STAR-DELTA

http://cr4.globalspec.com/thread/26166

Star

What???

The answer is, it is a non-issue. The different windings are intended for different voltages (assuming IEC motors). For example, it is designed to provide 100kW at 400V when connected in Star, or 100kW at 230V when connected in Delta. If you have 230V and connect the motor in Star, it will consume 1/3 of the power, but it will deliver only 1/3 of its rated torque. Speed will remain the same because the number of poles has not changed, therefor the motor kW output capacity is reduced to33kW. If your load has not become 1/3 of what it was, you will stall the motor!

So is it going to save energy? Sure, in the same was as turning it off will, because essentially it will no longer function as a motor.

absolutely agree.....

rated motor in nameplate is based on manufacture standart. commonly, there are 37 kw,45kw,60kw,75kw,90kw,100kw, 110kw,132kw.

first we must know how many Hydraulic Horse Power(HHP) of our load (our friend in mechanical department must be more expert than us). after that we convert to Brake Horse Power (BHP).after we found, for example 97KW.then we find available motor standart KW in market.then we choose 100 KW motor.

second, we must give power for that motor . we must give at least 100 KW from our LV MCC.

third, motor winding have impedance and current that flow in that impedance is constant.(see the picture below). the different is if we wire the motor with different connection (wye or delta). it will make current that flow from our MCC is different too. we need more bigger current from our LV MCC when motor is in delta connection than motor is in wye connection. that caused motor in wye connection less of power.so motor will stall.

Hello guest,

Star connection will consume less power. The current in each winding will be 1/1.732 times in star as compared to delta. So if the required torque is less, running the motor in star will save energy.