Sajjadkhan
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motors of these types make use of star-delta starter with set delay .
consider this when you design your control circuit.
The "other two wires", often these go to an embedded thermistor in the windings. They are normally 500 ohms which goes "high" if the windings over heat. Check them out with a meter. You can buy ready made overload units that take the 500 ohms and open the main contactor if it is exceeded. They also latch, else as the motor cools down the contactor would pull in again. . .
Frank
@Sajjadkhan:
Well the motor will be used on Tubewell to pump water to tank 34 km far. There will be nine Tubewells and nine of these motors.
high guys Its been a situation for me and i need your help to drive 3 Phase,180 HP, Delta connection water pump.
I agree with your point of view.I don't think you know enough about motors to be able to bring this project to a safe and successful conclusion.
I am just concern that running in delta mode may draw more current from the line and over loads the transformer.
As there are 9 motors so there will be 9 step down transformer(1100 -->220v) for each motor but similar line
i didn't say that. I said running motor initally i.e. starting in delta mode is dangerous because the torque is low and if there is a heavy load then motor may not move, in that case there will be no back emf and only thing left is the winding resistance which will heat up and burn.Running in star would cause it to overheat in the long run, as it would be taking under root three times more current per phase compared to delta. I have never seen design that runs motors in star for long.
In a length of 34Km, you are putting away 9 transformers(delta to wye), what about the High tension cables, 9 Transformers, Expensive HT switch gear trolleys, bus couplers, Vacuum Circuit Breakers from companes like Siemens cost in millons. I don't know the project layout, cost feasilbilty for putting away 9 HT transformers. Has this been consulted with any experienced designer? Is your decision, planning has final impact on the approval, modification of this 34km long project? What is your role within all this?
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