Re: [CAD_CAM_EDM_DRO] Digest Number 3232
Posted by
Don Rogers
on 2003-07-14 10:10:27 UTC
At 03:45 PM 7/14/03 +0000, you wrote:
side. A lot like your PC, and a Printer. Both have frame grounds
connected to AC Ground. You connect them together with a grounded cable
and effectively set up a ground loop. The important thing here is that the
loop is as short as possible, and external to the logics of both
machines. And both machines here are designed to work in this manner. For
your controller, I would use a single power line if possible. If you use
two, make sure your house AC wiring is correct. You can pick up a test
plug at the hardware store for around $5.00 and check it. Also if you are
splitting the input AC between two outlets, make sure they are both on the
same side of neutral, You don't want 240V into your box, unless you are
running a 240V power supply.
While on the subject of Ground loops, I've been thinking about the stepper
wiring, and table/slides grounding. Pacific Scientific recommends that you
use shielded cabling for your steppers, and ground it at the controller end
and float it at the motor end. This leaves the motor and it's driven slide
at the mercy of the ways for providing ground. On a mill, you will have
two sets of ways between the table and frame ground of the mill. I am
going to run braided wire from the frame ground to each slide to provide a
ground to the motor frames I am using optical limits so I need to keep a
clean signal line. This method allows the motor frame to be on tip of a
branch, and the shield on the motor cable to be the other.
Don
>My question is, I want to put a 10A power entry module so I get itYes, if for nothing else, it gives a cleaner cabling job
>all in one plug. Is this a bad idea?
> Can I put 2 of these modules andYou can do this, and you will get a ground loop, but it will be on the AC
>split the power between say #3 and #4 + controller electronics power
>and the put #1 and #2 on a seperate power cord? This way I would have
>2 AC power cords entering one box. Is there a problem with ground
>loops if you do this?
side. A lot like your PC, and a Printer. Both have frame grounds
connected to AC Ground. You connect them together with a grounded cable
and effectively set up a ground loop. The important thing here is that the
loop is as short as possible, and external to the logics of both
machines. And both machines here are designed to work in this manner. For
your controller, I would use a single power line if possible. If you use
two, make sure your house AC wiring is correct. You can pick up a test
plug at the hardware store for around $5.00 and check it. Also if you are
splitting the input AC between two outlets, make sure they are both on the
same side of neutral, You don't want 240V into your box, unless you are
running a 240V power supply.
While on the subject of Ground loops, I've been thinking about the stepper
wiring, and table/slides grounding. Pacific Scientific recommends that you
use shielded cabling for your steppers, and ground it at the controller end
and float it at the motor end. This leaves the motor and it's driven slide
at the mercy of the ways for providing ground. On a mill, you will have
two sets of ways between the table and frame ground of the mill. I am
going to run braided wire from the frame ground to each slide to provide a
ground to the motor frames I am using optical limits so I need to keep a
clean signal line. This method allows the motor frame to be on tip of a
branch, and the shield on the motor cable to be the other.
Don