Answer / jijomon

Single phase motor has pulsating magnetic field and three
phase motor has rotating magnetic field

Answer / ahmed hamdy

single phase motor can't self started so we use another winding only in starting and then this winding disconnected due to motor speed and also connect a capacitor to make phase different to generate rotating magnetic field but in 3 ph this not happened because rotating magnetic field is self generated due to phases different angle which shifted by 120 degree

Answer / venkatakrishnan

3-phase motors are self starting,whereas the single phase
motors are not self starting.

Answer / p. naik

The starting circuit of of a3-phase motor has a contactor
wherein all the 3 phases of the supply are connected to it.
Whereas in 1-phase motors only 2 phases are required & the
third input of the contactor is looped from it's own
output.The main diffrence can be spoted in the power
diagram itself.

what is slip what is the use of slip?

1 Answers  

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What type of motor is used inside computer CPU.

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Dear Sirs, I am a technical persons.In one of our Electrical Sub- Station, We have installed three numbers of 1250KVA ,11KV/0.415KV Transformer to feed the Factory load. We have found some abnormality. In one of our Transformers the leakeage current from transformer body to earth through earth continuity wire is almost 86 Amp but in other transformer it is (5-10)Amp. where the load current on three phase and neutral are respectively 1360Amp,1400Amp,1370 Amp & 176Amp. So please any technical person help me about the reasons of this situation and how I can rectify the fault. Moreover,I have measured the earth resistance of the Earth continuity wire which is less than 1 Ohm. Thanks Tapas Barua

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could mail me the question papers for the test.

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0 Answers  

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From stability point of view,What(higher/lower) should be the value of inertia constant of rotating machines?

1 Answers  

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no of rotrs poles in salient pole synchronous machine

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What are the factors influence the choice of an electrc drive?

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why two over current realy used in vcb.

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all 3 current transformers (C.T) are burnt in a L.T Panel - what are the possible reasons

5 Answers  

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