If you test your fan motor regularly, you can fix it yourself to keep your air conditioning units running cool.
Fan motors are used in a variety of settings, whether to circulate cool air in your home as part of your air conditioning system or for the ventilation of large industrial facilities. Regardless of the size of the component and its specific function, the basic structure of all fan motors is relatively simple, making them easy to repair.
Condenser fan motors are an integral part of refrigerators and freezers, vehicle A/C systems, and all types of HVAC (heating, ventilation and air conditioning) systems. These motors help air-conditioning units work properly by drawing in outside air to be cooled and then blowing hot air back outdoors. There are single-phase condensers, as well as 3-phase fan motors that are usually more efficient.
Other types include permanent split capacitor condenser fan motors, which are specifically designed to dissipate heat from refrigeration equipment and heat pumps, and shaded pole condenser fan motors, single-phase motors that are attached directly to a motor shaft rather than to a spinning belt and therefore operate with higher efficiency and less noise than other motors.
Testing a Fan Motor
A faulty fan motor can cause your air conditioning or cooling system to grind to a halt, so it’s a good idea to test it periodically to stay ahead of any potential issues. With a home, office, or industrial air conditioning system, the best way to test is to set the temperature on the thermostat to cool and walk outside to scope out the AC unit. Take a peek through the vents at the fan and check for the following:
- Will the fan start when the AC is running?
- If the fan is on, are the blades moving slowly? This could be a wiring problem or a damaged fan belt.
- Is something obstructing the blades, like a branch? This can impede the movement of the fan and cause the motor to overheat.
- Is there a rattling noise? This could be the result of a loose or disconnected component.
- A buzzing noise? This might mean the motor itself is powered, but the fan itself isn’t working.
- Are you noticing a burning smell? This might mean the motor is overheated.
After getting a visual on the fan, you can investigate further by turning off the power to the AC unit on your breaker and unscrewing the side panel of the condenser unit. The capacitor provides energy to the fan motor and is easy to identify. Look for the cylinder-like piece with wires attached. If this piece looks swollen, you could have a problem with the capacitor itself. If it looks flat and you are having AC issues, the fan motor could be the culprit.
Check the motor for dirt and grime, as dirt build-up can block the motor hole and cause it to overheat. According to experts, keeping your condenser motor and capacitor clean is an easy way to keep your air conditioning system working efficiently, as well as help avoid costly maintenance issues.
If you’re still not sure of what the problem is, here’s a troubleshooting guide:
Make sure the thermostat is turned on.
Believe it or not, this is often the reason many people falsely think their air conditioner is not working.
Check your circuit breaker.
If the breaker marked “AC” is off, set it to the middle setting and then back to the "on" position.
Investigate your filters.
If you have dirty air filters it can block airflow to the outside unit and cause motor issues.
Check the windings on the fan motor.
To check for a wire short, you have to first measure the ohms, which are the units of electrical resistance between the two conductor points on the motor. The motor should have four wires. Do a resistance check between the white wire to each of the other colored wires using an ohm reader. A reading of zero means the winding is shorted. An infinite reading could mean the motor winding is open. Either of these mean the motor is faulty and should be replaced.
Check the capacitor
As mentioned, the capacitor provides power to the fan motor. A faulty capacitor won’t provide enough power to the blower wheel, fan belt, and other parts of the motor and can therefore cause it to stop working. To test the capacitor, discharge it and use a designated capacitor tester to check what’s known as a microfarad reading. If this reading doesn’t match the listed rating capacity, your capacitor likely needs to be replaced.
Whether it’s powering the air conditioning in the car, at home, or in a large work space, a little preventative maintenance and regular checks will ensure your fan motor is working like it should and your HVAC system is keeping things cool.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.