Answer / rajesh

AC drives are having very good speed control and very
effcient

Answer / abhijit

yes ac drive also its power consumtion and maintance codt
is less then dc drive and also its cost is less

Answer / x man

AC DRIVE IS THE BEST OPTION because when compared to DC
motor AC motor are more prefered due their capital cost and
running cost.
they are low maintenence
easy and muliple speed control.
low ripple distortion.

Answer / princealekota

Ac drive will have the more advantages compared to DC in
variable speeds less losses, less maintenance, robust etc..

but one advantage of DC drive is controlling of DC drive is
very easy compared to AC drive because, by controlling the
current we can control the torque in DC drive

eg: if u draw the equivalent circuit of Dc machine

Va ( armature voltage) = IaRa + La*(di/dt) + weLafif
Vf= IfRf + Lff*d(iff)/dt

md ( torque) = (p/2)*LafIfIa

So simply by varying currents we can control the torque.

in AC torque depends on the shaft speed, freq, slip etc..


even though the controlling is easy in DC... AC drive are
good for general purpose and the rest depends on the
requirement

Answer / abhishek goyal

Main part of industry to reduce cost if we go through DC
drive lot of disadvantage:
1 dc drive cost more then ac drive
2 dc motor more cost then ac motor
3 maintenance cost of dc is more (carbon brush etc.)
4 power loss is more in dc
5 need more size of cable (mostly copper cable)cost will
increase
6 we need more electrical equipment for dc drive.

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