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Electronics used before a Servo Drive
Electronics used from incoming 208VAC 3-phase power to a servo drive.

I have 208VAC, 3-phase and it will be sent to a servo drive to power servo motors. My question is i initially had:
CB-->Filter-->motor starter-->servo drive

but can i do it this way:
CB-->Filter-->contactor-->fuse-->servo drive


I do it this way with one contactor for up to 6 then use fuses for each.


If it was larger drives I would split them up.


By William Sturm on 25 August, 2005 - 2:02 pm

Put the fuses first, if possible. They are to prevent
wires from burning in case of a short circuit. If CB
means circuit breaker, then it may be OK.

If the cb is for a branch circuit, then you
should put cb-|->fuse-->filter/contactor-->drive.

The reason is that if the filter and contactor are the same ratings as the drive, you need to protect it at a lower current than for the whole branch. Another thing, the fuse must be coordinated with the cb. This means that the fuse must open first before the cb or the wires to motors may fry if it takes too long for the fuse to go.