1. General Information

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

• Part Number: 0‑51445‑A (051445‑A, 0‑51445A)

• Product Type: Emitter Follower / Gate Driver Amplifier Board

• Application: Reliance S3 / ImPak Plus / VS series DC variable speed drives

• Function: Buffers, amplifies and isolates low‑level control signals; provides regulated SCR gate drive pulses; stabilizes drive operation and improves noise immunity

• Status: Obsolete (OEM discontinued); available as used / refurbished

• Warranty: 6–12 months (refurbished units)

2. Electrical Specifications

• Input Control Voltage: ±15 VDC (from power supply board 0‑51444)

• Input Signal: Low‑level analog/logic commands from main control board (0‑51381 series)

• Output Drive: 6‑channel isolated SCR gate firing pulses (compatible with 3‑phase bridge)

• Isolation Voltage: 2500 VAC (control‑to‑power isolation)

• Onboard Adjustments: 5× multi‑turn trim potentiometers (bias/gain/balance)

• Onboard Protection:

  • Fast‑acting fuses

  • TVS diodes & metal‑oxide varistors (transient suppression)

  • Overcurrent limiting & short‑circuit protection

• Signal Bandwidth: DC to 10 kHz

• Max Output Current: 500 mA per channel

• Regulation Accuracy: ±1.5% at full load

3. Physical & Mechanical

• Dimensions (L × W × H): 220 × 35 × 25 mm (8.7 × 1.4 × 1.0 in)

• Weight: Approx. 0.2 kg (0.44 lbs)

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

• Key Components:

  • 5× metal multi‑turn variable resistors

  • High‑speed power transistors

  • Opto‑isolators & pulse transformers

  • Diodes, capacitors, power resistors

• Connection: 26‑pin edge connector + flying leads to SCR stack

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 Power Supply Board: 0‑51444

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

• Drive Models: S3, ImPak Plus, VS series DC drives

6. Installation & Adjustment Notes

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

2. Mounting: Insert board into designated drive slot; secure flying leads to SCR gate terminals.

3. Voltage Check: Verify ±15 VDC control supply is within ±5% tolerance.

4. Adjustment: Use 5 trim pots to calibrate bias, gain and phase balance for optimal SCR firing.

5. Phasing Check: Confirm pulse transformer wiring phasing before energizing drive.

6. Test: After installation, test SCR firing and motor rotation direction.