Re: the L6203 & L297 circuit heats up stepper when not clocking?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "zarzul" <aminear@b...> wrote:

>
> Well got it built, but it would not do anything. After a couple of
> days of head scratching, oscope and multimeter, could find what was
> wrong. Then I cut the sync line going to the second L297 (I was
> running two on the same board for X & Z axis with osc. sync'ed) and

now

> it seems to work fine. Only one problem, BIG ONE. The motor heats

up

> even when stopped, no clock. If I turn the enable off it then it
> begins to cool. I think I will try killing the circuit I have that
> switches the Vref pot in or out of the circuit via the INHIBIT

lines (I

> have an AND gate that turns on a transistor that puts ground on one

leg

> of the Vref pot, if the INHIBIT goes low it allows Vref to float to
> +5). I am not sure if this will help, since I think if your are

not

> stepping the motor, the chopper won't chop anyway.
>

I think it's inevitable that the motor will get hot even when not
stepping (if that's what you mean by clock) 'cos the circuit is busy
feeding current through it to keep it stationary - i.e. to maintain
the holding torque.

John.