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

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