Packard PSMJ378A Start Capacitor

The Packard PSMJ378A is a high-capacitance round motor start capacitor engineered for demanding HVACR applications requiring a 378-455 MFD range at 165 VAC. Designed to provide the necessary torque to initiate compressor or motor rotation against high head pressure, this dry electrolytic capacitor features a rugged phenolic resin housing to withstand harsh mechanical environments. For contractors performing field service, its 1-7/16 inch diameter and 3-3/8 inch height ensure a drop-in fit for standard motor housings. Operating at a frequency of 50/60 Hz, this component is frequently used for single-phase motor starting where high starting torque is critical. This unit effectively replaces BMI 091A378B165AD4A and other common OEM equivalents. When performing a start capacitor replacement, ensure the voltage rating meets or exceeds the original specification to prevent premature dielectric breakdown. This part is a reliable solution for restoring efficiency to refrigeration and AC motors.

• Broad Capacitance Range: Delivers 378-455 microfarads to handle heavy-duty motor startups.
• Standardized Form Factor: Round case design facilitates easy installation in existing capacitor brackets.
• High Temperature Resilience: Engineered to maintain stable performance within industrial operating ranges.
• Quick-Connect Terminals: Features dual 1/4 inch terminals for rapid, secure wiring during field swaps.
• Reliable Discharge: Compatible with 2-watt bleeder resistors to ensure safe handling and protect relay contacts.

Can I use a capacitor with a higher MFD rating than the 378-455 range?
It is critical to match the capacitance range within +/- 10% of the manufacturer’s specification. Over-sizing the MFD can cause excessive current draw, leading to motor winding damage or starting relay failure.

Is the 165V rating compatible with a 120V circuit?
Yes, the voltage rating on a start capacitor indicates the maximum peak voltage it can handle. A 165V rating is suitable for 110/120V applications, providing a robust safety margin against voltage spikes.

When should I replace a start capacitor instead of the potential relay?
The capacitor should be tested for physical bulging, leaking, or out-of-spec MFD readings using a multimeter. If the capacitor is within spec but the motor fails to drop out of the start circuit, the relay is the likely culprit.

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.