Gorman-Rupp Pumps SE1 1/2A3 115V 1P 1483930 and up - Manual (Page 24)

SE SERIES OM−06488
TROUBLESHOOTING PAGE D − 4
Insulation Resistance
To check insulation, zero-balance the ohmmeter
set at the RX100K scale, and test as follows:
a. Disconnect the power cable plug from its re-
ceptacle, or lock out incoming power and
disconnect the power cable leads to the op-
tional manual switch or automatic control
box.
b. Connect one test lead to the power cable
plug grounding prong (or to the green
ground lead), and touch the other test lead
to each of the two power prongs (or power
leads) in turn.
c. The reading obtained will indicate resis-
tance values in both the power cable and the
motor windings. If the resistance reading is
infinity (
1), the insulation is in good condi-
tion. If the reading is between infinity (
1)
and 1 megohm, the insulation is acceptable
but should be rechecked periodically. If the
reading is less than 1 megohm, the insula-
tion should be checked more closely. A
reading of zero indicates that the power
cable or the motor is grounded.
d. To determine whether the power cable or
the motor is grounded, separate the pump
head from the motor housing (see Head
and power Cable Disassembly/Reas-
sembly in MAINTENANCE AND REPAIR
section) and disconnect the Amp-lock plug
and cap. Test the power cable leads and
motor leads separately.
e. Be certain to reconnect the Amp-lock plug
and cap before reassembling the pump
head on the motor housing.