Connecting the sewage pumps
Before the connection, examine the insulation resistance of the motor windings and the monitoring equipment.
Examining the insulation resistance of the motor winding
Examine the insulation resistance with an ohmmeter (measuring voltage = 1000 V). Examine these values:
- At initial commissioning: Make sure that the insulation resistance is no less than 20 MΩ.
- For more measures: Make sure that the value is higher than 2 MΩ.
Examining the temperature sensor of the motor winding
Examine the temperature sensor with an ohmmeter. Examine these values:
- Bimetallic strip: Value = “0” passage
- PTC thermistor sensor: A PTC thermistor sensor has a cold resistance at 20 ... 100 Ω. If there are three sensors in series, the cold resistance is 60 ... 300 Ω.
- If there are four sensors in series, the cold resistance is 80 ... 400 Ω.
Examining the moisture sensor in the motor compartment
Examine the moisture sensor with an ohmmeter. Examine these values:
- This value must approach “infinity”. If the value is low, there is water in the motor compartment.
- The sewage pumps are installed.
- The insulation resistance of the motor windings and the monitoring equipment is checked.
- Connect the sewage pumps to the switchgear based on the wiring diagram.