Re: ON topic- More Y-axis OverVoltage- Random consistentcy frustration

On Oct 12, 11:51 pm, clay <a_des...@xxxxxxxxxxx> wrote:
Still fighting a Persistant Y-axis OverVoltage error.  The machine will
run fine for hours at a time, then suddenly alarm the Y-axis and shuts
down.

But here is a consistent symptom. Yet completely random.
It ONLY happens during the first programmed Z-axis rapid/plunge move
when the spindle is running HIGH RPM. Never at low RPM. And never
consitently. Only 1 out of 20 times or so....Vibration? Current drop?

Mori first suggests the Y-axis motor harness is chafing somewhere. So
far no evidence of this. More inspection required. Second suggestion,
(by everyone) Bad brushes/armature. Inspected & cleaned (D.C. Servos)
Next step, get the motors armature re-surfaced., if only we could finish
the current job, first.

Will swap x & y cables to see if the problem moves, next. (cable or motor?)

Any more ideas?

ca

While the motors are out, be sure to have them baked. I forgot that
part before.
Also, you might have coolant contamination of the cables/connectors
themselves.

The fact that you need a Z plunge indicates that the Z drive is in
regen mode (Suddenly! acting as a generator)
The Z driv eis holding up the head, and then Suddenly! letting it go,
and getting power back from the motor.

The load dump (braking) resistor is suposed to burn that suge of power
and prevent the DC bus from going high. (Overvoltage)

I don't know how to inspect the braking resistor circuit.
You could start and stop the spindle repeatedly, and check to see if
the braking resistor is getting hot, (Don't touch it unless you like
to get fried, yourself).

Somebody else should have a better idea how to test the braking
resistor.
Doesn't the Haas or Fadal use a heating element from a stove?
Along with the resistor itself, there is the circuit inside the power
supply that dumps the bus to the resistor.
Some machines also have a circuit breaker in the braking circuit.
.

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