Recently we had a contractor update a piece of
equipment that has 20 pay off shafts that employ PM
motors to power push or pull the shafts to maintain
tension and dancer position.
Out of these 20 units that were updated, at least
5 drives went belly up when power was applied to the
machine. (all drives run off the same source of 230V).
3 of them had shorted SCR bridges, one lost it's
15 volt power supply while the last one for some reason
thinks when the drive is to go in the forward direction
it detects an overload with no actual voltage being generated
at the bridge for the A1 and A2 lines! also, Amp meter indicates
that there really isn't any current being generated! So i can
only assume something is wrong with the max current sense for the
forward direction ?

In any case, what is the chance of these drives being shipped
in this condition ?
this is the NEMA 240D regen 1/2 Hp 120/230 volt drives.

Personally, i think the guy may have had the voltage set wrong
on the defective units?

--
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"Jamie" t wrote in message
...

In any case, what is the chance of these drives being shipped
in this condition ?
this is the NEMA 240D regen 1/2 Hp 120/230 volt drives.

Personally, i think the guy may have had the voltage set wrong
on the defective units?

Usually these run 90 VDC motors. We used a lot of them (120 V model) and
only had one failure - a dry joint on one. But they usually do have to be
jumpered for the right voltage.