Run Start Capacitor, Round, 50/7.5 MFD, 440/370

HVAC Service Component – Jard 50/7.5 µF Dual Run Capacitor, 440V Rated

The Mars 12791 Dual Run Capacitor is engineered to support both compressor and fan motor circuits in single-phase HVAC systems. With a capacitance of 50/7.5 microfarads and a 440V rating, it provides stable reactive power in high-demand conditions, making it a reliable component for residential and light commercial air conditioning applications.

This model combines two capacitance values into one round canister to streamline wiring configurations and reduce the need for multiple components in system maintenance or replacement scenarios. It is well-suited for use in split-system condensers and other dual-motor HVAC configurations.

Built for Performance in Field Conditions

The 12791 is constructed using metallized polypropylene film sealed in a non-PCB aluminum case. The hermetically sealed design supports long-term use under varying environmental conditions, including exposure to temperature extremes, moisture, and vibration. Its standard round profile and ¼-inch quick-connect terminals allow for rapid replacement with minimal tools.

• ✅ Dual Motor Configuration – Delivers power to both compressor and fan motors via a single component.
• ✅ 440V Operating Voltage – Suitable for systems with higher voltage tolerances and frequent cycling.
• ✅ Compact Profile – Standard dimensions for compatibility with OEM mounting hardware.
• ✅ Non-PCB Aluminum Housing – Resists corrosion and physical impact in rooftop or pad-mounted units.

Technical Specifications

• Model Number: Mars 12791
• Capacitance: 50/7.5 µF ±6%
• Voltage Rating: 440 VAC
• Frequency: 50/60 Hz
• Form Factor: Round Run Capacitor
• Dielectric: Metallized polypropylene film
• Terminal Type: ¼-inch quick-connect spades

Installation Requirements

Capacitor installation must be performed by trained HVAC personnel familiar with safe discharge procedures and system diagnostics. Ensure voltage is isolated before removing existing components. Always verify capacitance and voltage match OEM specifications to maintain system balance and motor performance.

While the capacitor is designed for straightforward installation, improper wiring or mismatched ratings can result in reduced efficiency or system failure. Standard hand tools and a multimeter are required for service verification and installation validation.

Professional Use Case

The Mars 12791 is widely used in service trucks and mechanical shops for its compatibility with a range of HVAC platforms and its ability to consolidate two capacitive loads into one unit. The aluminum case supports sustained operation in demanding climates, while its standardized footprint ensures fast integration in equipment with limited enclosure space.

Performance Features

• ✅ Supports Dual Circuits – Simplifies service and minimizes component inventory for techs.
• ✅ Heavy-Duty Voltage Rating – 440V capability enhances compatibility with high-efficiency systems.
• ✅ Hermetically Sealed Design – Protects internal film from moisture and contamination.
• ✅ Operational Stability – Maintains precise capacitance values under thermal and electrical stress.