Synchrounous motor is three phase motor,but its not self
starting .why?

Answer Posted / saravana babu

let assume the stator field as Ns and Ss..the rotor field as
Nr and Sr..when the given to supply to stator windings,which
cause rmf may occur..assume Ns is repel Nr..as the direction
of rotor is clock wise..(in first half cycle)..in next cycle
Ss is attract Nr(anti clk wise direction)..so the rotor cant
able to rotate in same direction.... so having only low
torque ...so that provides resudual magnetism at
innitialy..(ie dc excitation like alternator)

Is This Answer Correct ?    33 Yes 11 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How to measure current and voltage in an ELV circuit

3761


there is an alternator 480 k.w, 400v,50hz, 4-wire running on load having leakage alternator body earthed current 38 A. is it within acceptable limit? if yes then give reference if no then how to bring within specified limit

1623


What are locations arc protection relay is fixed.

1488


is it possible to turn on the single phase star delta on delay timer using 24 v dc ?

1601


why connecting surge unit in contactor coil

1521






How stabilizer works??

1783


What is an order of a system.

873


What about electrical Units. discrive in detail

1639


What are the material used for resistor?

770


-What should be minimum value of insulation resistance and maximum value of earth resistance at any electrical instillation and what is method of testing the same.

1710


if 2 coil of 1000W connect in series and 200 v is applied across it . then what is the total power of coil when coil have only resistive load .

1668


What are the temperature elements?

854


how withstand of hi-pot test outputs of transformer wire 2.5mm

1628


Dear Respected sir how to test ABB REX521 protection relay by relay tester.

2420


what r substations?what r there work?why voltages r incresed and then reduced during distribution of power

1599