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Maintenance – All Motors
GROUND
L2
{
TO
POWER
SUPPLY
BLACK
{
YELLOW
RED
GROUND
POWER MUST
BE SHUT OFF
BLACK
YELLOW
RED
L1
L2 R Y B
L1
TO
PUMP
OHMMETER
SET AT R X 1
GROUND
L2
{
TO
POWER
SUPPLY
BLACK
{
YELLOW
RED
GROUND
POWER MUST
BE SHUT OFF
BLACK
YELLOW
RED
L1
L2 R Y B
L1
TO
PUMP
MEGGER
OR OHMMETER
SET AT R X 100K
CONNECT
THIS LEAD
TO GROUND
ATTACH THIS LEAD
TO WELL CASING OR
DISCHARGE PIPE
FIG. 13 FIG. 14
Table 44 Preliminary Tests - All Sizes Single- and Three-Phase
“TEST” PROCEDURE WHAT IT MEANS
Insulation
Resistance
1. Open master breaker and disconnect all leads from control
box or pressure switch (QD type control, remove lid) to
avoid electric shock hazard and damage to the meter.
2. Use a megohmmeter or set the scale lever to R X 100K
on an Ohmmeter. Zero the meter.
3. Connect one meter lead to any one of the motor leads
and the other lead to the metal drop pipe. If the drop pipe is
plastic, connect the meter lead to ground.
1. If the ohms value is normal (table 45), the motor is
not grounded and the cable insulation is not damaged.
2. If the ohms value is below normal, either the windings
are grounded or the cable insulation is damaged.
Check the cable at the well seal as the insulation is
sometimes damaged by being pinched.
Winding
Resistance
1. Open master breaker and disconnect all leads from control
box or pressure switch (QD type control, remove lid) to
avoid electric shock hazard and damage to the meter.
2. Set the scale lever to R X 1 for values under 10 ohms.
For values over 10 ohms, set the scale lever to R X 10.
“Zero” the Ohmmeter.
3. On 3-wire motors measure the resistance of yellow to black
(Main winding) and yellow to red (Start winding).
On 2-wire motors: measure the resistance from line-to-line.
Three-phase motors: measure the resistance line-to-line
for all three combinations.
1. If all ohms values are normal (tables 13, 22, 24 & 26), the
motor windings are neither shorted nor open, and the
cable colors are correct
2. If any one value is less than normal, the motor
is shorted.
3. If any one ohm value is greater than normal, the
winding or the cable is open, or there is a poor cable
joint or connection.
4. If some ohms values are greater than normal and some
less on single-phase motors, the leads are mixed. See
page 46 to verify cable colors.
44