Re: [CAD_CAM_EDM_DRO] Voltage, Current, Resistance and Heat?

> Recently, I changed out that driver board for the Hobby CNC driver
> board which is a chopper driver. I set this unit up at 1/4 step and
> it runs very smooth and I could achieve higher RPMS which is cool.
> But, in playing around with it for the last 2 days, I noticed
> another COOL thing, the motors barely get warm to the touch - they
> run very cool.
>
> After some tuning, I believe I have the torque pretty close on the
> new board as the old board. But still, the motors run cooler.
>
> This got me to thinking about something I read somewhere.
>
> "Torque is directly related to current"
>
> If this is the case, then, if I have the same current I should have
> the same torque. Also, I believe the motors should run at the same
> temperature.
>
> So, I am wondering if I could run more current (Amps) into these
> motors than what is given on the spec sheet. Eventually, I will be
> running them at about 40 volts when I get the parts for the new
> power supply. But, I am VERY tempted to crank up the current to see
> if I can get more umph out of them. Now I know I am not suppose to
> do that, but if the motors are running cool, I am wondering if I
> would in fact hurt them by running up the current while keeping a
> very close eye on motor temps.
>
> Any thoughts on this?

Many controllers reduce the current when the stepper motor is idle for a
while. That is enough to act as a brake. Full current is applied when
motion is required. The reduced current reduces heat loss and power
requirements.

Try running the X stage back and forth at full velocity for 30 minutes.
If the stepper gets hotter then they are reducing current when idle.

In general, I would stay within stepper manufacturer and driver
manufacturer recommendations.

Tom Hubin
thubin@...