Appliance Parts [Lifetime Warranty] 540-648 uF MFD 110-125 VAC Round Start Capacitor ±20% - Fits OEM Single Phase Motor, Heat Pump - Pack of 2
Two 540-648 uF 110-125 VAC round start capacitors for single phase motors and heat pumps.
BlueStars 540-648 uF 110-125 VAC round start capacitor with technical specification infographic.
Infographic showing dimensions of 540-648 uF 110-125 VAC round start capacitor for motors and heat pumps.
Air conditioner unit illustrating symptoms fixed by a 540-648 uF start capacitor replacement.
Close-up of a 540-648 uF 110-125 VAC round start capacitor for single phase motors and heat pumps.
Close-up of 540-648 uF round start capacitor with 1/4 inch terminals and OEM specifications label.
BlueStars promotional graphic showing a woman relaxing under a functioning HVAC unit for DIY repair solutions.
Two 540-648 uF 110-125 VAC round start capacitors for single phase motors and heat pumps.
BlueStars 540-648 uF 110-125 VAC round start capacitor with technical specification infographic.
Infographic showing dimensions of 540-648 uF 110-125 VAC round start capacitor for motors and heat pumps.
Air conditioner unit illustrating symptoms fixed by a 540-648 uF start capacitor replacement.
Close-up of a 540-648 uF 110-125 VAC round start capacitor for single phase motors and heat pumps.
Close-up of 540-648 uF round start capacitor with 1/4 inch terminals and OEM specifications label.
BlueStars promotional graphic showing a woman relaxing under a functioning HVAC unit for DIY repair solutions.
Lifetime Warranty

[Lifetime Warranty] 540-648 uF MFD 110-125 VAC Round Start Capacitor ±20% - Fits OEM Single Phase Motor, Heat Pump - Pack of 2

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540-648 uF/MFD 110-125 VAC Run Round Start Capacitor

Key Features

  • Capacitance: 540-648 Microfarad
  • Voltage Rating: 110-125 VAC
  • Frequency: 50/60 Hz
  • Operating Temperature: -40°C to +65°C (-40°F to +149°F)
  • Shape: Round
  • Case Material: Moisture-resistant plastic
  • Terminals: 1/4 inch male quick-connect
  • Dimensions (Typical): 1.75 in Diameter x 3.38 in Height
  • Dielectric: Non-polarized aluminum electrolytic

Replaces / Cross-Reference Part Numbers

  • Serves as a universal replacement for any start capacitor with matching capacitance and voltage ratings.
  • Common type designation: CD60
  • Example Part Number: 091A540B125CE7A

Compatibility & Fitment

  • Designed for intermittent duty in AC single-phase motor starting circuits.
  • Used in appliances, HVAC systems, well pumps, air compressors, and other electric motor applications requiring a starting torque boost.
  • Fit is determined by matching electrical specifications and physical dimensions.

When to Replace

  • Motor hums but fails to start or struggles to start.
  • Start-up is slow or delayed.
  • Circuit breaker trips when the motor attempts to start.
  • Capacitor case is visibly swollen, bulging, or leaking.

Installation Tips

  • Disconnect all electrical power to the unit before servicing.
  • Safely discharge the existing capacitor by shorting the terminals with an insulated-handle screwdriver or appropriate discharge tool.
  • Verify that the MFD/uF and VAC ratings of the new capacitor match the specifications of the original part.
  • Note the wire connections before disconnecting the old capacitor to ensure correct polarity-free reattachment.
  • Secure the new capacitor in the mounting bracket to prevent vibration.
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  • Perfect fit

    Perfect fit

    Universal fit with any brands with the same ratings
  • Premium quality

    Premium quality

    This product adopts a high-quality metalized polypropylene film that provides stable and durable performance
  • Saving solution

    Saving solution

    Enjoy the great feeling when your engine is repaired and works properly like before - BlueStars brings DIY solutions to help you deal with any trouble
  • Simple installation

    Simple installation

    Because the capacitor is a relatively simple part, the installation just takes a few minutes and will save you at least a hundred bucks in labor

FAQ

This capacitor is used in single-phase motor applications that require a round start capacitor rated at 540-648 uF (MFD) and 110-125 VAC. It is commonly used in some heat pumps, air conditioning equipment, compressors, blowers, and other motor-driven equipment. Match the microfarad range, voltage rating, shape, and terminal style to your original part before ordering.
Use a replacement with the same capacitance range, 540-648 uF, and do not go below the original voltage rating. This part is rated 110-125 VAC, so it should only be used where that voltage rating matches the original requirement. If your old capacitor is rated higher or lower, verify the equipment specifications before installing.
Typical symptoms include a motor that hums but will not start, hard starting, intermittent startup, overheating during startup, or a compressor or blower that trips overload protection. In some cases the capacitor housing may appear swollen, cracked, or show signs of leakage, though capacitors can also fail without visible damage.
Replacement is usually a moderate repair if the capacitor is easy to access. Typical tools include a screwdriver, needle-nose pliers, and a camera or phone to document wire placement before removal. For many units, the job takes about 15 to 30 minutes. Always disconnect power and safely discharge the old capacitor before handling it.
Verify the old capacitor's label for 540-648 uF and 110-125 VAC, confirm the round body style, and compare the terminal arrangement. It's also smart to inspect the motor, relay, wiring, and terminals for heat damage, corrosion, or loose connections, since a bad start relay or worn motor can damage a replacement capacitor.
Common causes include age, repeated high-load starts, excessive heat, voltage stress, poor ventilation, and underlying motor problems such as dragging bearings or a weak start circuit. In HVAC and heat pump systems, frequent cycling and elevated operating temperatures can shorten capacitor life.
No. A start capacitor is designed to provide extra torque during startup and is usually in the circuit only briefly. A run capacitor stays in the circuit while the motor operates. This part is a round start capacitor, so it should only replace a start capacitor with matching specifications.
The ±20% marking means the actual measured capacitance can vary within 20% of the stated 540-648 uF range and still be within specification. When replacing a failed part, the key is to match the original capacitor's listed capacitance range and voltage rating called for by the equipment manufacturer.