Dave Tweed wrote:
>
> Wagner Lipnharski <wagner@USTR.NET> wrote:
> > Supposing it could be possible, what would happens if you wrap a secondary
> > coil (with the diode) around the actual relay coil?
> > All the magnetic collapsing field would be drained by this secondary coil
> > in short (by the diode), with few energy generated at the primary coil, is
> > this correct or not?

> The actual turn-off time of the relay would be essentially
> unchanged, and this is what we were trying to improve.


Exactly, and the easiest way to get the fastest
coil field collapse is to just use no catch diode
and have a switching transistor rated for the
250v spike that the coil produces.

The only faster way to get the field to collapse
is to reverse the *current* at turnoff by
applying a voltage, which would in effect "squash"
the field as someone mentioned before.

But if the field collapsing into an open circuit
produces 250v, wouldn't forcing it to collapse
quicker by using a reverse current source cause
this back-emf voltage to spike even higher??
And doesn't that mean the reverse current source
must have a voltage greater than 250v to have an
effect?
-Roman

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