Re: [CAD_CAM_EDM_DRO] boom - AWO?

Hi Hoyt,

Oh at least! Yes, I have "disable" switches, and use them all the
time. I suspect they disable the input signals to the 'H' bridge
outputs, or possibly disable a series "pass" transistor for the motor
supply voltage. I sure don't want to fight 180 oz/in of torque!

I'll probably just hang shaft encoders on them (for some experiments),
and continue to "jog" around.

Alan KM6VV


bjammin@... wrote:

>
> At 10:22 PM 8/5/02 EDT, JanRwl@... wrote:
> >> Now what I'm wondering, if the motor currents are off in either Gecko's
> >> or a Camtronics board (or other L298 driver), is the circuit protected
> >> against spinning the motor shaft (as in using a handwheel on the
> >> tailshaft of the motor)?
>
> For a while I used the handwheels to move the axes around, powered down.
> There is considerable resistance in this state. As someone pointed out, the
> steppers are connected thru the output stages of the drivers. That loads
> the steppers and makes them hard to turn. One day I had a failure on the
> two axes I'd been spinning most often and hardest. Next day, both worked
> again and have continued to work. I chalked that up to the ability of
> semiconductor devies to heal sometimes, and I always disconnect or use
> 'off' state in the drivers now, before manually moving the axes. So should you.
>
> Regards, Hoyt McKagen