Lennox iComfort SL280UH070V36A Manual page 37

Troubleshooting Motor Windings
Ensure that motor windings are not damaged by perform­
ing the following tests:
NOTE - If your ohm meter is not an auto-ranging type, set it
to the highest ohm scale (100k ohms or greater) before
performing tests.
Table 2
Ohm Meter Range
Measurement Range
Scale
in words
two megohm -- two
2M
million ohms
two hundred kilohm
-- two hundred thou­
200k
sand ohms
twenty kilohm --
20k twenty thousand
ohms
two kilohm -- two
2k
thousand ohms
200 two hundred ohm
FIGURE 10
Measure the resistance between each of the three motor
leads (3-pin plug) and the unpainted part of the end shield.
ohms
0-2,000,000
0-200,000
Use an ohmmeter to measure the motor phase-to-phase
0-20,000
resistance by checking these combinations of the the 3-pin
motor plug. For the purpose of this test, start at either end of
the connector as lead 1.
0-2,000
1 - The lead-to-lead resistance across any two leads
0-200
2 - Each lead-to-lead resistance should be the same.
If the measured resistance is greater than 20 ohms, re­
place the motor and control module.
Page 37
TEST A
If the winding resistance to ground is <100k
ohms, replace the motor and control module. If
the resistance to ground is >100k, the motor
windings are fine. Proceed to Test B.
Test A
FIGURE 11
TEST B
should be less than 20 ohms.
Test B
FIGURE 12