MARS 12749 Run Capacitor

The MARS 12749 Run Capacitor is a high-performance 45/7.5 MFD 370 VAC round dual run capacitor engineered for heavy-duty HVACR applications. Designed to support both the compressor and the condenser fan motor, this dual motor run capacitor provides the necessary phase shift to maintain optimal torque and efficiency in split-phase motors. Built with metallized polypropylene film and housed in a rugged, non-PCB aluminum canister, it is an essential component for residential and light commercial air conditioning units. The MARS model 12749 features a patented pressure-sensitive interrupter (PSI) that safely disconnects the capacitor in the event of internal pressure buildup, preventing case rupture. This HVAC replacement capacitor is rated for 50/60 Hz and operates reliably in extreme temperatures ranging from -40°C to +70°C. With standard 1/4-inch male quick-connect terminals and a compact round profile, it ensures a straightforward drop-in replacement for failed OEM units, including those from GE, Genteq, and Supco.

• Dual-Circuit Functionality: Manages both the 45 MFD compressor and 7.5 MFD fan motor requirements in a single, space-saving round housing.
• Robust Safety Features: Equipped with an internal pressure-sensitive interrupter (PSI) for maximum protection during electrical faults.
• Tested Durability: Rated for approximately 60,000 hours of operational life, meeting the stringent EIA-456A industry standards.
• Wide Compatibility: Directly replaces Marshalling numbers 12749 and 12249, as well as several obsolete GE and Genteq industrial parts.
• Environmental Resilience: Encased in a corrosion-resistant aluminum shell designed to withstand high-vibration outdoor environments.

Can I use a 370V capacitor if my original was 440V?
No. You should never replace a 440V capacitor with a 370V unit. However, a 440V capacitor can safely replace a 370V unit, provided the MFD ratings match exactly.

What does the +/- 6% tolerance mean for this part?
This indicates the allowable variance in capacitance. The MARS 12749 is precision-engineered to stay within 6% of its 45/7.5 MFD rating to ensure the motor operates within its designed performance curve.

How do I identify the terminals for installation?
The terminals are clearly marked: 'Herm' for the compressor (45 MFD), 'Fan' for the condenser fan (7.5 MFD), and 'C' for the common line.

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.