Reliance Electric MACS 804.46.20 CWW PLC Drive

The Reliance Electric MACS 804.46.20 CWW is a programmable logic controller and drive module from the MACS (Macro Controller Series) family, also referenced with part numbers 0-55325-37, 0-55325-91, and UM1311.1A. It is designed for DC motor speed and torque control in industrial environments, integrating a PLC core with thyristor power conversion. This unit is typically used in heavy-duty applications such as extruders, cranes, and rolling mills.

Functional Overview

The module combines a 16-bit microprocessor (Intel 80C196) with a 6-pulse fully controlled thyristor bridge. It provides closed-loop control for armature voltage and current, with built-in field regulator (for shunt or separately excited DC motors). Key parameters: motor armature current up to 500A (depending on thyristor module), field current up to 25A. The unit includes a PLC core with 8 digital inputs (24V DC), 6 relay outputs (2A), and 2 analog inputs (±10V, 12-bit).

Part Number Cross Reference

• 0-55325-37: Main control board with firmware version 37.

• 0-55325-91: Power board with gate drive and snubber.

• UM1311.1A: User manual revision and software configuration ID.

Power Specifications

AC input: 3-phase, 230V or 460V AC (field selectable), 50/60 Hz. Armature output: 0–250V DC (230V input) or 0–500V DC (460V input), continuous current 400A, peak 600A for 30s. Field output: 200V DC/10A. The drive includes line fuses and snubber circuits. Cooling: forced air with integral fan (24V DC).

Control Modes

• Speed regulation: ±0.1% of base speed with encoder feedback (optional).

• Torque control: 0–100% rated torque via analog input.

• Constant horsepower (field weakening) up to 2:1 range.

• Current limit (adjustable 50–150%).

PLC Features

The embedded PLC supports ladder logic programming (Reliance AutoMate software). It monitors motor temperature, bus voltage, and external pushbuttons. The controller has a battery-backed real-time clock (3V lithium) and 8KB retentive memory for alarm logging (50 events). Diagnostic LEDs: POWER (green), RUN (green), FAULT (red), and SPEED (yellow).

Communication Ports

• RS-232 (DB9) for programming and remote operator panel.

• RS-485 (Modbus RTU) for networking with other drives (up to 32 nodes).

• Analog output (0–10V) for speed follower.

Environmental and Mechanical

Dimensions (W x H x D): 220 mm x 350 mm x 200 mm. Weight: 8.5 kg. Mounting: vertical on a backplate (IP20 enclosure). Operating temperature: 0 to 50°C; storage: -20 to 70°C. Humidity: 10% to 90% non-condensing. The unit requires 100mm clearance on all sides for airflow.

Safety and Protection

Overcurrent (instantaneous), overtemperature (thermistor input), phase loss, and shorted SCR detection. The drive has a safety input (emergency stop) that removes gate signals within 10 ms. CE and UL 508 listed.

Typical Applications

Used for DC motor retrofits in paper mills, wire drawing machines, and crane hoists. The integrated PLC reduces external component count.

Ordering and Documentation

Reliance Electric part numbers: 804.46.20 CWW, 0-55325-37, 0-55325-91. Manual: MACS 800 Series DC Drive Instruction Manual (UM1311.1A).