Maintenance Work - Homa TP 28 Original Instruction Manual

6.3. Maintenance work

Check of the power input and voltage
The power input and voltage for all three phases must be
checked regularly. In normal operation mode this remains
constant. Slight fluctuations depend on the properties of
the pumped medium. Based on the power input damages
and/or malfunctions of the impeller/propeller, bearing and/
or motor can be detected and repaired early. Major sec-
ondary damages can be prevented with this and the risk
of a total failure can be reduced.
Check of the used switchgears for resistance, sealed
space control etc.
Check the used switchgears for correct function.
Defective devices must be replaced immediately,
since the do not ensure protection of the machinery.
Instructions for the test procedure must be followed
(operating instructions for the respective switchgears).
Testing of insulation resistance
To check the insulation resistance, the power supply cable
must be disconnected. Then, the resistance can be mea-
sured using an insulation tester (measuring DC voltage is
1000 volts).
The following values must be met:
During commissioning, the insulation resistance of 20 MΩ
must be met or exceeded. For additional measurements,
the value must be larger than 2 MΩ. Insulation resistance
is too low: Moisture may have penetrated into the cable
and/or the motor.
Do not connect machine; consult the manufacturer!
Visual inspection of the power supply leads
The power inlet leads must be inspected for bubbles,
cracks, scratches, scour marks and/or crushing zones.
If damages are detected, the damaged power inlet lead
must be replaced immediately.
The leads may only be replaced by the manufacturer
or an authorised/certified service workshop. The ma-
chinery must only be started after appropriate repair
of the damage!
Visual inspection of the cable holders (biners) and the
wiring (traction cable)
If the machine is used in basins/shafts the hoisting wires/
cable holders (biners) and the wiring are subject to con-
stant wear and tear. Regular inspections are required to
prevent a complete wear and tear of the hoisting wires/
cable holders (biners) and/or wiring and a complete dam-
age to the power cable.
The hoisting wires/cable holders (biners) and the wir-
ing must be replaced immediately if there are slight
signs of tear and wear!
Visual inspection of accessories
The accessories, such as for example suspension devic-
es, lifting devices, etc. must be checked for correct fitting.
Loose or defective accessories must be repaired/replaced
immediately.
42 | EngliSH
Visual check for pumps with an oil barrier chamber
Oil Level
Please take the precise filling quantity from the spare
parts list or make a request to the manufacturer.
Oil Condition
The condition of the axial face seals can be checked by
visually inspecting the oil. Place the pump horizontally so
that the oil chamber check screw located on the side of
the motor housing is facing up (for larger pumps; one of
the two oil chamber control screws).
Remove the screw and withdraw a small quantity of oil.
If the oil is milky or cloudy, this indicates a defective shaft
seal. In this case, have the condition of the shaft seals
checked by a HOMA specialist workshop or the factory
Customer Service department. Oil type: biodegradable
HOMA-ATOX. Used oil must be disposed of in accordance
with the valid environmental regulations.
Functional test of safety and monitoring systems.
Monitoring devices, for example, are temperature sensors
in the motor, sealing chamber control, motor protection
relays, monitoring relays, etc. Motor protection relays and
monitoring relays can generally be triggered manually for
testing purposes. To check the sealing chamber control or
the temperature sensor, the machine must be cooled to
ambient temperature and the monitoring device's power
cable in the switch cabinet must be disconnected. The
monitoring device is then checked using an ohmmeter.
The following values should be measured:
Bi-metal sensor: Value is equal to „0" - throughput
Thermistor: A thermistor has a cooling resistance be-
tween 20 and 100 Ω. For 3 sensors in a series, this would
equal a value of 60 - 300Ω.
PT100 sensor: PT100 sensors have a value of 100 Ω at
0°C. This value increases by 0.385 Ω per 1°C between
0°C and 100°C. An ambient temperature of 20°C there-
fore has a value of 107.7 Ω.
Sealing chamber control: The value must increase „in-
finitely". Water may be present in the oil for lower values.
Please refer to the instructions in the optionally available
evaluation relay.
Please contact the manufacturer in the event of larger
deviations!
The procedure for checking the safety and monitoring
equipment for the auxiliary hoisting gear can be found in
the respective operating manual..
General overhaul
During an overhaul, in addition to normal maintenance
work, the motor bearings, shaft seals, O-rings and the
power supply lines are also checked and replaced if nec-
essary. This work may only be performed by the manufac-
turer or an authorised/certified service workshop.
Changing operating fluid
The drained operating fluid must be checked for con-
tamination and water additions. If the operating fluid is
seriously contaminated and more than 1/3 of the fluid is
water, the fluid exchange must be repeated again after 4
weeks.