© 2006 GE ECM by Regal-Beloit
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Indoor Blower Motors
v0.2
Motor Module Tests
These tests are no different than ohming out a 3-phase compressor motor. We want
to confirm that the windings are not shorted to ground and still have equal resistance
phase to phase.
Test A – measure the resistance between each of the 3 motor leads to the
unpainted part of the end shield (Winding to Ground Resistance). Typically a good
motor would read infinite ohms to ground on all leads and a bad motor would read 0
(zero) ohms to ground on any one or all of the leads. However for the purpose of this
test, we will use 100,000 (100K) ohms as the bar, and set the meter to the highest
ohms scale unless it’s auto-ranging. Meg-ohm meters should not be used for this
test.
If the motor fails (the resistance is less than 100k ohms on any one or more leads)
then replace the motor module with the equivalent.
If the motor module passes (the resistance is greater than 100k ohms) then
perform Test B.
Tech Tip
Analog or digital ohm meters will work for this test. Keep in mind that “infinite” ohms
on digital meters may show up in many different ways as such as ( .OL ), ( I∞ ), or
even ( Open ).
Just as a reminder or a way to check a new meter to confirm its readings, when the
leads are not touching, this is infinite ohms. When the leads are touching, this should
be 0 (zero) ohms.
Infinite ohms on an analog meter is basically no
needle movement. If you look closely you can
see the infinity symbol ( ∞ ). When an analog
meter reads 0 (zero) ohms, the needle typically
moves to the opposite end of the scale. Zero
can also be calibrated on most analog meters.
On this meter it’s the screw in the middle under
the words “OHM CIRCUIT”. To calibrate the
meter to 0 (zero) you would touch the two leads
together, and adjust the screw until the needle
is over the 0 (zero).
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