Reassembly - Pentair MYERS MSK75 Manual Del Operador E Instalación

Maintenance
7. If the wiring is grounded and there is no apparent
moisture in the oil (see step 2), the stator must be
checked with a high pot tester.
Shock Hazard. Due to the high voltage,
use extreme care when using the high pot tester.
A dangerous shock can be avoided with careful
handling of the test probes.
Using a voltage of 1500 volts for 115 volt motors
and 2000 volts for 230 volt motors, touch one
probe to the white lead and the other probe to the
stator laminations for only one second. Buzzing
will indicate arcing is occurring at a breakdown of
insulation or a small amount of moisture is present.
The stator will then have to be dried out or replaced.
The high pot test is very destructive. So, each time
the same stator is checked, the voltage should be
lowered about 250 volts. If not, you may cause the
stator to short by breaking down the insulation.
8. Repeat step 4, this time attaching the meter leads
to the stator wires. If a zero reading is obtained, the
winding is defective and the stator must be replaced.
9. Remove the impeller screw and impeller washer,
then unscrew the impeller (10). Hold the rotor/
shaft assembly with a screwdriver and carefully tap
impeller with a plastic or rubber hammer.
10. Remove the flat head machine screw from seal plate
(9). Remove clamp ring (8) and motor housing (4) off
the seal plate (9).
11. Remove the four hex head stator bolts and lift the
stator from the seal plate (9). A screwdriver can be
inserted under the stator shell in order to remove
the stator.
12. Bump the end of the shaft with a plastic hammer.
This will push the rotating half of the mechanical
seal (14) from the shaft and also push the lower
bearing from the seal plate (9). Now remove the
shaft, rotor and bearing assembly from the seal
plate (9).
13. If water is found in the oil, both the rotating and
stationary halves of the mechanical seal (14) must be
replaced. Remove the stationary seal half by inserting
a screwdriver into seal plate (9) from the top and
tapping lightly with a hammer.
14. 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.

Reassembly

1. Thoroughly clean the seal (14) and bearing pockets
in the volute. All sand and dirt must be removed.
2. If the stationary seal half was removed, coat the
replacement stationary seal half with O-ring lube
and use a plastic pusher to press it into the motor
housing (4). Make sure the rubber ring goes in first.
Do not use any sharp objects that may damage
the seal.
3. When installing a replacement bearing, press only
on the inner face and make sure the bearing is flush
against the snap ring. If a press is not available, the
bearing can be tapped onto the shaft using a sleeve
that bears only on the inner face. Pressing on the
outer face will ruin the bearing.
NOTICE: Never pound on the outer face of the
bearing as this will cause bearing damage.
4. Push the shaft, rotor and ball bearing assembly
into the seal plate (9), being careful not to chip the
ceramic of the stationary seal half.
5. Replace the motor (5) if it is visibly burned or if the
ground resistance test or the winding resistance test
has failed. Note that the replacement stator must be
of the same manufacture as the existing rotor or vice
versa. Replace the four stator bolts.
6. Coat the rubber ring on the rotating seal half with
O-ring lube and press the seal onto the shaft with the
rubber ring facing the impeller (10).
NOTICE: Mixing old and new seal parts will cause
immediate seal failure. When replacing seal, replace
both the rotational and the stationary seal halves.
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