Resistance Checks - Pentair MYERS MSKHS Serie Installation Et Manuel De L'opérateur

Maintenance
Using an ohmmeter
To be sure wires are not burned off or broken, use an
ohmmeter to perform resistance checks. Set ohmmeter
scale to R X 1 scale and check meter by putting both
meter leads together and adjusting the needle knob until
meter reads zero. If meter cannot be adjusted to zero, the
batteries in meter must be replaced.
NOTICE: Always reset meter to zero [0] when going to a
new scale before making any measurements.
If wire is OK, meter needle will go to near zero and stay
there. If meter needle does not move, the wire has an
open and the wire must be repaired or replaced.

Resistance Checks

1. For single phase (1ø) pumps, attach one meter lead
to the white cord wire of the power cord and the
other meter lead to the black cord wire. This reading
should match the resistance shown in Winding
Resistance Chart, 1ø, 230V.
Model Start Winding
MSKHS50 2.92 Ω
MSKHS100 2.38 Ω
MSKHS150 1.82 Ω
MSKHS200 1.42 Ω
Winding Resistance Chart, 1ø, 230V
For three phase (3ø) pumps, repeat the above
procedure for the black and white wires, the black
and brown wires, and the brown and purple wires.
Each of the three separate readings should read
approximately the same and should match the
resistance shown in Winding Resistance Chart, 3ø.
If no resistance is obtainable for any of the three
phases, either a wire is broken, there is a bad
connection or the winding is defective. Skip Steps 5
and 8 if resistance is OK.
200V
Model
Any one
phase
MSKHS50 21.4 Ω
MSKHS100 17.8 Ω
MSKHS150 14.03 Ω
MSKHS200 2.05 Ω
Winding Resistance Chart, 3ø
2. Remove plug (24) from top of housing (3) and
pour oil into a clean glass container. If oil is clear,
it will indicate motor is not burned and there has
been no water leak into the motor. If oil is black,
it will indicate a burned stator. If oil is cloudy, it
will indicate water in motor oil, so all seals should
be replaced.
Run WInding Total
15.1 Ω 18.02 Ω
12.15 Ω 14.53 Ω
9.12 Ω 10.94 Ω
1.93 Ω 3.35 Ω
230V 460V
Any one Any one
phase phase
21.4 Ω 21.4 Ω
17.8 Ω 17.8 Ω
14.03 Ω 14.03 Ω
10.52 Ω 10.52 Ω
3. After draining oil, remove the hex head cap screws
(18) that attach motor housing (3) to volute (11).
Slide motor housing upward 5 to 6 inches in order
to expose power cord wire connections to motor
(4). Disassemble power cord wire connections from
motor and then disassemble power cord from motor
housing. Using the wire leads from the motor, check
the winding resistance with an ohmmeter.
4. On 1ø units, check capacitor using ohmmeter. With
ohmmeter scale set at R X 1000, attach meter leads
to capacitor. The meter needle should go to zero
and come back slowly. If it does not, the capacitor
should be replaced.
5. Disconnect power cord leads and unscrew the green
ground lead from top of motor.
6. On 3ø units, carefully loosen the power cord
assembly (1) from the motor housing (3). With power
cord loose, remove the four wire nuts (2) and screws
and carefully lift off the motor housing (3) and the
motor assembly.
7. Unscrew wire nuts (2) and remove the power cord
(1) from the pump. Using the spade terminals
coming from the motor (4), check the winding
resistance with an ohmmeter.
8. Attach one meter lead to the motor terminal T1
and the other meter lead to motor terminal T4.
See Winding Resistance Chart for an appropriate
resistance reading. If no resistance is obtainable for
either the start or main winding, either there is a bad
connection or the winding is defective.
9. For 3ø pumps, remove hex head cap screws (18)
from the motor housing (3) and lift up housing until
all wire nut connections (2) are accessible. Unscrew
wire nuts and remove the motor housing (3) from the
pump.
10. Twist the three leads of one end of the power cord
together. Then at the other end, with an ohmmeter,
575V
check any two leads. Also check the third lead with
Any one
either of the first two. If a zero reading is indicated
phase
for any wire, the wire is broken and a new power
33.1 Ω
cord assembly must be installed.
27.8 Ω
11. Set ohmmeter scale pointer to R X 100K scale.
21.9 Ω
Connect one meter lead to one lead of the stator
16.5 Ω
and touch the other meter lead to the motor housing
(3). If the resistance to the ground is less than
500,000 ohms, there is moisture in the winding or
leakage through stator insulation. The stator must be
dried out and then rechecked on the ohmmeter. If
the resistance is still less than 500,000 ohms after
drying, the stator must be replaced. A zero reading
indicates a direct short, and the stator will have to
be replaced.
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