1. General Information

• Manufacturer: Reliance Electric (Baldor-Reliance / Rockwell Automation)

• Part Number: 0-51444 (051444)

• Product Type: Power Supply & Driver Board / Phase Sequence Board

• Application: Reliance DC variable speed drives (legacy ImPak / VS series)

• Function: Provides isolated control power, SCR gate drive pulses, and phase sequence logic for drive main power bridge

• Status: Obsolete (OEM discontinued); available as used / refurbished

• Warranty: 6–12 months (refurbished units)

2. Electrical Specifications

• Input Voltage: 115 / 230 VAC, 50/60 Hz (selectable via jumper)

• Output Control Voltages:

  • +5 VDC (logic)

  • ±12 VDC (analog)

  • 24 VDC (auxiliary)

• Gate Drive Output: 6–channel isolated SCR firing pulses (phase‑sequenced)

• Isolation Rating: 2500 VAC (input‑to‑output isolation)

• Onboard Protection:

  • Fuse protection (primary & secondary)

  • Overcurrent & short‑circuit protection

  • Transient voltage suppression (TVS diodes, metal‑oxide varistors)

• Voltage Regulation: ±1.5% at full load

• Max Output Power: ~75 W

3. Physical & Mechanical

• Dimensions (W × H × D): 254 × 178 × 32 mm (10.0 × 7.0 × 1.25 in)

• Weight: Approx. 0.7 kg (1.5 lbs)

• Construction: Industrial‑grade PCB with conformal coating (dust/moisture resistance)

• Key Components:

  • 3 large power transformers

  • 3 wound induction coils

  • Power resistors, fusible resistors, zener diodes, power transistors

• Connection: Edge‑card connector (direct plug‑in to drive backplane)

4. Environmental Ratings

• Operating Temperature: 0°C to +50°C (32°F to 122°F)

• Storage Temperature: -20°C to +70°C (-4°F to 158°F)

• Humidity: 5%–95% RH, non‑condensing

• Vibration: Industrial grade (suitable for cabinet mounting)

5. Compatibility

• Matched Main Control Board: 0-51381 series

• Matched Gate/Trigger Boards: 0-51419, 0-51378, 0-51422, 0-51423

• Matched Interface Board: 0-51385

• Cross Reference: Direct replacement for original 0-51444; designed for phase‑sequence synchronization in multi‑axis drive systems

6. Installation Notes

1. Disconnect all AC/DC power before installation or service.

2. Align board with backplane slot and insert firmly (avoid bending edge connector pins).

3. Verify input voltage jumper setting matches site supply (115V or 230V).

4. Torque all power wiring terminals to manufacturer specifications before energizing.

5. Check for loose components or damaged insulation after installation.