Motor Run Capacitors
Motor run capacitors are designed to stay in the circuit while the motor is running, providing a consistent boost to the motor’s power factor and ensuring smoother, more reliable operation. Ideal for use in appliances, HVAC systems, fans, and pumps, motor-run capacitors help to maintain optimal motor performance by stabilizing voltage fluctuations and reducing energy consumption. Our range of motor-run capacitors is built to meet high industry standards for quality and durability.
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CBB5 Motor Run Capacitors
CBB5 Motor Run Capacitors feature a low-loss, self-healing Metalized Polypropylene Film dielectric system, housed in aluminum can, equipped with 10,000 AFC UL-approved Safety Pressure Interrupter and filled with Non-PCB oil. -
DAO / DAL Motor Run Capacitors
DAO / DAL Motor Run Capacitors feature a low-loss, self-healing Metalized Polypropylene Film dielectric system housed in aluminum can equipped with Safety Pressure Interrupter. -
ADM Motor Run Capacitors
ADM (Metalized Polyester) motor run capacitors features self-healing, metalized dielectric which are smaller and lighter than film-and-foil dielectrics. ADM offers outstanding performance to wide variety of 50/60 Hz. AC or DC appl... -
ADP Motor Run Capacitors
ADP (Metalized Polypropylene) motor run capacitors are compact, self-healing products that find greatest utilization as motor-run capacitors in fractional horsepower electric motors. However, the motor run capacitors may be used i... -
ADPS Motor Run Capacitors
ADPS motor run capacitors are similar to our ADP series of motor / AC capacitors but with the additional protection of Segmented Safety Film that will prevent case rupture in the event of overload, abnormal heat or natural end of ... -
CBB60B Motor Run Capacitors
CBB60B motor run capacitors utilize low-loss metalized polypropylene film for dielectric. The CBB60B motor run capacitors are encapsulated with resin and housed in a self-extinguishing plastic case which allows for superior reliab... -
CBB65 Motor Run Capacitors (Oval-Shaped, Dual Capacitance Value)
CBB65 (V=Oval) Motor Run Capacitors feature a low-loss, self-healing Metalized Polypropylene Film dielectric system, which are oil-filled, and are protected by a 10,000 AFC UL-approved Safety Pressure Interrupter. -
CBB65 Motor Run Capacitors (Oval-Shaped, Single Capacitance Value)
CBB65 (V=Oval) Motor Run Capacitors feature a low-loss, self-healing Metalized Polypropylene Film dielectric system, which are oil-filled, and are protected by a 10,000 AFC UL-approved Safety Pressure Interrupter. -
CBB65 Motor Run Capacitors (Round-Shaped, Dual Capacitance Value)
CBB65 (R=Round) Motor Run Capacitors feature a low-loss, self-healing Metalized Polypropylene Film dielectric system, which are oil-filled, and are protected by a 10,000 AFC UL-approved Safety Pressure Interrupter. -
CBB65 Motor Run Capacitors (Round-Shaped, Single Capacitance Value)
CBB65 (R=Round) Motor Run Capacitors feature a low-loss, self-healing Metalized Polypropylene Film dielectric system, which are oil-filled, and are protected by a 10,000 AFC UL-approved Safety Pressure Interrupter. -
Italfarad/Ducati RPC (Insulated Wire Leads) Capacitors
Completely Dry Construction, no oil to possibly leak, smaller case size than oil-filled capacitors. For use in running single-phase asynchronous motors and in all general A.C. applications at 50/60Hz. -
Italfarad RPN (Quick-Connect Terminals) Capacitors
Completely Dry Construction, no oil to possibly leak, smaller case size than oil-filled capacitors. For use in running single-phase asynchronous motors and in all general A.C. applications at 50/60Hz.
Frequently Asked Questions
What does a motor run capacitor do?
A motor run capacitor stays connected in the motor circuit the entire time the motor is running. It uses a second winding inside the motor to keep single-phase motors turning smoothly and efficiently, which steadies the voltage and reduces energy draw in equipment such as HVAC systems, fans, pumps, and appliances.
What is the difference between a motor run and a motor start capacitor?
A run capacitor is rated for continuous duty and stays energized throughout operation, while a start capacitor only engages briefly to give the motor an initial torque boost and then drops out of the circuit. Run capacitors typically have lower capacitance values (usually under 100 MFD) and are built for constant-duty AC service. Start capacitors have higher capacitance but are rated only for short, intermittent bursts.
What do the MFD and voltage ratings mean, and can I substitute a different value?
MFD (microfarads, µF) is the capacitance and must match the motor’s specification closely — the printed tolerance (usually ±5%) shows the acceptable range. Always match the MFD; using the wrong value can overheat the motor or shorten its life.
The voltage rating (for example, 370V or 440V) is a maximum, so you can safely replace a 370V unit with a 440V one, but never go below the original voltage.
What is a dual run capacitor and what do the terminals mean?
A dual run capacitor combines two capacitors in one housing to serve two motors, often a compressor and a condenser fan in an air conditioner. The terminals are marked C (common), HERM (hermetic compressor), and FAN. The rating is printed as two values, such as 40+5 MFD, where the larger value serves the compressor and the smaller serves the fan.
Should I choose an oil-filled or a dry motor run capacitor?
Oil-filled models (such as Motor Capacitors’ CBB65 round and oval and CBB5 series) offer excellent heat dissipation in demanding, high-temperature applications, and many include a UL-approved safety device that disconnects the capacitor if it fails (a 10,000 AFC safety pressure interrupter).
Dry designs (such as Motor Capacitors’ ADP and ADM series, the ADPS series with added segmented safety film that fails safely open, and the Italfarad RPC/RPN series) are lighter, more compact, and non-toxic, which suits appliances and space-limited installations.
Both are built for continuous 50/60 Hz AC duty.
