RE: [CAD_CAM_EDM_DRO] Re: blown Gecko - shorted output ?

Sound like you've got most of the bases covered. If you don't already have
one, you might try a ground connection between the negative side of your
capacitor on the DC power supply to the chassis ground (which will make it
the same reference voltage level as the AC side). Otherwise, the Geckos are
grounded, but the DC is floating in reference to the Gecko ground.

Regards,

Jeff

-----Original Message-----
From: turbulatordude <davemucha@...> [mailto:davemucha@...]
Sent: Wednesday, February 26, 2003 5:02 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: blown Gecko - shorted output ?


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Jeff Goldberg" <jeff@w...>
wrote:

> Dave:
>
> Bad idea to float the ground. You should make sure that the water

pipe has

> a ground clamp on the metal on the house side. It should give a

good ground

> through your house on the COLD water pipe as long as you do not

have any PVC

> portion or rubber fittings or such between where you are picking up

the

> ground and the water pipe ground clamp. If you have a metallic

wiring system

> (Metal boxes and BX cable rather than romex and plastic boxes), you

should

> be able to pick up a ground from your electrical raceway system.
>
> Floating ground -- BAD idea. You can hurt yourself if something

shorts to

> ground or destroy equipment with ground loops, static discharges,

etc.

> Grounding is a safety issue. If you have a problem with your

house's

> grounding system, fix that, don't try work arounds. If you go to

the

> library (its not on-line as far as I can tell) and pick up a

reference to

> the National Electric Code, it will talk about how to establish a

good

> grounding system.
>
> Regards,
>
> Jeff
>
>

<snip>

Short of testing the house earth ground, I am fairly confident it is
installed correctly. 1/4 alum 'wire' from the main circuit breaker
panel to a exterior earth gound. since the water system is
completely shielded from any exterior ground by the fact it turns to
plastic as it enters/exits the structure, no plumbing ground is
useful. Besides with the higher than expected ph, I'm planning on
replacing the copper with plastic in the fall.

All the recpticles are 3 prong, each box has a screwed in ground wire
(no clips) to the box, and each receptcle is wired to the ground
wire - wire nuts- not contact and prayer. all plugs are 3 wire with
all actually being connected to ground. nothing pulled out, no 3
into 2 adapters.

I am concerned that somehow the gremlins are going to and fro with
enthusaum and wreaking havoc with my circuitry.

Obvioulsy I'm pulling my hair and grasping at straws. I figured that
if all AC were strictly an only on the AC side of the power supply
and only DC on the DC side, I would not be having the problem. It
seems the ground is the only part that everything shares enough to be
close to the DC side. the ground is electrically (throught the
frame) connected to the stepper case. ditto to the Gecko heatsink.

Also, i figure the only other wires are the opto inputs and power
from the PC.

Besides, the DC side is by nature a floating ground. and the AC
negative is also ground, just not connected to the frame of the table.

I'm missing my pnuematic days. then I could hear the leak or not hear
a blockage.

Dave