⇨
The insulation resistance of the core ends against earth must not be lower than
1 M
Ω.
If the resistance measured is lower, power cable and motor resistance must be
measured separately. Disconnect the power cable from the motor for this
purpose.
NOTE
If the insulation resistance for one of the power cables is below 1 MΩ, the cable is
defective and must be replaced.
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 core ends of the control
cable. The actual sensor function is not tested.
Table 16: Resistance measurement
Measure 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 repeat the check inside the motor.
If the tolerances are exceeded here, too, the motor section has to be opened and
overhauled. The temperature sensors are fitted in the stator winding and cannot be
replaced.
Table 17: Resistance of leakage sensor in the motor
Measure 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
Measure 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
Measure between terminals ...
Resistance
15 and 16
100 Ω - 120 Ω
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
41 of 78
Summary of Contents for Amarex KRT
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