PCU-S1 The PCU-S1 is a power supply module with a 3U Eurocard form factor intended for use as a Bus and Bias supply for the low voltage series of Western Servo Design amplifiers (e.g., BLU, LDU and PDU). It can be used in a Eurorack (or "VME") style chassis or as a stand alone unit.

The PCU-S1 contains a DC Bus unregulated output, a regulated Bias Supply (12VDC), a 12VDC output for cooling fans, and a built-in shunt regulator. When PWM amplifiers are used, the shunt regulator prevents back EMF generated by the motors from damaging components in the Bus Supply and amplifiers.

An optional backplane is available to allow quick and easy access to the inputs and outputs for the power supplies and the shunt regulator. This greatly simplifies implementing the PCU-S1 in a motion control system.


  • Eurocard 6U Form Factor
  • Contains Bus Supply, Bias Supply and 12VDC Fan Supply
  • Built-In Shunt Regulator
  • Front Panel Status LEDs for Bias Supply, Fan Supply and Shunt Regulator Fuse
  • 30 Ampere Continuous Output Current
  • Optional Backplane Simplifies System Connection
  • Advanced Design, High Quality and High Reliability at a Lower Cost


Standard Models:


Maximum AC Input Voltage* 43VAC RMS
Minimum AC Input Voltage 19VAC RMS
Bus Voltage Output Approximately 1.4 x VAC in
Bus Output Current* 30A Continuous
Bias Voltage Output** +12VDC @ 2A, -12VDC @ 1A
Cooling Fan output 12VDC @ 1A
Shunt Regulator Load 7Ohms @ 50W or more (only needed when Bus Voltage is higher than 40 VDC)
Weight 1.16 Lbs (2.55 Kg)
Recommended Chassis CH3U, CH6U Eurocard
Available Accessories MA3U-P1-1 Backplane

*Do not connect 120VAC power to the AC input of the PCU-S1. Contact Western Servo for more information about appropriate step-down transformers. Use the PSU-S1 model Power Supply if higher Bus Voltages and direct connection to AC Mains (120 to 240VAC) are required.

**All ratings with forced air cooling to maintain 40C heat sink temperature. Failure to keep constant air flow to the heat sink will reduce the output current capacity and may result in damage to the unit.

Note: Specifications subject to change without notice.

Ordering Information

Product Order Number
PCU-S1-6/30 Power Supply 60VDC/30A Cont. WS-009-0001
ACC-V1X Backplane WS-011-0001

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All data sheets are in Adobe Acrobat format.