Model Definition

• 0-58703-5: Full part number

  • Leading 0: Factory-original, unmodified unit

  • 58703-5: Base model (Drive Regulator Board for MaxPak III DC Drives)

• Series: MaxPak III (DC Drives) / Reliance Drive Boards

• Variant: Standard industrial revision (no conformal coating)

• Alternate P/N: 0587035, 58703-5C

Technical Specifications

General

• Brand: RELIANCE (Reliance Electric / Baldor Reliance / ABB)

• Type: Drive Regulator Board (DC Drive Control Card)

• Form Factor: Square PCB, rack-mounted (MaxPak III drive chassis)

• Dimensions: ~12 in × 12 in (305 mm × 305 mm)

• Weight: ~1.8 kg (4.0 lbs)

• Operating Temperature: 0°C to +60°C (standard)

• Storage Temperature: -40°C to +85°C

• Humidity: 5%–95% non-condensing

• Key Components: 6 transformers, 40+ integrated circuits, power regulation & feedback control circuits

• Certifications: CE, UL listed

• Manual: Available via Reliance/Baldor technical archives (MaxPak III Drive Manual)

Electrical & Control

• Input Power: From MaxPak III drive’s internal PSU (isolated AC/DC)

• Control Signals: Speed reference, current feedback, voltage feedback, enable/disable

• Regulation Modes: Closed-loop speed, current, and armature voltage control

• Drive Compatibility: MaxPak III three-phase DC regenerative VS drives (230V–600V DC output)

• Motor Compatibility: High-power DC motors (series/separately excited)

• Protection Logic: Overcurrent, overvoltage, overspeed, short-circuit, thermal overload

Interface & Communication Configuration

Physical Interfaces

• PCB Edge Connectors: Multi-pin (power, control, feedback, I/O) for MaxPak III chassis backplane

• Terminal Blocks: Field wiring for speed reference (0–10V/4–20mA), enable, and fault signals

• Front Panel (Drive Chassis): LED indicators for POWER, RUN, FAULT, OVERCURRENT

Communication

• Bus Interface: Proprietary MaxPak III drive internal bus (no external network)

• Signal Format: Analog (speed reference/feedback) + digital (enable/fault logic)

• Feedback Integration: Accepts armature voltage, current transformer, and tachometer encoder signals

Core Functions

1. Closed-Loop Speed Regulation: Maintains precise DC motor speed via tachometer/encoder feedback.

2. Current & Voltage Control: Regulates armature current and voltage for stable torque and power output.

3. Regenerative Braking Management: Controls energy recovery during deceleration (MaxPak III regenerative drives).

4. Fault Detection & Protection: Monitors overcurrent, overvoltage, overspeed, and thermal conditions; triggers drive shutdown on faults.

5. Drive System Coordination: Synchronizes with MaxPak III power stage for consistent DC output to motors.

6. Parameter Configuration: Onboard trim pots for speed loop gain, current limit, and voltage calibration.

Application Scenarios

• Legacy MaxPak III DC Drive Retrofits: Direct replacement for failed regulator boards in industrial DC drive systems.

• Heavy-Duty Motion Control: Steel mills, paper mills, cranes, hoists, and extruders using high-power DC motors.

• Regenerative Drive Systems: Applications requiring energy recovery during motor deceleration (e.g., conveyors, winders).

• Process Control: Industrial lines with precise speed/torque regulation (e.g., metal processing, material handling).

Usage & Maintenance Instructions

Installation

1. Power Off: De-energize the MaxPak III drive and connected DC motor before removal/installation.

2. Remove Old Board: Disconnect edge connectors and terminal wires; release mounting screws.

3. Insert New Board: Align with chassis guides; seat edge connectors firmly; tighten mounting screws (torque 1.0–1.2 N·m).

4. Reconnect Wiring: Restore terminal block connections (speed reference, enable, fault signals).