MARS 12838 Run Capacitor

The MARS 12838 Run Capacitor is a high-performance 50/5 MFD 370V dual run capacitor designed for continuous duty in residential and commercial HVACR systems. As a veteran-grade oval motor run capacitor, it provides the precise phase shift required to maintain an even magnetic field in single-phase motors, protecting your hardware from overheating and excessive noise. This dual-rated component serves both the compressor and the fan motor, featuring a 50 microfarad rating for the hermetic terminal and 5 microfarads for the fan.

Constructed with non-PCB dielectric fluid and a physical interrupter, the MARS 12838 meets EIA-456-A standards for 60,000 hours of operating life. This HVAC replacement capacitor is a direct cross-reference for the obsolete Mars 12138 and is suitable for any application requiring 370 VAC or lower. The 50+5 uF oval capacitor design ensures a compact footprint for tight control boxes while providing the reliable torque necessary for peak "start and run" efficiency in air conditioners and heat pumps.

• Dual-Action Support: Manages both the compressor (50 MFD) and fan motor (5 MFD) from a single dual run capacitor housing.
• Industrial Specifications: Rated for 370 VAC at 50/60 Hz with a tolerance of +/- 5% to meet stringent OEM capacitor specifications.
• Enhanced Safety: Built with a pressure-sensitive interrupter to safely remove the capacitor from the circuit at the end of its functional life.
• Broad Compatibility: Fits various central air conditioning units and heat pumps requiring oval 50/5 microfarad capacitance.

Can I use a 440V capacitor to replace this 370V unit?

Yes. You can always increase the voltage rating (e.g., using a 440V in place of a 370V) as it indicates the peak voltage the capacitor can withstand. However, you must never use a lower voltage rating than the original equipment specifies.

What happens if the capacitance (MFD) is not matched exactly?

Deviating from the 50/5 MFD rating can lead to improper motor torque, increased energy consumption, and premature motor failure. Always match the microfarad rating exactly.

How do I identify the terminals on this oval capacitor?

The terminals are typically marked 'C' for Common, 'HERM' for the compressor (50 MFD), and 'FAN' for the fan motor (5 MFD). Ensure power is disconnected and the old capacitor is discharged before installation.

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.