Description

RELIANCE 0-56942-1-CA: DC Bus Capacitor Module for MaxPak Plus / AutoMate Drives

Product Description

The RELIANCE 0-56942-1-CA is a DC bus capacitor module designed for Reliance Electric MaxPak Plus and AutoMate series variable frequency drives (VFDs). This module forms a critical part of the drive’s DC intermediate link, where its primary function is to store and smooth the rectified DC voltage supplied by the front-end diode bridge or controlled rectifier. The RELIANCE 0-56942-1-CA helps maintain a stable DC bus voltage, which is essential for the inverter section to synthesize a clean AC output waveform for the motor. It also supplies the necessary instantaneous energy during motor acceleration and load transients. The reliability and capacitance of the RELIANCE 0-56942-1-CA directly impact the drive’s performance, efficiency, and ability to handle dynamic loads. As a key power component, this module is a vital spare part for maintaining the operational integrity of these legacy

Product Parameters

• Product Type: DC Bus Capacitor Module / Capacitor Bank
• Manufacturer: Reliance Electric (now part of Rockwell Automation)
• Part Number: 0-56942-1-CA
• Compatible Drive Series: MaxPak Plus, AutoMate Drives (specific to certain HP/Frame sizes).
• Capacitance Value: A specific total capacitance (in microfarads, µF) designed for the drive’s DC link.
• Voltage Rating: Rated for the drive’s DC bus voltage (e.g., for a 480V AC input, DC bus is ~650-700V DC).
• Physical Form: An assembly containing multiple aluminum electrolytic capacitors connected in series/parallel, often mounted on a common bracket with balancing resistors.
• Connection: Terminals or bus bars for connecting to the drive’s internal DC power circuit.

Advantages and Features

The RELIANCE 0-56942-1-CA is engineered as an integrated module, ensuring the correct capacitance, voltage rating, and mechanical fit for its designated drive frame. Its key advantage is providing a stable and low-impedance DC power source, which reduces voltage ripple and improves the overall efficiency and performance of the drive. The module is designed with built-in discharge resistors to help safely drain stored energy when the drive is powered off (though waiting the specified time is still mandatory). Using the genuine RELIANCE 0-56942-1-CA guarantees compatibility with the drive’s layout and cooling requirements, and ensures the capacitors are matched for balanced performance and longevity.

Application Cases in Various Fields

This capacitor module is used inside MaxPak Plus and AutoMate drives across various industries. In Industrial Fan and Pump Control for HVAC, water, and wastewater, the RELIANCE 0-56942-1-CA ensures smooth operation of large motors. Within Conveyor and Material Handling systems in manufacturing and mining, it provides the necessary energy buffer for frequent starts and stops. For Machine Tool applications, it helps maintain stable voltage for spindle drives. It is also found in legacy Processing Lines in metals, plastics, and textiles where these drives were commonly applied.

Comparisons with Competing Products

The RELIANCE 0-56942-1-CA is a proprietary Reliance Electric part. Competing drive manufacturers like ABB, Siemens, or Allen-Bradley (Rockwell) use their own capacitor modules in their respective drive series. Compared to sourcing and assembling individual capacitors, this OEM module offers guaranteed performance, correct mechanical fit, and balanced capacitance. Its value lies in being a tested and direct replacement component. Using non-OEM capacitors risks incorrect capacitance, poor thermal management, or physical fit issues, which can lead to drive malfunction, reduced lifespan, or safety hazards.

Selection Suggestions and Precautions

1. Exact Drive Model Match: Capacitor modules are highly specific to drive model, voltage, and HP rating. You must verify that the RELIANCE 0-56942-1-CA is the correct part for your exact MaxPak Plus or AutoMate drive model. Using an incorrect module can damage the drive.
2. High-Voltage Hazard – EXTREME DANGER: DC bus capacitors store a lethal charge even after the drive is disconnected from AC power. You must follow strict lockout/tagout procedures. After disconnecting all power sources, wait the full time specified in the drive manual (often 15-30 minutes or more) for internal discharge. Then, you must verify with a properly rated voltmeter that the DC bus voltage is zero (<10V DC) between all terminals and to ground before touching any internal components.
3. Handling and Inspection: Capacitors are sensitive to shock and aging. Avoid dropping or mechanically stressing the RELIANCE 0-56942-1-CA. Before installation, visually inspect for bulging, leaking, or damaged terminals. Old stock capacitors may have degraded even if unused.
4. Installation and Torque: When connecting the module to the DC bus bars, clean the contact surfaces and use the specified torque for the connection hardware. Over-tightening can damage terminals; under-tightening can cause high-resistance connections that overheat and fail.
5. Disposal: Failed capacitor modules contain hazardous materials and must be disposed of according to local environmental regulations for electronic waste. Do not incinerate or discard with regular trash.

8915-004 DCS
8915-005 DCS
8580-064 PLC
8915-011 DCS
8580-069 CPU
8580-071 PLC
8580-085 PLC
8580-086 PLC