Overview
The Reliance Electric 0-51839-2 is a PCB-based relay card designed for overload and circuit control in Reliance Electric drive and motor control systems. Also known as the IRCC (Integrated Relay Control Card) or S3 Relay Card, this module integrates four relays, transistors, resistors, capacitors, and a single integrated circuit on a professionally laid-out printed circuit board. The board features a conductive backplane “tail” that plugs directly into a Reliance drive rack, eliminating external wiring complexity.
Key Features
- Four relays on board surface for flexible switching and control logic
- Conductive backplane connector for direct rack insertion and secure mounting
- Integrated logic circuitry with transistors, thermistors, resistors, and capacitors
- Front faceplate with reset switch, indicator light labeled “Overload when light is on,” and set screws for handling
- Discontinued design — well-established in legacy Reliance systems; suitable for replacement and repair applications
Technical Specifications
- Component Type: Overload Relay Circuit Board (PCB)
- Relay Count: Four (4) relays
- Connector Type: Conductive backplane tail (rack-mount)
- Integrated Circuits: One (1) IC on board
- Passive Components: Transistors, thermistors, resistors, polyester vinyl or other dielectric capacitors
- Front Controls: Reset switch, dual set screws (top and bottom), overload indicator light
- Grid Reference: Board marked with letter/number grid for component location
- Wiring: Surface wiring in key locations
- Manufacturer Status: Discontinued; original support provided by Reliance Electric
Typical Applications
- Motor and drive overload protection in legacy Reliance control systems
- Relay switching and logic control in automated machinery and industrial equipment
- System upgrades and preventive maintenance replacements
- Equipment retrofits where Reliance drive architecture is retained
- Industrial control panels requiring reliable overload sensing and motor protection
Compatibility & Replacements
Compatible With
- Reliance Electric drive systems and control racks
- Reliance MAXPAK and S3 drive platforms
- Baldor Reliance equipment (historical OEM overlap)
- ABB drive systems (historical product line acquisition)
- Legacy motor control centers and industrial control panels using Reliance components
Replaces / Drop-In Replacement For
- Reliance Electric 0-51839-1 (alternate part designation)
- Earlier overload relay card designs in the same rack form factor
- Note: Always verify mechanical and electrical fit with your specific drive rack before ordering. Consult original equipment documentation for compatibility confirmation.
Works With
- Reliance MAXPAK drive boards and modules
- Standard 24 VDC/120 VAC industrial control logic circuits
- Hardwired relay control networks and logic systems
- Rack-based modular automation platforms using DIN-style or backplane connectors
