1. General Information

• Part Number: 518791, 0-51879-1

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

• Series: FlexPak / MinPak / MaxPak / HR2000 DC Drives, CardPAK Rack System

• Type: CPU – Main Control & Logic Processing Board

• Function: Drive sequencing, speed/ current regulation, I/O processing, fault diagnostics, communication interface for DC drive systems

• Status: Obsolete; refurbished / NOS available

• Mounting: 3U Eurocard for CardPAK rack

• Cross-reference: 0-51879-3 (enhanced memory), 0-51879-5 (extended I/O)

2. Electrical Specifications

• Backplane Supply: ±15 VDC, +5 VDC (logic), 24 VDC auxiliary

• Power Consumption: ≤ 15 W

• Processor: 8-bit industrial CPU (Reliance proprietary architecture)

• Memory:

  • RAM: 8 KB (volatile)

  • ROM: 32 KB (firmware, non-volatile)

• Control Loops: 2 independent PID loops (speed, current)

• Input Signals:

  • Speed Reference: 0–10 VDC

  • Current Feedback: 0–5 VDC

  • Digital Inputs: 8-channel (24 VDC logic)

• Output Signals:

  • Firing Angle: 0–10 VDC (0–180°)

  • Digital Outputs: 6-channel (relay/transistor, 24 VDC)

• Communication: Proprietary serial link (drive-to-drive)

• Isolation Voltage: 1500 VAC (logic-to-power)

• Adjustments: Onboard trimpots for Speed Gain, Current Gain, Offset, Feedback Calibration

• Indicators: Power LED, Run LED, Fault LED, Diagnostic LED array

• I/O Interface: Edge connector (backplane); front 20-pin screw terminal header

3. Mechanical Specifications

• Form Factor: 3U Eurocard

• Dimensions (W×H×D): 100 mm × 160 mm × 45 mm (with heatsink)

• Weight: ~0.68 kg (~1.5 lb)

• Construction: Conformal coated PCB, industrial grade, aluminum heatsink, metal front panel

• Connector: Gold‑finger edge (backplane); front 20‑pin screw terminal header

4. Environmental Ratings

• Operating Temperature: 0 °C to +55 °C

• Storage Temperature: −20 °C to +70 °C

• Humidity: 10%–90% RH, non‑condensing

• Vibration: 10–100 Hz, 0.15 mm amplitude (operational)

• Certifications: UL, CSA, CE

5. Key Features

• Centralized drive control for DC motor speed/torque regulation

• Dual PID loops for precise speed and current control

• Integrated fault detection & diagnostics (overvoltage, overcurrent, overtemperature)

• 8 digital inputs / 6 digital outputs for system interlocking & status

• Non-volatile ROM for firmware storage, battery-backed RAM for parameters

• Compact 3U Eurocard, fits standard CardPAK racks, hot‑swap capable

• Industrial robustness: conformal coating, wide temp range, vibration resistance

6. Compatibility

• Racks: CardPAK 6‑slot, 12‑slot, 18‑slot

• Drives: Reliance FlexPak, MinPak, MaxPak, HR2000 DC drive systems

• Interchangeability: 0-51879-1 / 518791 fully interchangeable