On Thu, 17 Jul 2008 14:57:34 -0500, Ignoramus20788
wrote:

On 2008-07-17, Pete C. wrote:


Just have to set the current limits appropriately. Also with two stages
of belt drive, a slipping belt is more likely.

What you may find, and here I am NOT speaking from position of
knowledge, is that your big motor will draw big current even at low
load. What will change with load, is more power factor than current.


You're absolutely correct. I tried it to detect jams on a conveyor.
The current difference between unloaded and jammed was too small for
the VFD to discriminate. My lathe runs unloaded at about 60% current,
it's grunting at 70%.

--
Ned Simmons