Re: [CAD_CAM_EDM_DRO] I let the smoke out...

On Sat, 13 Sep 2003 22:53:29 -0400, you wrote:

>Oops.
>
>Well, got everything wired today, and it
>looked like I was going to see motion at last.
>
>Plugged it all in, fired up the computer portion, switched on the motor
>power portion, saw that the Geckos had power, computer was humming
>away fine, and satisfied, shut it down and moved it over to the mill.
>
>Plugged in all back in and grabbed the three cables for the motors.
>Connected a motor and "***BZZT***, **FLASH~!** **WHOMP~!!!!!**"
>
>Oops. There goes the smoke...
>
>Has anyone ever gotten the smoke back inside?
>
>Seems I blew up my regulator on the home-made power supply.
>
>Any ideas why? (besides my being an idiot?)

OK, if you got the standard type of 3 terminal regulator (a la radio
shack), it is a 7805. The 7805, unlike the chip that Mariss uses, has
an input voltage limit of 35 volts for any regulator from 5 to 18
volts. If you connected it to the 80 volt line, you zapped it.

I'd recommend a separate 5 volt supply, or a 12 volt supply running
the regulator. Any voltage from 9 to 15 or so would be fine, with the
lower voltages preferable to keep down the regulator dissipation. At
5 volts at one amp out, with 12 volts in, the regulator needs to throw
away 7 watts of power.. so heatsinks are a good idea.

I am guessing that this is the case...

Harvey

>
>Thanks,
>
>Weyland
>