Motor Component Checks; Ground Check - A.O. Smith ST1302 Manual

Pump Motors

MOTOR COMPONENT CHECKS

Based on your observations perform the follow-
ing checks to confirm that each component is
functioning properly.

GROUND CHECK

Ground Check — Set ohmmeter to R x 1K.
Attach one probe to ground screw and touch
other probe to all terminals on terminal
board, switch, capacitor and protector. A
reading of less than 10K could indicate a
ground. New motors typically read over one
megohm. Old motors with dust, dirt and
moisture could show resistance to ground
below 10K and still run satisfactorily. A
cleaning may be in order. Readings may vary
from day to day depending upon the humidi-
ty levels. Approximately 25K at 115 volts
will trip a ground fault device. Keep in mind
the ground fault device is seeing the total
leakage of all loads on the circuit. GFI's nor-
mally trip on readings from 4 to 6 milliamps.
If grounded, check all external leads for cuts,
breaks, frayed wires, etc. Replace damaged
leads and recheck for grounds and proper
lead routings. Make sure replaced leads are
not pinched between canopy and end bell.
If ground is in stator, replacement of motor is
recommended.
Level 2
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A.O.Smith