Hello all.
In our village we have a local community owned water distribution system where we use a 12 hp motor with a 12 hp motor starter (star delta) to pump the water.
The star delta starter have the following components:
1) Metasol MC-22b contactor
2) Metasol MT-32 thermal protection relay
The picture is attached herewithin.
Previously due to low power issue on our village the motor was run on a DOL mode that is directly from the middle contactor and both the thermal realy and the primary contactor was byapssed. This way the pump was running fine although the submersible pump wires were a little warm.
Now we bought a 60kva voltage stabilizer and conntected it. Now the motor is also connected as it should be in star delta starter. The motor runs okay for an hour and shuts off automatically. The thermal protection relay MT-32 is so hot to touch .
The phase to phase current are as folows as shown by the ammeter display
RY -----> 22A
YB ------> 22A
BR -----> 22A
Before shutting off itself the ammeter reads around 26A.
Since this is a phase to phase current and the motor only starts in star connection but runs on delta connection later so it means that the line current is root(3) times phase current which is over 40A, the limit of MT32.
Please see the picture of how the starter was connected previously..
In our village we have a local community owned water distribution system where we use a 12 hp motor with a 12 hp motor starter (star delta) to pump the water.
The star delta starter have the following components:
1) Metasol MC-22b contactor
2) Metasol MT-32 thermal protection relay
The picture is attached herewithin.
Previously due to low power issue on our village the motor was run on a DOL mode that is directly from the middle contactor and both the thermal realy and the primary contactor was byapssed. This way the pump was running fine although the submersible pump wires were a little warm.
Now we bought a 60kva voltage stabilizer and conntected it. Now the motor is also connected as it should be in star delta starter. The motor runs okay for an hour and shuts off automatically. The thermal protection relay MT-32 is so hot to touch .
The phase to phase current are as folows as shown by the ammeter display
RY -----> 22A
YB ------> 22A
BR -----> 22A
Before shutting off itself the ammeter reads around 26A.
Since this is a phase to phase current and the motor only starts in star connection but runs on delta connection later so it means that the line current is root(3) times phase current which is over 40A, the limit of MT32.
Please see the picture of how the starter was connected previously..