MARS 12787 Run Capacitor

The MARS 12787 is a heavy-duty 40/7.5 MFD 440V round dual run capacitor engineered for continuous duty in residential and commercial HVAC systems. This dual run capacitor serves as a critical component for PSC (Permanent Split Capacitor) motors, providing the necessary phase shift to optimize torque and efficiency in both the compressor and the condenser fan motor. Designed as a direct replacement for C44075R, it features a non-PCB oil-filled construction housed in a hermetically sealed aluminum casing to ensure high thermal conductivity and pressure-sensitive internal protection. Operating at 440 VAC, this unit is also compatible with 370 VAC applications, offering superior dielectric strength compared to lower-rated alternatives. For technicians upgrading older systems, the MARS 12787 HVAC capacitor provides reliable capacitance stability under high-ambient-load conditions, effectively managing the inductive load of high-efficiency cooling units while maintaining tight +/-5% tolerances.

• Dual-purpose capacitance: Combined 40 + 7.5 microfarad ratings support both the compressor and fan from a single footprint.
• High-voltage reliability: The 440-volt rating allows for use in various line voltage environments without risk of premature dielectric breakdown.
• Direct cross-compatibility: Specifically designed to replace round run capacitor models including the C44075R and equivalent industry standards.
• Internal safety protection: Equipped with a physical disconnect current interrupter to prevent case rupture at the end of service life.
• Environmental resilience: Operates efficiently within high temperature ranges often found in rooftop and outdoor condenser units.

Can I use a 440V capacitor to replace a 370V unit?
Yes. A 440V rated capacitor can safely replace a 370V unit as it has a higher insulation breakdown point, though you must never swap a lower voltage rating into a higher voltage system.

What are the symptoms of a failing MARS 12787?
Common indicators include the compressor humming without starting, the outdoor fan motor spinning slowly, or visible "mushrooming" of the top physical seal on the aluminum housing.

Is the 12787 compatible with 40/7.5 MFD 370V round capacitors?
This is a direct functional upgrade for 40/7.5 uF 370V units, maintaining the same microfarad values while offering increased voltage overhead.

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.