The MARS 19551 is a high-performance potential relay designed for precise motor starting control in HVACR applications, specifically engineered for single-phase capacitor-start motors. This component serves as a direct professional-grade replacement for the 3ARR3MARS551, ensuring seamless integration into existing submersible pump controls and compressor systems. Operating with a continuous voltage rating of 244-270V, the 19551 utilizes electromagnetic induction to drop out the start capacitor once the motor reaches optimal RPM, protecting the start windings from thermal overload. HVAC technicians rely on this specific Mars potential relay for its terminal configuration, which allows for universal positioning and reliable coil voltage response. By maintaining tight tolerances during the pick-up and drop-out cycle, this relay minimizes contact arcing and extends the service life of high-torque motors. Whether you are performing a field repair or a system overhaul, the 19551 provides the electrical reliability required for demanding industrial and residential HVAC motor starter applications. Key Benefits for Contractors Universal Compatibility: Direct cross-reference for the 3ARR3-MARS551, reducing truck stock requirements and ensuring 1:1 field replacement. Precision Calibration: Engineered for 244/270V potential relay specifications to provide accurate contact separation at the precise back-EMF threshold. Industrial Grade Build: Designed to withstand the high-cycle demands of HVACR motor controls in both indoor and outdoor environments. Terminal Flexibility: Standardized terminal layout facilitates faster wiring and integration into potential starting relay circuits. Motor Protection: Prevents premature start winding failure by ensuring the start capacitor is engaged only during the critical motor startup phase. Common Technical Questions Is the MARS 19551 interchangeable with GE 3ARR3 series relays? Yes, the 19551 is the direct equivalent to the 3ARR3MARS551. It follows the same electrical specifications and mounting footprint, making it a drop-in replacement for motors requiring those specific pick-up and drop-out ratings. What is the primary function of this relay in a pump control box? The relay monitors the back-EMF generated by the motor. Once the motor reaches approximately 75% to 80% of its rated speed, the relay opens the normally closed contacts to remove the start capacitor from the circuit. Can this relay be mounted in any orientation? While many potential relays are position-sensitive, the MARS 19551 design allows for versatile mounting; however, it is best practice to follow the manufacturer's orientation markings to ensure maximum contact longevity and reliability. 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.
