. 5
4.6 Output voltage adjustment.................................................................... 5
4.7 Remote ON/OFF..................................................................................... 6
4.8 Remote sensing....................................................................................... 7
4.9 Adjustable constant current range ...................................................... 7
4.10 Power good (PG)................................................................................... 8
5. Series / Parallel Operation........................................................................... 8
5.1 Series operation...................................................................................... 8
5.2 Parallel operation .................................................................................... 9
5.3 Redundancy operation.........................................................................10
6. Life Expectancy and Warranty...................................................................11
6.1 Life Expectancy .....................................................................................11
6.2 Warranty .................................................................................................11
7. Options..........................................................................................................11
7.1 Option -N: with Metal cover ................................................................11
7.2 Option -O: with Active ORing..............................................................11
1. Assembling and Installation Method
1.1 Mounting method
OFI1200A series should be mounted to a heatsink or enclosure which
has sufficient thermal capacity to be cooled by conduction cooling.
OFI1200A has 10 of 4.5mm diameter mounting holes, to keep uniform
thermal conductivity, use at least 6 mounting holes as shown in Fig.
1.1. Using all 10 mounting holes is recommended.
Minimum Recommended
Fig. 1.1 Mounting hole requirement
A thermal interface material such as thermal pads or thermal grease
shall be used to ensure proper cooling of the power supply.
OFI1200A28 and OFI1200A48 without option -O (Active ORing), have
open holes in the aluminium baseplate. When using grease as thermal
interface material, it could flow to the inside of unit. This is not
dangerous, but not desirable. We recommended to not apply grease
closer than 10mm from these holes. See Fig. 1.2 for location of open
holes.
Fig. 1.2 The Location of open hole on aluminium baseplate (Bottom
view)
Remarks:
- There is no open holes in aluminium baseplate on units with option -
O.
23.5mm
80mm
12mm
32mm
20mm
Output
Input
Location of open holes

POWERBOX Industrial Line
OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
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1.2 Isolation from conductive enclosure
There are dangerous voltages inside of the unit. Special attention
needs to be considered when installing the open type of unit.
Ensure proper isolation distances between the components and
conductive enclosure.
d1, d2 = 4mm min
If sufficient isolation distances cannot be secured, an isolation sheet
shall be added between a components and external surfaces.
Fig. 1.3 Isolation distance
To optimize cooling airflow around the unit, ensure that the clearance
between the unit and surrounding objects is as large as possible.
Remarks:
- In case without option -N (with cover) and the enclosure made by
combustible material, the distance d2 shall be more than 13mm
because Varistor is implemented inside of the unit. This requirement
comes from the safety approvals.
1.3 Installation to fulfil EMC requirement
To ensure the best EMI-performance, the equipment should be
mounted inside an earthed metal box.
If it is not possible, an install power supply and a load on an earthed
metal plate.
Input cables should be twisted and places as close to the metal
enclosure as possible.
Output cables of positive (+) and negative (-) should be twisted and
shall be separated from input cables as much as possible.
If radiation from input or output cables are an issue, use appropriate
EMC ferrite clamp on the cables.
When function pins are connected to an user accessible point (i.e.,
panel switch, indicator circuit etc.), these must be protected from
electrostatic discharging.
2. Derating
2.1 Derating curve by input voltage
Fig. 2.1 Derating curve by input voltage
Remarks:
- OFI1200A12 has no input voltage derating.
- The over current protection will be activated as following Fig.2.1.
2.2 Temperature measuring point
For reliable and safe operation, make sure the maximum component
temperature given in Table 2.1 are not exceeded.
The temperature measuring points are shown in Fig. 2.2.
Operating at the maximum temperature rating results in 3-years life
expectancy.
Table 2.1 Maximum operating temperature
Point
Part name
Part
Ref.
Maximum Temperature [°C]
Standard
Optional: N
A
Baseplate of Internal
power supply module
-
See Fig. 2.3
See Fig. 2.3
B
Line filter
L102
110
100
C
Aluminium
Electrolytic Capacitor
C405
88
88
D
Aluminium
Electrolytic Capacitor
C501
89
89
Fig. 2.2 Temperature measuring points
d1
d1
d2
(Side view)
B
D
A
C
(Top view)

POWERBOX Industrial Line
OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
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Fig. 2.3 Derating curve of point A (baseplate temperature)
Remarks:
Operation in the hatched area may cause significant level of ripple and
ripple noise.
<Temperature measurement with cover option>
To measure a temperature of internal components in units with option
-N (with cover), it is necessary to remove the cover to apply
thermocouples on measuring points.
To remove the cover, remove cables from input terminal and remove 4
screws on each corner.
There are an isolation sheet and gap pads on the input filter. When the
cover is re-installed, make sure that the isolation sheet and gad pads
are properly located.
Fig. 2.4 Screws to be removed for temperature measurement
3. Wiring
3.1 Wiring input connector
(1) Built-in fuse
The two 16 ampere AC fuses are built-in on AC(L) in parallel.
(2) Wire
Connection capability of the input connector.
Input connector type : MKDS 5/ 3-9,5 (1714984)
(Phoenix Contact)
Connector cross section solid : 0.2 mm2–6 mm2
Connector cross section flexible : 0.2 mm2–4 mm2
Conductor cross section (AWG) : AWG 24 –10
Conductor cross section (flexible, with ferrule)
: 0.25 mm2–4 mm2
Stripping length : 8mm
Torque : 0.5 –0.6 Nm
An input current is dependent on input voltage and output current.
Choose the appropriate thickness for the input wire.
Influence against noise is improved if the input wires are twisted. In
addition, make sure that input and output wires are separated.
(3) FG terminal
The FG terminal on input connector shall be Functional Ground.
Make sure that the mounting hole for protective earthing on the
baseplate is properly connected, as required for class I equipment.
3.2 Wiring output terminal
The assembly torque for output terminal screws.
Screw size : M6
Recommended screw torque : 3.8 Nm
At -40°C operation, an external output capacitor needs to be added to
ensure stable output voltage during start-up. Table 3.1 shows a
recommended an external output capacitor.
Table 3.1 Recommended external output capacitor
Models
Value
OFI1200A12
7,800 µF
OFI1200A28
3,000 µF
OFI1200A48
1,360 µF
0
50
100
-40 -20 0 20 40 60 80 100
Load factor [%]
Baseplate temperature [˚C]
(75)
(75)
OFI1200A28,OFI1200A48
Vin = 170～305VAC
OFI1200A28,OFI1200A48
Vin = 85～170VAC
(65)
(95)
OFI1200A12
(60)
Screw locations

POWERBOX Industrial Line
OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
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3.3 Wiring function connector
Fig. 3.1 shows the pin assignment and Table 3.2 states the pin
configuration of function connector X506 and X507.
Fig. 3.1 X506 and X507 Pin assignment
Table 3.2 Function of connector X506 and X507
Pin No.
Name
Function
1
CB
Refer to Section 5.2
2
-S
Refer to Section 4.8
3
PG
Refer to Section 4.10
4
RC1
Refer to Section 4.7
5
ITRM
Refer to Section 4.9
6
VTRM
Refer to Section 4.6
7
NC
8
PGG
Refer to Section 4.10
9
+S
Refer to Section 4.8
10
RC2
Refer to Section 4.7
<Connector information>
Part number : 87831-1041 (Molex)
<Appropriate mating connector and pin>
Part number : 51110-1056 (Molex)
Pin : 50394-8051 (Molex)
For connecting X506 and X507, H-SN-61 (Manufactured by Cosel) is
available.
https://en.cosel.co.jp/product/optionparts/H-SN-61/
Remarks:
- An incorrect connection of functional connector may cause damage
on an internal circuit. Make sure the connection is properly made.
3.4 Jumper factory setting
Jumpers on X503, X504 and X601 are placed as shown in Fig. 3.2 at
the factory.
Fig. 3.2 Jumper placement at factory
3.5 Output ripple and ripple noise measurement
The specified ripple and ripple noise are measured by the method
shown in Fig.3.3.
Fig.3.3 Method of Measuring Output ripple and ripple noise
Remarks:
- When the ambient temperature is lower than -20°C, the output ripple
may become unstable during heating up.
4. Functions
4.1 Input voltage range
The unit operates with an input voltage range between 85 - 305 Vac.
The voltage range for a valid safety approval is 100 - 277 Vac
(50/60Hz).
Remarks:
- Be aware that use of voltages other than those listed above may
result in the unit not operating according to specifications or may
cause damage or dangerous situations. Avoid square waveform input
voltage, commonly used in UPS and inverters.
4.2 Inrush current limiting
There is a built-in inrush current limiting circuit.
If a switch is needed on the input side, select one that can withstand
the input inrush current.
The thyristor technique is used in the inrush current limiting circuit.
Avoid repeatedly turning the power ON/OFF within a short period of
time, operates the inrush current limiting becomes inoperative.
When the input power is turned on, the primary inrush current and
secondary inrush current will be generated due to the thyristor
technique used for the inrush current limiting circuit.
OFI1200A Load
C1
C2
+Vout
-Vout
300mm
Oscillo
scope
+
1.5m 50Ω
Coaxial Cable
C3
R
C1 : 0.1uF
C2 : 47uF
C3 : 4,700pF
R : 50Ω
9
10
2
1
Input
Output
CB
PG
ITRM
NC
+S
-S
RC1
VTRM
PGG
RC2

POWERBOX Industrial Line
OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
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4.3 Over current protection
The over current protection is built in and comes into effect when
drawing over 105% of the rated current.
The over current protection prevents the unit from short circuit and
over current condition. The unit automatically recovers when the fault
condition is cleared.
When the output voltage drops at over current, the average output
current is reduced by hiccup operation of the unit.
4.4 Over voltage protection
The over voltage protection circuit is built in. If the over voltage
protection circuit is activated, shut down the input voltage, wait a
certain time and turn on the AC input again to recover the output
voltage.
The recovery time is 10 seconds or more.
Remarks:
- Note that devices inside the unit might fail if voltage of higher than
rated output voltage is applied to output terminal. This could happen
when the user tests the over voltage performance of the unit.
- With option -O (Active ORing) circuit disconnects the output from the
external voltage. Therefore, over voltage protection will not be
activated. Therefore, it is not possible to test over voltage performance
for an option -O unit by applying external voltage.
4.5 Thermal protection
When the baseplate temperature exceeds the maximum temperature,
thermal protection will be activated and shut down the output.
When the thermal protection is activated, turn off the input voltage and
eliminate all the overheating conditions. To recover the output voltage,
let the unit cool down before turning on the input voltage again.
4.6 Output voltage adjustment
The output voltage can be adjusted by means of either the built-in
potentiometer (R513) or by applying an external voltage source.
(a) Adjustment by built-in potentiometer
To increase output voltage, turn R513 clockwise. To decrease the
output voltage, turn it counter clockwise.
The output voltage adjustment range by R513 is shown below.
Model Output Output
Number Voltage Voltage adj.
OFI1200A12 12VDC 4.2 –14.4VDC
OFI1200A28 28VDC 9.8 - 33.6VDC
OFI1200A48 48VDC 16.8 - 57.6VDC
WARNING:
Adjusting the built-in potentiometer (R513) fully counter clockwise and
applying external voltage will create a short circuit that may damage
the unit.
The output voltage must be adjusted within ±20% of the nominal by
R513 before applying external voltage.
(b) Adjustment by external voltage source
To adjust the output voltage by an external voltage source, apply it
between VTRM and -S terminal.
Use a low impedance source as external voltage. The internal circuit of
VTRM is shown in Fig. 4.1.
Remarks:
- Do not apply an external voltage lower than -0.3V or greater than
5.0V.
Fig. 4.1 VTRM internal circuit
The output voltage can be calculated by the following equation when
the voltage is applied to the VTRM terminal.
Output voltage [V]=
The voltage between
VTRM and -S [V]
2.5 [V] ×Rated output voltage [V]
Fig. 4.2 Output Voltage by VTRM
OFI1200A
VTRM
-S
5V
4.7kΩ
10kΩ
0.01uF
R513:
10k
External voltage source
Vref

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OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
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4.7 Remote ON/OFF
Remote ON/OFF is built in. Remote ON/OFF is operated by applying a
voltage between RC1 and RC2 terminal. The Internal circuit and
function of X601 are shown in Fig. 4.3.
When the output shuts off by the over voltage protection or thermal
protection, it can be recovered by toggling Remote ON/OFF signal.
The remote control logic can be changed with X601. And the isolation
between the RC circuit and any other is dependent on the position of
X601’s jumper. Those details are shown in Table 4.1 and Fig. 4.4.
Table 4.1 Remote Control Logic
No.
Item
Remote Control Logic
1
Connection
method
Fig. 4.4(a)
Fig. 4.4(b)
Fig. 4.4(c)
2
Isolation
INPUT - RC
OUTPUT - RC
INPUT –RC
INPUT - RC
3
Reference
pin
RC2
-S
-S, RC2
4
Output
ON
SW OPEN (0.1mA max)
SW SHORT
(0.5V max)
5
Output
OFF
SW SHORT (2mA min)
SW OPEN
(0.1mA max)
Fig. 4.3 The Internal circuit and function of X601
(a) Use external voltage source (Positive logic)
External resistor Rrc value shall be decided by following formula.
Vext[V]-1.4
2[mA] -150[Ω] > Rrc[Ω]> Vext[V]-0.9 12[mA] -150[Ω]
(b) Change position of X601 (Positive logic)
In the case of this connection example, the control current (I_RC1)
flows up to 9.7mA.
(c) Change position of X601 (Negative logic)
In the case of this connection example, the control current (I_RC1)
flows up to 9.7mA.
Fig. 4.4 Example of connecting remote ON/OFF circuit
Remarks:
- Be careful not to connect RC1 and RC2 opposite. It may cause a
failure of unit.
- The sink current of RC1 must be kept up to 12mA.
- Do not use RC1 terminal any other purposes except remote control.
OFI1200A
150
RC1
RC2
-S
Jumper
Internal AUX
12V typ.
X601
1.1k
(a) The position of jumper:
OFI1200A
150
RC1
RC2
-S
Jumper
Internal AUX
12V typ.
X601
1.1k
(b) The position of jumper:
OFI1200A
RC1
RC2
-S
OFF
OUTPUT
ON
X601 Position
I_RC1
OFI1200A
RC1
RC2
-S
ON
OUTPUT
OFF
X601 Position
I_RC1
OFI1200A
RC1
RC2
-S
Vext
Rrc
ON
OUTPUT
OFF
X601 Position

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OFI1200A Series
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AC/DC Baseplate power supply
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4.8 Remote sensing
Remote sensing is built in. When remote sensing is not used, make
sure that jumpers are placed on X503 and X504 as shown in Fig.
4.5(a).
When using remote sensing function, place jumpers on X503 and
X504 as shown in Fig. 4.5(b), then connect +S and -S terminal on X506
or X507 to sensing point.
Fig. 4.5 X503 and X504 Jumper position
Remarks:
- Twisted-pair wires or shielded wires should be used for sensing wire.
- Use proper cable thickness for the wiring between the unit and load.
The line drop between the unit and load should be less than 0.5V. The
voltage between +Vout and -Vout should remain within the output
voltage adjustment range.
- If the sensing lines become short circuited, a high current will occur,
and the sensing circuit may be damaged. The problem can be
prevented by installing current limiting the component near the load.
- As wiring or load impedance may generate oscillation or large
fluctuation in output voltage, make sure enough evaluation is given in
advance. If the unstable condition occurs, try adding C1 –C3 and R1.
Fig. 4.6 When using remote sensing function
4.9 Adjustable constant current range
The output current for the constant current can be adjusted by
connecting external resistors to ITRM or by applying a voltage
externally. Meanwhile, the Hiccup mode of the short circuit protection
will be disabled.
(1) Constant current adjustment by potentiometer
By connecting the external potentiometer as shown in Fig. 4.7, output
current for constant current becomes adjustable.
Wiring to the potentiometer should be as short as possible. As the
ambient temperature fluctuation characteristics deteriorate
depending on the types of resistors and potentiometers, use resistors
and a potentiometer of the following specifications:
Potentiometers: Cermet type, coefficient less than ±300ppm/℃
Fig. 4.7 Connection for CC by external potentiometer
(2) Constant current adjustment by external voltage
By applying a voltage externally to ITRM, output current for constant
current becomes adjustable.
When the ITRM terminal voltage is set at less than 2.5 V, the constant
current set value can be changed.
Output current [A]=
The voltage between
ITRM and -S [V]
2.5 [V] ×Rated output current [A]
Fig. 4.8 ITRM internal circuit
Remarks:
- If the output voltage becomes less than 5% of the rated voltage
during constant current operation, the output voltage may become
unstable.
- When the output current adjustment is not used, keep ITRM pin
open.
- Do not set the external applied voltage to -0.3 V or less, and 5.0 V or
more.
OFI1200A Load
C2
+Vout
-Vout
+
-S
+S
R1
Wire the sensing lines as close as possible
C1
+
+
C3
OFI1200A
ITRM
-S
External potentiometer
10[kΩ]
(a) Disable remote sensing
(Factory setting)
(b) Enable remote sensing
C1 –C3: 100 –2,200 [μF]
R1: 1 –4.7 [Ω]

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OFI1200A Series
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AC/DC Baseplate power supply
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4.10 Power good (PG)
By using power good signal (PG), it is possible to monitor the unit
whether normal operation or abnormal operation. The PG signal is
“Low” when the unit operates correctly. The signal turns to “High”
when the unit stops.
The PG circuit is designed as shown in Fig. 4.9. The sink current of PG
is 1mA max.
The circuit of the PG (PG, PGG) is isolated from input, output, FG, and
various function terminals.
Fig. 4.9 Internal circuit of PG
The details of PG signal are shown in Table4.3, Fig. 4.10, and Fig.
4.11.
Table 4.3 Specification of PG
No.
Item
PG
1
Function
Normal operation “Low”
The unit stops “High”
2
Base pin
PGG
3
Level voltage “L”
0.5V max at 1mA
4
Level voltage “H”
Open corrector
5
Maximum sink current
1mA max
6
Maximum applied voltage
50V max
Fig. 4.10 PG signal sequence
Fig. 4.11 PG signal sequence with circuit protections
5. Series / Parallel Operation
5.1 Series operation
Series operation is possible by connecting the output of two or more
power supplies as shown in Fig. 5.1.
Fig. 5.1 Example of Series operation
Output current in series connection should be lower than the lowest
rated current in each unit.
When one of unit’s output becomes short circuit in series operation,
high voltage may be applied to rest of units. To avoid further damages,
consider adding a protection method that immediately stops
operation.
Make sure that the combined total output voltage is less than 120Vdc.
The classification of Electrical energy source of output voltage for
OFI1200A12 and OFI1200A28 are ES1, and OFI1200A48 is ES2.
Therefore, make sure the safety requirement when total output voltage
exceeds 60Vdc.
(a)
(b)
ACin
ON
OTP Over Current
Protection
V1: 60% of the set output voltage
V2: 20% of the set output voltage
RC
ON
RC
OFF
OVP
RC
ON
RC
OFF
Hiccup
0V
0V
V1
V2
OFF
ON
Hight
Low
12V typ.
0V
AC Input
voltage
Output
voltage
Remote
ON/OFF
PG
Internal
AUX
ACin
ON
RC
OFF
RC
ON
Adjustable
Constant
Current
Adjustable
Volgate
ACin
OFF
CC-control
CV-control
V1: 60% of the set output voltage
V2: 20% of the set output voltage
0V
0V
V1
V2
OFF
ON
Hight
Low
12V typ.
0V
AC Input
voltage
Output
voltage
Remote
ON/OFF
PG
Internal
AUX

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OFI1200A Series
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5.2 Parallel operation
(a) Wiring for parallel operation
Parallel operation is possible by connecting the units as shown in Fig.
5.2 and Fig. 5.3. Terminal -S, CB, and VTRM of function connecter
X506 or X507 of each unit must be connected to each other.
To wire the terminal -S, the jumper position of X504 must be changed
for all units as Fig. 5.2 and then, the cable must be connected to -Vout
from only one unit shown as Fig.5.3. The cables must be twisted or
bundled with a cable of CB and VTRM. If not, the output voltage may
become unstable or fluctuate.
If the temperatures of aluminium baseplate are different in the unit in
parallel operation, the difference of output current becomes large.
Consider the thermal design to equalize aluminium baseplate
temperatures.
(i.e., attaching a single heatsink etc)
Total current must not exceed the value calculated by the following
equation, and total number of units should be no more than 9 pieces.
(Output current at parallel operation)
= (the rated current per unit) x (number of unit) x 0.9
Fig. 5.2 X504 Jumper position
Fig. 5.3 Example of wiring for parallel operation
Remarks:
- Make sure that the wiring impedance of a load from each unit
becomes even.
- A voltage drop from -Vout of unit to the connected point of terminal -
S should be less than 0.5V for stable control.
- If the output current is less than 2% of the rated current, the output
voltage ripple will be large.
- If all paralleled unit need to start up at the same time, remote control
function shall be used.
(b) Output voltage adjustment in parallel operation
The output voltage can be adjusted by the built-in potentiometer
(R513) or by applying an external voltage source in parallel operation.
By using R513, it is possible to adjust all output voltages in the unit by
the master unit. Select one unit as the master and turn the R513 of the
other unit (slave) clockwise to the maximum output voltage adjustment
following the datasheet.
By using an external voltage source, the examples of circuits are
shown in Fig. 5.4. Refer to section 4.6 ”Output voltage adjustment”
how to use this function.
Fig. 5.4 Example of connecting output voltage adjustment circuit with
external voltage in parallel operation
OFI1200A
OFI1200A Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
VTRM
VTRM
Vref
Wire as close as possible
External voltage source
(a) Factory setting
(b) For wiring parallel operation
OFI1200A
N
L
FG
OFI1200A
N
L
FG
OFI1200A
N
L
FG
Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
AC IN
FG
VTRM
VTRM
VTRM
Wire as close as possible
Wire as close as possible

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(c) Wiring for parallel operation with remote sensing
Example of connecting remote sensing circuits in parallel operation
are shown in Fig. 5.5. Refer to section 4.8 "Remote sensing" how to
use this function.
Fig. 5.5 Example of connecting remote sensing circuit
(d) Wiring for parallel operation with remote control
Example of connecting remote ON/OFF circuits in parallel operation
are shown in Fig. 5.6 and Fig. 5.7. Refer to section 4.7 "Remote
ON/OFF" how to use this function.
In this case, accumulated current (N×I_RC1) flows to the control
switch.
Fig. 5.6 Example of connecting remote ON/OFF circuit
Fig. 5.7 Example of connecting remote ON/OFF circuit
(e) Wiring for parallel operation with constant current adjustment
The constant current adjustment can be used in parallel operation. By
changing the ITRM voltage of one unit, the constant current adjustable
for all of units.
It is not necessary to connect the ITRM terminals together. Examples
of connecting constant current circuit in parallel operation are shown
in Fig. 5.8 and Fig. 5.9. Refer to section 4.9 "Adjustable constant
current range " how to use this function.
Fig. 5.8 Example of connecting constant current circuit with a
potentiometer
Fig. 5.9 Example of connecting constant current circuit with an
external voltage
5.3 Redundancy operation
By choosing option -O, ORing MOSFET is implemented into the unit.
Therefore, it is possible to connect each output directly for N + 1
redundancy operation.
See section 7.2.
・・・
Vrc
OUTPUT
OFF
N x I_RC1
I_RC1
I_RC1
I_RC1
Rrc
OFI1200A
RC1
RC2
-S
X601 Position
Rrc
OFI1200A
RC1
RC2
-S
X601 Position
Rrc
OFI1200A
RC1
RC2
-S
X601 Position
OFI1200A
RC1
RC2
-S
X601 Position
・・・
OUTPUT
ON
OFF
N x I_RC1
OFI1200A
RC1
RC2
-S
X601 Position
OFI1200A
RC1
RC2
-S
X601 Position
I_RC1
I_RC1
I_RC1
OFI1200A
OFI1200A Load
+Vout
-Vout
-S
+S
CB
+Vout
-Vout
-S
+S
CB
Sensing point
VTRM
VTRM
Wire as close as possible
External potentiometer
OFI1200A
OFI1200A Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
VTRM
VTRM
Wire as close as possible
ITRM
ITRM
OFI1200A
OFI1200A Load
+Vout
-Vout
-S
CB
+Vout
-Vout
-S
CB
VTRM
VTRM
Vref
Wire as close as possible
External voltage source
ITRM
ITRM

POWERBOX Industrial Line
OFI1200A Series
1200W Single output
AC/DC Baseplate power supply
11
www.prbx.com 2022.07.21
Specifications are subject to change without notice.
6. Life Expectancy and Warranty
6.1 Life Expectancy
A life expectancy is strongly dependent to operating temperature and
cooling conditions.
To make sure the life expectancy, measure temperature of Electrolytic
capacitors shown in Fig. 6.1 and calculate by following formula.
L=L105×2105-Tcap
10
where
L: Life expectancy [hour]
L105 : Endurance at 105°C [hour], see table 6.1
Tcap : Temperature of Electrolytic capacitor[°C]
Table 6.1 Endurance of Electrolytic capacitor
Item
C405
C501
L105
Endurance at 105[°C]
12,000h
8,000h
Fig. 6.1 Temperature measuring point for Life expectancy
6.2 Warranty
Warranty term is 3 years.
7. Options
7.1 Option -N: with Metal cover
The metal cover option improves radiated noise from the unit and
gives better mechanical protection.
7.2 Option -O: with Active ORing
ORing MOSFET is implemented. It enables to connect each output of
same model to use as redundancy operation without additional
components. The differences between with/without option -O are
shown below.
(a) Output voltage adjustment range
The output voltage adjustment range by external voltage source with
the option -O is shown as below.
Model Output Output
Number Voltage Voltage adj.
OFI1200A28-O 28VDC 5 - 33.6VDC
OFI1200A48-O 48VDC 5 - 57.6VDC
WARNING:
Adjusting the output voltage less than 5V may cause heating internal
ORing MOSFET up. If need to adjust it lower than 5V, contact us.
(b) Parallel and N + 1 Redundancy operation
Parallel operation and N + 1 redundancy operation are possible with
option -O.
In these connection, the remote sensing and constant current function
cannot be used. Because the redundancy will not be working on failed
condition with using those functions.
If those function are needed, choose the standard model of OFI1200A.
Wiring for parallel and N + 1 redundancy operation, see Fig. 5.3. Even
though the remote sensing function is not used, terminal -S must be
wired with an appropriate connection as following Fig. 5.3.
Remarks:
- To adjust the output voltage by the built-in potentiometer (R513), the
output voltage setting of each unit must be equalized. Otherwise, the
output voltage might be changed to unintentional voltage in case one
or more units failed.
- When choosing option -O for N +1 redundancy, make sure that the
total load current does not exceed the rated current of a single unit.
- When replacing one or more units in N + 1 redundant operation, the
input voltage must be shut out. A hot swap is not supported for
OFI1200A.
C501
C405