HVAC Motor Not Starting or Running Slowly? Rotom Run Capacitor 36-50-370440 - Restore 50MFD Motor Run Capacitance

A defective motor-run capacitor is one possible cause of compressor, blower motor or condenser-fan motor starting and running problems in HVAC systems. The single-value run capacitor provides continuous phase-shift support to keep the motor running efficiently. When it fails, the motor may hum, struggle to reach operating speed, run intermittently, or overheat.

Common service component in residential and light-commercial HVAC compressors, blower motors and condenser-fan motors.

Part 36-50-370440 is the Rotom specification-based replacement rated at 50MFD and 370/440 VAC that may restore proper motor-run support when testing confirms the original capacitor is defective and no related motor or electrical fault remains.

Is This the Right Part?

Confirm MFD, Voltage, Shape and Dimensions before ordering. This is the correct specification match if ALL of the following are true:

• Your original capacitor is rated exactly 50MFD - capacitance must match exactly
• Your original capacitor is rated 370V or 440V - a 440V replacement may replace a 370V original; the reverse is not permitted
• Your application uses a single-value oval run capacitor - not a dual-run capacitor and not a start capacitor
• Your mounting space accommodates an oval body approximately 2.80in wide, 1.77in deep and 4.33in high

Not sure? Send us your capacitor label specs - we will confirm before you order.

Common Symptoms of a Failed Motor-Run Capacitor

• Compressor, blower or condenser-fan motor hums but fails to start
• Motor starts slowly or struggles to reach full operating speed
• Motor runs hot, trips on thermal overload, or shuts off intermittently
• Capacitor body visibly bulged, leaking, or reads out-of-tolerance on a capacitance meter

If these symptoms match and capacitor testing confirms a defective reading, this is a likely failed component. Similar symptoms may also result from wiring, contactors, relays, motor winding failure, or electrical-supply faults - confirm the capacitor is the root cause before ordering.

Part Details

• Part Number: 36-50-370440
• Brand: Rotom / AllTemp - New
• Type: Oval Single-Value HVAC Motor-Run Capacitor
• Capacitance: 50MFD / 50 uF
• Voltage Rating: 370/440 VAC (dual-voltage)
• Shape: Oval
• Width: 2.80 in
• Depth: 1.77 in
• Height: 4.33 in
• Features: Built-in interrupter, UL and cUL Recognized
• Availability: In Stock
• Compatibility: Specification-based - match capacitance, voltage, shape, and dimensions to original

Also Replaces These Part Numbers

Direct oval replacements (50MFD, 370/440V, oval):
POC50 (Packard), 12049 (MARS), CR50X440 (Supco), 45500HU (DiversiTech) - capacitance, voltage class and oval configuration match; case dimensions may differ slightly by manufacturer. Confirm mounting strap, available height and terminal clearance before ordering.

Electrical equivalent - round shape (confirm mounting fit before ordering):
36-50R3744 (Rotom round, 50MFD, 370/440V) - electrically equivalent; round case is not a mechanical drop-in for an oval mounting bracket. A different mounting strap or bracket may be required.

Installation

Skill Level: Advanced - Qualified HVAC Technician Required. Disconnect and lock out all power before opening the electrical compartment. HVAC capacitor diagnosis and replacement should be completed by a qualified technician. Photograph the original wiring before disconnecting. Connect the replacement to the same terminals and confirm all connections are secure before restoring power and testing motor operation.

Specification Compatibility

This capacitor is compatible with any HVAC motor application that requires an oval single-value run capacitor rated at exactly 50MFD and 370V or 440V, provided the oval body (2.80in wide x 1.77in deep x 4.33in high) fits the existing mounting bracket. Compatibility is determined by electrical specification and physical fit - not by equipment model number. Contact us with your original capacitor label before ordering if you are unsure.

Pro Tip