Answer / tanmay maheshwari

Variable frequency Drives(vfd) are used for controlling the
speed of AC motors by changing the frequency of power
supply. the advantage of using them is they can be used for
multiple machines having various ratings. The
cycloconverters are used for the conversion purpose.
they are used for ventellating purpose, in pumps etc.

Answer / anil

Variable frequency Drives(vfd) are used for controlling the
speed of AC motors by changing the frequency of power
supply. the advantage of using them is fast and accurate
and more controlled and relaible device they can be used
for where speed is very important such as CNC ,machin
tools , special purpose conveyer m/c etc.

Answer / sakkaravarthi soganur arakonam

VFD variable frequency drives and also known as vvvf
variable voltage variable frequency and also konws vsd
variable speed drives,vfd works on v/f ratio means if
frequency increase voltage will increase at rated voltage
if frequency will increases voltage ramainig constant

its used conveyors ,cranes,higer LT motor,

length of 4 core cable 95mm from substation LV VFD panel to Motor at field approximately 150 meter. Motor stop and power has been isolated from LV MCC ( Substation )to disconnect Motor for services. After Motor completed service propose to reinstall and reconnect Motor Cable, found earth cable sparkling during touching at metal / motor body. Inspect by clamp meter found earth cable have current flow AC 1-2amps and all earth cable at MCC LV also have current flow as same value. why it is happen?

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