On 2008-06-13, Karl Townsend wrote:
I can't get my 5 horse horizontal spindle to start in the higher speeds...
It trips the 30 amp circuit breaker ahead of my RPC. If anybody remembers, I
asked about this issue a week ago, adding capacitors and larger idlers lets
it start in lower gears,but I'm not there yet. It uses very little power
once up to speed.

I looked at a VFD. The way the control panel is wired, it would be hard to
install. There is a rotary switch that flips two leads for reversing
rotation ahead of a motor contactor. Estop logic can drop this contactor.

That is no problem -- you feed the motor directly from the VFD,
and use a selected three of the four terminals which flip the two leads
to select forward or reverse command to the VFD (dropping to 5V logic
commands instead of the 115 V ones which are currently in use.

There's start/stop pushbuttons on the operator panel for motor operation.

Most VFDs have the ability to accept the start/stop pushbuttons
(working at 5V) without problems.

All logic uses 110 VAC.

Not necessary (nor desirable) with the VFD. I'm sure that you
would feel more comfortable re-wiring the panel at 5V instead of 110 V.

Iggy suggested a soft start. see this example:
http://cgi.ebay.com/Siemens-Series-E...QQcmdZViewItem

That might do well.

I'd like to know how these things are wired in before dropping $100. Can a
soft start just be installed right in front of the motor? So if power comes
on the motor winds up slowly. Will it allow reverse rotation if two leads
are switched? Otherwise, I'll look for a VFD.

There, I can't help you, since I've never worked with one of
these. Perhaps go to the maker's site and download the manual if
possible?

Good Luck,
DoN.

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