Re: [CAD_CAM_EDM_DRO] Chopper max voltage?

This is not normal behavior unless you have the chopping frequency set to a
value which is too slow. The chopper
will notice that the current has reached setpoint, turn off the l298 and
then not turn it on till the next clock pulse.
During this time the current in your winding has decayed
so no torque.You are then driving it with short duration spikes. Raise the
frequency of chopping and the 298 will turn on sooner. The lower voltage
doesn't have this problem due to the increased amount of time required to
build to setpoint current.

This might be your problem.

Art

----- Original Message -----
From: "Greg Nuspel" <gregnuspel@...>
To: "CAD CAM EDM DRO" <CAD_CAM_EDM_DRO@egroups.com>
Sent: Tuesday, October 03, 2000 3:46 PM
Subject: [CAD_CAM_EDM_DRO] Chopper max voltage?


> I hooked up a higher voltage power supply to my stepper controller. It
uses
> L297 and L298 chips. It appeared to me that the chopper was working too
> well. That is the steppers didn't have any torque. I hooked up a variac to
> the supply and lowered the voltage. When the voltage came down to about 12
> volts the steppers started to move again. Is this normal behavior or could
I
> have something set up wrong?
>
>
> -- Greg Nuspel
>
>
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