Re: Advice needed - Mariss' e-stop circuit

If you just want a end-of-day crowbar, then you don't need any
switches. power is on when AC is present and the relay will change
state upon powering up. and will drop out when powering down. you
could use the on switch for power up if you like.

If you don't need to use this as an e-stop, but just a motor stop for
a tool change, you could control the relay in software. that would
require additional components, a darlington to power the relay is one
possibility.

for the power off and using a single momentary, you could use a DPDT
momentary as one option. that way the center could be an open
circuit (on use) or closed (open on switch).

or, you could just add a second relay for the off. that would then
allow the circuit to be broken with a completed circuit and not
breaking a curciut. A second relay might be easier than a circuit
board.

Dave




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Tom Murray
<thomasm923@a...>" <thomasm923@a...> wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude
> <davemucha@j...>" <davemucha@j...> wrote:
> > Hi Tom,
> >
> > if you are looking for an enable/disable for the circuit, the
> > momentary listed as the e-stop is the on/off switch. All it does
> is
> > open one leg of the DPDT relay coil.
>
> Dave,
>
> No, I am only looking to put an on-off switch on the front panel of
> my power supply. I don't want to use the e-stop to turn the power
> supply off at the end of the day.
>
> > As it is listed, the on momentary and off can be s single on-off-
> on
> > double pole momentary.
>
> Yes, but in order to interupt the current in the relay coil, the
> circuit must be opened briefly. So one side of the momentary switch
> must have some additional circuitry that will open the circuit when
> the switch makes contact. Right?
>
> I need advice on how to make this additional circuit.
>
> Thanks,
> Tom Murray