Re: L298 goes boom on my camtronics :(

I have to concur. Back emf is generated in any windings if current is
suddenly turned off. The key here is that the windings carry current
even when the motor is not turning (holding current). If you don't
know that the motors have holding current then you have a legitimate
excuse for doing the wrong thing - that is disconnecting the motor
under power - otherwise there is no excuse. I'm no electrical
engineer and many of the things discussed here go over my head but
this is basic and anyone with any electrical training should know it.

Eric

--- In CAD_CAM_EDM_DRO@y..., RichD <cmsteam@s...> wrote:
> Hoyt,
> You are quite wrong. Any inductance carrying current will generate
large
> voltages when disconnected as the flux field collapses.
The "moving" is not
> mechanical. It's magnetic. This is a basic electrical, natural fact
of nature.
> Touch the motor leads together where you can see them. A spark will
be seen.
> RichD

> > Not at all. I've dis- and re-connected mine under power any
number of
> > times. There is no back EMF in a stepper that isn't moving.
However,
> > turning a stepper which isn't under power does turn it into a
powerful
> > pulse generator.
> >
> > Regards, Hoyt McKagen