Answer / pratheesh

In previous days, efficient speed control of AC motor were
very difficuil. And also to run the AC motors at very low
speed also very difficuilt. Thats y in those days we used
DC motors expecially in traction system.
But with the arrival of VFDs for AC motors, we can use AC
motors also for low speed application efficiently.
And also the maintenence of AC motors are very very less as
compared to DC motors which has commutators and bruches.

Answer / vinod

because of the high torqure requirement.
now a days the motors are converted to ac

Answer / ganesan

it might use for our convenient of speed control we are
using variable frequency drive.the AC drive when compared
to DC drive so many advantages like better speed
control,less cost,accuracy,simple contruction etc.

Answer / vinay

DC DRIVE AND MOTOR NEEDS PERIODIC MAINTENANCE,AS IN AC
DRIVES AND MOTOR IT IS LESS.ie TO AVOID THE DOWN TIME OF
THE SYSTEM ALSO AC DRIVES AND MOTORS ARE USED

How phase displacement change in the over current relay coils.

0 Answers  

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At site, we have 30Kw motor (3 phase, 400V,50Hz) and FLC 54A as per the nameplate. At the time of starting it draws 840A instead of 390A (7.2%). As per the data sheet also its 390A starting current. it thru a dol starter from the MCC. can anyone tell what is the problem in the motor

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DEAR ALL I have motors ( 10 units )each one is 90kw 380V 50 HZ 1000rpm but new local pwer is 220v 60 hz requierd rpm should be 1000 pleas what the beast solution is used frequncy converter or rewinding all motos or chang all motors thanks

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