Grundfos KPL, Инструкция по установке и эксплуатации

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17
English (US)
14. Fault finding
Fault Cause Remedy
1. Pump does not start. a) A fault signal is indicated on
the control panel.
• If the bearing temperature is high, take the pump to the workshop
for repair.
• If the stator temperature is high, check that the water is able to
move around the stator housing without any objections, and that
the propeller/impeller rotates easily.
• If there is a fault in the thermal protectors, contact an authorized
electrician. Check that the overload protection is reset.
b) The pump cannot be started
manually.
Check the following and, if necessary, take corrective action:
• are the control voltage and control fuse OK?
• are all connections securely tightened?
• are the relay and contactor coils functioning correctly?
c) A fault signal is indicated on
the starter.
Check the following and, if necessary, take corrective action:
• is the supply voltage correct on all phases?
• is the main power switch is on and are fuses intact?
• has the overload protection been reset?
• is there damage of the motor cable?
2. Pump starts, but the motor
protection stops it after a
few seconds.
a) The motor protection is set
too low. (Check motor data
in nameplate). Adjust the settings of the motor protection.
b) It is difficult to rotate the
propeller/impeller by hand.
Clean the propeller/impeller of fibers and rags.
Clean out the pit.
c) The voltage on all three
phases, are correct.
Contact an authorized electrician.
d) The phase currents are
unbalanced or too high.
Contact an authorized electrician.
e) The insulation between the
phases and between
phases and ground (earth)
in the stator is defective.
Use an insulation resistance tester set to 1000 VDC and check that
the insulation between phases and between phases and ground
(earth complies with the correct levels for the type of motor.
Contact an authorized electrician.
f) The density of the pumped
liquid is too high. (Max.
density: 68.8 lbs/ft
3
).
Dilute the liquid.
g) Fault in motor protection
devices.
Replace the defective motor protection devices.
3. The pump does not stop. a) The pump is not able to
empty the pit to stop level.
Check the following and, if necessary, take corrective action:
• is the pipe connection tight?
• is the propeller/impeller clogged?
• are the valves open?
b) Fault in the level-sensing
equipment.
Clean the stop sensor.
Check the contactor and holding circuit.
Replace defective components.
c) Stop level is set too low. Increase the stop level.
4. The pump starts, stops
and starts in rapid
sequence.
a) The pump starts due to
backflow which fills the pit
to the start level again.
Check the following and, if necessary, take corrective action:
• is the distance between the start and stop level too small?
• are the valves, if any, OK?
• does the non-return valve function correctly?
b) The holding function of
contactors fails.
Check the following and, if necessary, take corrective action:
• is the contactor connection OK?
• is the voltage in the holding circuit OK in relation to the rated
voltage on the coil?