Ground Check - Pentair Myers MES50 Installation Et Manuel De L'opérateur

Maintenance
Checking motor operation
If the unit is being operated by float switch, unplug
the pump from the piggyback receptacle and plug the
pump directly into the power source. Motor should start
and run smoothly. If motor does not start each time it is
plugged directly into the receptacle and does not start
each time when plugged into the piggyback switch with
the float raised, replace the complete piggyback switch
assembly and retest with new assembly.
If motor does not run when tested with functional switch,
the capacitor and/or stator must be checked.
Checking motor stator
1. Remove plug (6) from top of housing (2) 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.
2. After draining oil, carefully loosen the power cord
assembly (22) from the motor housing (2). With
power cord loose, remove the screws (4) and
carefully lift off the motor housing (2) exposing the
motor assembly.
3. On single phase (1ø) units, check capacitor (28)
using ohmmeter. With ohmmeter scale set at
R x 1000, attach meter leads to capacitor leads.
The meter needle should go to zero and come
back slowly. If it does not, the capacitor should
be replaced.
4. To check motor stator, remove power cord leads
from terminals on top of motor (1ø) or remove
splice connectors (3ø). If stator is visibly burned,
motor assembly must be replaced. If stator is not
burned but the oil shows signs of water, stator can be
checked with the ohmmeter to see if it can be used.

Ground check

Set ohmmeter scale to R X 100K scale. Connect one
meter lead to one blade terminal of stator and touch
other meter lead to motor housing (2). If the resistance
to the ground is less than 500,000 ohms, stator must be
dried out before retesting. To dry out, place pump in 220
degree oven for four hours. Recheck after motor cools.
If motor is thoroughly dry, needle of ohmmeter will not
move on the ground check. This indicates a reading of
50 megohms or higher. When making the ground check,
if the needle goes to zero, the motor has a wire touching
the stator shell at some place and the stator will have to
be replaced. Repeat for each leg or wire lead.
NOTICE: If motor shows a satisfactory ground check then
the winding resistance must be checked.
Winding resistance test
1. Use ohmmeter with scale set to R X 1 scale. On this
scale, meter reads directly in ohms. Recheck to zero
[0] before making a reading on the winding.
NOTICE: If water is found in motor, seal should
be replaced.
2. For single phase pumps, connect one meter lead to
the white wire terminal and the other meter lead to
the black wire terminal. This reading is for the main
winding. If the readings obtained do not agree with
those given below, the stator is defective and the
motor assembly must be replaced.
Reconnect the wires as they were removed.
Replacing seal
A milky appearance to the oil collected earlier indicates
that water has entered through worn or damaged seals
or O-rings. In this case, the mechanical seal (14) and
the O-ring (19) will have to be replaced. The seal (14)
consists of a ceramic stationary seat and a carbon
rotating ring. To check seal:
1. Remove bottom plate (12) and impeller (11).
2. Remove the rotating carbon ring and stainless
steel spring.
3. Remove the hex head stator bolts and lift the stator
(3). A screwdriver can be inserted under the stator
shell in order to remove the stator.
4. Tap the end of the shaft with a plastic or rubber
hammer. This will push the rotating half of the
mechanical seal from the shaft and also push the
lower bearing from the seal plate. Now remove
the shaft, rotor, and bearing assembly from the
seal plate.
5. Turn the bearing by hand: if it feels rough when
turned or looks rusted, it should be replaced. Use a
bearing puller to remove the bearing.
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