NOTE
If the insulation resistance values measured on the motor are too low, the winding
insulation is defective. The pump set must not be returned to service in this case.
7.2.1.4 Checking the sensors
CAUTION
Excessive test voltage
Damage to the sensors!
▷
Never test the sensors with voltages exceeding 30 V.
The tests described below measure the resistance at the conductor ends of the
control cable. The actual sensor function is not tested.
Table 16: Resistance measurement
Measurement between terminals ...
Resistance
21 and 22
< 1 Ω
10 and 11
200 Ω - 750 Ω
If the specified tolerances are exceeded, disconnect the power cable at the pump set
and conduct another test inside the motor.
If the tolerances are exceeded again, the motor must be opened and overhauled. The
temperature sensors are fitted in the stator winding and cannot be replaced.
Table 17: Measuring resistance of leakage sensor in the motor
Measurement between terminals ...
Resistance
9 and earth conductor (PE)
> 60 k
Ω
Lower resistance values suggest water ingress into the motor. In this case the motor
must be opened and overhauled.
Table 18: Resistance measurement of the float switch
Measurement between terminals ...
Resistance
3 and 4
< 1 Ω
If the readings suggest an open switch, check for mechanical seal leakage.
Table 19: Resistance measurement of the bearing temperature sensor
Measurement between terminals ...
Resistance
15 and 16
100 Ω - 120 Ω
7.2.1.5 Checking the mechanical seal leakage (only pump sets with reinforced
bearings)
WARNING
Fluids posing a health hazard
Hazardous to persons and the environment!
▷
Collect and properly dispose of flushing liquid and any fluid residues.
▷
Wear safety clothing and a protective mask, if required.
▷
Observe all legal regulations on the disposal of fluids posing a health hazard.
NOTE
Slight wear of the mechanical seal is unavoidable. This will be aggravated by abrasive
substances contained in the fluid handled.
✓
The pump set has been placed in vertical position.
1. Place a suitable container under screwed plug 903.34.
2. Remove screwed plug 903.34 and joint ring 411.34.
Temperature sensors in
the motor winding
Leckage sensor in the
motor
Float switch (mechanical
seal leakage)
(only pump sets with
Bearing temperature
sensor
7 Servicing/Maintenance
Amarex KRT
39 of 74
Goodnal STP ST041 Sewage Delivery (Amarex KRT Submersible Motor Pump) Vendor Manual
Q-Pulse Id VM362
Active 29/10/2013
Page 41 of 96