Problems with motors may actually be within the start capacitor rather than the fan motor itself. Many motors use start capacitors to regulate the electrical components of the motor during the start process. Testing the start capacitor before you throw away the motor saves the expense of purchasing another motor as compared to the cost of replacing the start capacitor. Replacing the capacitor usually doesn't require calling a professional electrician.
Things You'll Need
- Phillips screwdriver
- Slotted screwdriver
- Analog volt meter
- Safety glasses
Disconnect the wires that supply power to the motor with appropriate screwdrivers. Let the wires that run from the capacitor to the motor connected for the time being.
Switch the analog volt meter from ohms to volts. Create a parallel circuit by placing the leads on the meter onto the wires of the capacitor. Hold these leads until the reading from the voltage meter is zero.
Disconnect the wires that run from the capacitor to the motor. Switch the volt meter to the ohm setting. Place the leads of the ohm meter on the wires that run from the capacitor to the motor. Count to three while the leads on the meter charge the capacitor. Reverse the leads on the capacitor. Look for movement of the needle on the meter toward infinite ohms. If the meter doesn't move toward infinite ohms, the capacitor is bad.
Look for movement of the needle on the meter toward infinite ohms. Repeat this step three times. Replace the capacitor if this step fails at any time.
Tips & Warnings
- Safety glasses should be free of dust and debris to protect your eyes during the testing and changing of the capacitor while at the same time preventing vision from becoming obstructed.
- Observe all electrical codes when working with any electrical wiring.
- Shorting the capacitor across the terminals could cause an explosion.
How to Check an Electrical Capacitor
Electrical capacitors when used in alternating current (AC) circuits can be likened to a battery. The capacitor stores an electrical charge to...
How to Replace a Ceiling Fan Capacitor
The ceiling fan capacitor is an important part of the electric circuit that starts the fan motor and lets it rotate at...
My Ceiling Fan Hums but Doesn't Work
If your ceiling fan hums without turning, it may have a mechanical problem, bad connection or switch or a burnt-out capacitor.
How to Check an Air Conditioner Capacitor with a Multimeter
Capacitors are electrical devices, used in the compressors and fan motors of air conditioners, that store an electric charge. There are two...
How to Test an RV Air Conditioner Capacitor
RV air conditioners have two capacitors: a motor run capacitor and a motor start capacitor. A motor run capacitor is used in...
How to Wire Up a Start Capacitor
Large electric motors with a high starting torque, like an air conditioner's compressor motor, often use a start capacitor kit. A start...
How to Wire a Compressor, Fan Motor & Capacitor
The compressor, fan motor and capacitor work together in an air-conditioning system's condensing unit. The wires feeding high-voltage electricity to the condensing...
Can a Home Fan Capacitor Overheating Cause a Fire?
Electricity produces heat, and heat can sometimes cause fires. Fans use large capacitors to help regulate their motors. Because capacitors store electricity,...
The Different Types of Capacitors for Fan Motors
A capacitor is a component whose main function is to store electricity or electrical energy. It also functions as a filter which...
Can You Replace a Ceiling Fan Motor?
If you enjoy your home's ceiling fans, because they circulate air around the rooms and enable you to reduce the cost of...