On 25 Sep 2012 00:27:07 GMT, "DoN. Nichols"
wrote:

On 2012-09-24, Ignoramus11519 wrote:
On 2012-09-24, Jon Elson wrote:
Ignoramus11296 wrote:


http://igor.chudov.com/tmp/Lagunmati...lling-Machine/

It powers up, the brake resistors are burned.

[ ... ]

If it has a standard 3-phase motor for the spindle, then it may be
easier to replace the whole VFD than mess with repairs. Most likely

[ ... ]

I spent a while on my knees today in front of that VFD.

It is a Yaskawa G3 branded Saftronics.

Supposedly, even with the drive wired for remote operation, I could
make the motor jog by pressing the jog button on the keypad.

Unfortunately, pressnig the jog button seems to do nothing, 00.0 is
displayed as frequency and the motor does not jog.

Absence of the brake resistor should not prevent a jog (or a
normal forward or reverse operation), just make it slower to get down to
a stop, so the jog would likely overshoot the target position.

This is the spindle motor, is it not?

My main question, as of right now, is how can I establish the
condition of the power module. How can I find out if it is good or
bad?

Can you identify which leads feed the motor?

What horsepower range does the motor have?

Do you have a spare VFD somewhere within perhaps half that
horsepower range?

If so, you should be able to re-connect the motor to the spare
VFD and test it by spinning the motor up.

If it doesn't -- consider the motor winding to be a likely
problem. Measure resistance between all three lead pairs. If any one
is different from any other (other than a few percent), it is the motor.
An open or a shorted winding. (But the VFD should display an error
message in the case of a short, and it should show a virtual speed in
the case of an open -- at least until the current in the one remaining
path is enough to force an error message.

If it does spin the motor up -- then back to the original VFD.
Is it possible that you need some other signal to enable the operation?
Perhaps an axis limit switch is enabled, blocking operation?

And there are lots of options to most VFDs. Perhaps one has
been set to inhibit jog operation?

Back to the brake resistor. Have you pulled it and measured its
resistance? If it is shorted, it will probably prevent motor operation
totally -- unless it is disconnected.

The other option is the failed brake switch resistor.

Or perhaps something got into the logic and fried it, but if
that were the case, it would probably not even be able to display the
0.00

Good Luck,
DoN.


Correct. It should show an error code upon start up.

VFDs are pretty sharp....

Gunner

--
"Confronting Liberals with the facts of reality is very much akin to
clubbing baby seals. It gets boring after a while, but because Liberals are
so stupid it is easy work." Steven M. Barry