44 | EngliSH
15,000 operating hours or after five years, whichever
is earlier:
•
General overhaul
If it is used in highly abrasive or corrosive material, the
maintenance intervals should be reduced!
6.3. Maintenance tasks
Monitoring the current consumption and voltage
The current consumption and voltage is to be monitored
periodically during all 3 phases. This remains constant
during normal operation. Slight fluctuations are a result
of the composition of the pumped fluid. The current con-
sumption can assist in early detection and correction of
damage and/ or faulty operation in the impeller/propeller,
bearings and/or the motor. More extensive resulting dam-
age can thus be largely prevented and the risk of a total
failure can be reduced.
Checking the used relays for posistors, sealing room
monitor, etc.
Check the relays used are functioning fault-free. Defective
devices must be immediately replaced, because these
cannot ensure safe operation of the machine. The test
procedure details should be followed closely (in the oper-
ating instructions for each relay).
Checking the insulation resistance
To check the insulation resistance, the power supply ca-
ble must be disconnected. The resistance can then be
measured with an insulation tester (measuring voltage =
1000V DC).
The following values may not be exceeded:
•
The insulation resistance may not be below 20 M
Ω
during initial operation. For all further measurements
the value must be greater than 2 M
Ω
.
•
Insulation resistance too low: Moisture may have
penetrated the cable and/or the motor.
Do not connect the machine, consult manufacturer!
Visual inspection of power supply cables
The power supply line must be examined for bubbles,
cracks, scratches, chafed areas and/or crushed sections.
If damage is found, the power cable must be exchanged
immediately.
The cables may only be changed by the manufactur-
er or an authorized/certified service workshop. The
machine may not be used again until the damage has
been adequately rectified.
Visual examination of the cable holders (carabiners)
and the cable bracing
When the machine is used in basins or pits, the lifting
cables/cable holders (carabiners) and the cable bracing
are subject to constant wear. Regular inspections are nec-
essary in order to prevent the lifting cables/cable holders
(carabiners) and/or cable bracing from wearing out and to
prevent the electricity cable from being damaged.
The lifting cables/cable holders (carabiners) and the
cable bracing are to be immediately replaced if any
signs of wear appear
.
Visual inspection of accessories
Inspect accessories such as suspension units and hoist-
ing gear to check whether they are secured in a stable
manner. Loose and/or defective accessories should be
repaired immediately or replaced.
Fill Level Check in Compression Room/Chamber
Visual control at pump types with oil chamber (models
without cooling jacket or model „U“ with cooling
jacket and open cooling circuit):
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 mechanical seals can be visually
controlled as follows: Put the pump in horizontal position,
so that the screw of the oil chamber is on top (for larg-
er pumps: one of both oil chamber screws). Remove the
screw and take out a small quantity of oil. The oil becomes
greyish white like milk if it contains water. This may be the
result of defective shaft seals. In this case the condition
of the shaft seals should be checked by a HOMA Service
shop. Oil type: degradable HOMA-ATOX. Used oil has to
be disposed according to the existing environmental rules
and regulations.
Visual control at pump types without oil chamber with
cooling jacket and closed (internal) cooling circuit
(“L” Design):
Quantity of Coolant
Please take the precise filling quantity from the spare
parts list or make a request to the manufacturer.
The condition of the mechanical seals can be visually con-
trolled as follows: Set up the pump vertically and unscrew
the ventilation screw 903.02 located above and remove
a small quantity of coolant. If the cooling liquid becomes
grey (original colour: light pink) this may be the result of
defective shaft seals. In this case the condition of the
shaft seals shoul be checked by a HOMA Service shop.
Type: Ravenol (available on request). Used cooling liquid
has to be disposed according to the existing environmen-
tal rules and regulations.
Functional inspection of safety and control devices
Monitoring devices are temperature sensors in the motor,
sealing room monitors, motor protection relays, overvolt-
age relays, etc.
Motor protection and overvoltage relays and other trip el-
ements can generally be triggered manually for test pur-
poses. To inspect the sealing room monitor or the tem-
perature sensor, the machine must be cooled to ambient
temperature and the electrical supply cable of the moni-
toring device in the switch cabinet must be disconnected.
The monitoring device is then tested with an ohmmeter.
The following values should be measured:
Bi-metal sensor:
Value = “0” - throughput
PTC sensor:
A PTC sensor has a cold resistance of be-
tween 20 and 100
Ω
. For 3 sensors in series this would
result in a value of between 60 and 300
Ω
.
