What to look for in a HVAC blower motor?
What to look for in a HVAC blower motor?
In that case, check the windings in the motor before turning the power back on. To check the windings of a motor for an open or a short, you’ll need to measure the ohms. If the unit has a 120V motor, it will most likely have three or four colored wires (black, red, yellow, and blue are common), a white wire, and two brown wires.
How can I tell if my electric motor is shorted?
Use a VOM in ohms setting to check resistance across the capacitor. When the motor is switched “on” the ohms reading should immediately drop to zero then slowly climb again towards infinite resistance. If the meter does not move (no current flows) the capacitor is “open”. If there is very low or zero resistance the capacitor is shorted.
Can a microfarad test a blower motor?
The capacitors on most of residential blower motors are very small, so technicians tend to overlook them. Using a capacitor tester to test the capacitor. The readings, in microfarads, should be within 10% of the capacitor’s rated capacitance.
How many wires does a 120V blower have?
If the unit has a 120V motor, it will most likely have three or four colored wires (black, red, yellow, and blue are common), a white wire, and two brown wires. Do a resistance check between the white wire and each of the colored wires.
What to look for in a 240V blower motor?
Checking 240V motors is slightly different because you will have two hot wires and most will be only single-speed. But you still ohm-out the windings to check for open and shorted windings and check the capacitor the same way. Finally, when doing a routine maintenance call on a unit, always check and clean the motor.
How can I tell if my motor windings are shorted?
When checking the ohms on motor windings, many technicians have difficulty determining an open winding vs. a shorted winding. But it’s really not hard to tell the difference between the two. Read the ohmmeter. It should show a resistance. If it shows a zero reading it probably means the windings are shorted out.
The capacitors on most of residential blower motors are very small, so technicians tend to overlook them. Using a capacitor tester to test the capacitor. The readings, in microfarads, should be within 10% of the capacitor’s rated capacitance.
How can you tell if a motor armature is short?
Depending upon brush size, this may allow access to the commutator without removing the armature from the motor. The first check to see if your armature windings are shorted is the “180° Resistance” test. A volt/ohm meter can be used to check the resistance of the series windings connected between the two commutator bars of each coil.
