Re: [CAD_CAM_EDM_DRO] Re: Lost Steps (Me again)

Ozzie@... wrote:

> All,
> To add to the mystery:
> I had told Tim that these motors were 150 in-oz motors, (much smaller
> than his), but this morning I just recieved identification of the
> motors from the Italian manufacturer, saying that they are 474 in-oz,
> 90 Volts, 4 Amps!

There is a language/convention problem here. If these motors REALLY
needed 90 Volts
across each phase to cause 4 Amps current to flow, they would dissipate
720 Watts, total,
and overheat in seconds. They also would be extremely slow as stepper
motors.
I think this spec is the maximum voltage ever applied to the motor, thus
this would likely
be the highest voltage you could input to a chopper-style driver.

> Could my current be set too low? The Camtronics board is putting out
> 37 volts and set for 2.86 amps.

Yes, you should run the motors at rated current to get the best
performance, in most cases.
Especially if you are having trouble with the motors stalling, you need
more current.
(In some wierd cases or severe resonance, lowering current can help.)

> Regarding the acceleration;
> I can try a lower number, but the problem occurs at low feeds, i.e.
> below 7ipm!

Extremely fast acceleration to very low speeds can EASILY lose steps! A
stepper
system must NEVER, even for one step, change velocity faster than the
motor/driver
combination can react. The more mass out there, the worse it gets.
Don't assume that
because you are only going 7 IPM you can't lose steps.

Jon