Copeland 940-0001-79 Potential Relay

The Copeland 940-0001-79 Potential Relay is a mission-critical component designed for high-torque motor starting in commercial refrigeration and air conditioning systems. Engineered for precision, this 3ARR3KC3P5 potential relay monitors the back electromotive force (EMF) to efficiently disconnect the start capacitor once the compressor reaches optimal operating speed. This OEM Copeland replacement part ensures consistent compressor start-up and protects expensive windings from prolonged high-amperage draw during the start cycle. With a 400 VAC rating and robust screw-terminal connections, it is built to handle the rigorous duty cycles of industrial environments. Whether you are performing a 940-0001-79 cross-reference repair or a preventative maintenance overhaul, this relay provides the reliability required to maintain system uptime. Its compact, panel-mount design allows for seamless integration into existing control boxes, making it the standard choice for technicians servicing Copeland hermetic and semi-hermetic units.

• High Starting Torque: Optimized for motors requiring significant initial force, ensuring reliable ignition in low-voltage or high-head pressure conditions.
• EMF Sensing Technology: Precision-tuned pick-up and drop-out voltage settings prevent start relay failure and protect the start winding.
• Universal Compatibility: Direct replacement for several 3ARR3 potential relay configurations used in food service and commercial HVACR.
• Industrial Durability: Rated for up to 400 VAC to handle voltage spikes and demanding commercial electrical loads.

How do I confirm the pick-up and drop-out voltage for this relay?
The 940-0001-79 is typically calibrated with a pick-up voltage around 170-180V and a drop-out voltage near 40-90V. Always verify your compressor’s technical data sheet to ensure these specs align with your motor's back EMF profile.

Can I use this relay to replace a 3-wire potential relay?
Yes, this is a standard 5-terminal configuration (typically using pins 1, 2, and 5) that functions as a high-performance HVAC start relay for most capacitor-start, capacitor-run (CSCR) motors.

What are the symptoms of a faulty potential relay?
A failed relay often results in the compressor failing to start (humming), tripping the thermal overload or circuit breaker, or the start capacitor staying in the circuit too long, leading to catastrophic capacitor failure.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.