Answer / k,prakashchandra

As the pf is very low, one of the 3 watt meters will show
negative reading

Answer / natchi

In this test, we use two single phase wattmeters or one 3phase wattmeter, during test one of the 1phase wattmeter reads positive value and other one reads negative value of 3 phase power.

but in usage of 3 phase wattmeter gives directly the whole power of 3 phase supply.

i am using star-delta connections with reverse/forward direction motion of the 75hp induction motor.What should be the ratings of Main,Delta and Star contactors and why?

1 Answers  

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how ups works ? various parts of ups and working principle

1 Answers   Serco,

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What is the fault or needs to be done when frequency in ac drives is not changing?

1 Answers  

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11 KV distribution system where neutral is produced ?

4 Answers   ciss, TATA, Tata Motors,

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Auto transformer starter gives the same effect as star/delta strater if its turn ratio = A 0.5 B 0.67 C o.66 D 0.577

1 Answers  

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if single phase is 230 v three phase is 440 v then what about two phase?and why is it so?

2 Answers   Eicher,

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How to select the gauge of wire for winding of motors? How to select number of turns for winding of three phase induction motor?

1 Answers   npcc,

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resistance of transformer oil=?

1 Answers   HCL,

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How we calculate airgap between phases & terminal box of the transformer? any formulae.

1 Answers  

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why should series motor be started with load and shunt motor should be started without load??????

7 Answers  

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how to calculate the bus-bar size. give formula with description

1 Answers  

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how to select electronic timer(Star-Delta) setting for diff. rating motors

1 Answers   Getrag Ford Transmissions,

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