Gorman-Rupp Pumps SF4A 1488019 and up - Manual (Page 25)

OM-06432 SF SERIES
PAGE D - 4 TROUBLESHOOTING
motor cable green/yellow ground lead. Touch
the other test lead to each of the motor cable
leads in turn. Note the readings.
b. Readings will indicate resistance values in
both the power cable and motor windings.If
resistance reads infinity (
1), insulation is
good. If resistance reads between infinity (
1),
and 1 megohm, insulation is acceptable but
should be rechecked regularly. If resistance
reads less than 1 megohm, insulation should
be checked more closely and frequently.
c. If readings indicate that a ground exists, test
the stator and motor power cable separately.
Replace as required.