12
English (US)
6.4 Insulation resistance
(lead-to-ground)
To check the insulation resistance (lead-to-
ground) of the motor and leads, a megohmmeter
is required.
To do so, follow these steps:
1. Turn the POWER OFF.
2. Disconnect all leads to the motor.
3. Set the scale selector on the megohmmeter
to R x 100K, touch its leads together, and
adjust the indicator to zero.
4. Touch the leads of the megohmmeter
individually to each of the motor leads and to
ground (i.e. L to ground; N to ground, etc.).
Fig. 12 Insulation resistance measurement
Evaluation
The resistance values for new motors must
exceed 1,000,000 ohms. If they do not, replace
the motor.
6.5 Winding resistance (line-to-line)
To check the winding resistance of the motor
windings, a megohmmeter is required.
To do so, follow these steps:
1. Turn the POWER OFF.
2. Disconnect all leads to the motor.
3. Set the scale selector on the megohmmeter
to R x 1, touch its leads together and adjust
the indicator to zero.
4. Using the following chart for reference, touch
the leads of the megohmmeter to the
appropriate pair of connectors. Check all
pairs that are present and write down and
label (RA
1
, RA
2
, RS) all readings.
5. Compare your readings to the matching
model, phase and voltage on the chart in
section 6.6 Winding resistance chart.
Evaluation
The resistance values must fall within the
tolerances listed in section 6.6 Winding
resistance chart. If they do not, replace the
motor.
TM03 7803 4906
Internal wiring
UP
Terminal plug in stator
Single-phase
RA
1
: Main winding
RA
2
: Main winding
RS: Auxiliary winding