RE: [CAD_CAM_EDM_DRO] Re: CMD-260 test mode?

Thanks for getting back to me. My concern is that I've tentatively
identified the NEMA 42's as having a nominal voltage of 2.1 volts and a
current rating of 9 amps. According to the white paper on Gecko's site,
they recommend that the voltage be kept to less than 25 times nominal to
prevent motor overheating. I figured the 28 volts I was going to use was 10
times nominal rating and I'd pump up the amps to the drive limit (8 amps).

Half of the advice I've gotten off the chat group has told me to run the
voltage low and use half winding and keep the current low. Half the advice
is to run balls out on both voltage and current. A third half is telling me
to raise the voltage above the advice Gecko (I'm using CMD-260, from a Gecko
competitor, but I assumed the advice was generic) is giving and run the
current low.

I've rebuilt the power supply three times in the past week and I'm all
confused.

Jeff

-----Original Message-----
From: stevenson_engineers <machines@...>
[mailto:machines@...]
Sent: Tuesday, February 18, 2003 7:46 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: CMD-260 test mode?

Jeff,
With the combination you have of the 260's and the 42 series motors
you will need all the power you can get.
The 260's are rated for 80 volt at 8 amp and it would be adviseable
to get somewhere near these limits.
With a 50 volt AC supply, by the time it's rectified and smoothed,
you will have 70 volts DC which is close enought to 80 volts but not
too close to cause over voltage problems.

John S.

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

> Well I'm nearly there. I've got a power supply, 3 CMD-260 drives

and

> a Bridgeport with NEMA 42 steppers on the XY and Z axis. I still
> have to get a PC connected and load some software (thinking of MACH
> 1 - pros and cons would be appreciated).
>
> Until I get the PC hooked up, I'd like to test the drive/stepper
> combination. (The motors are unmarked and I'm taking some best
> guesses at an appropriate power supply. I'm going to try 34 volts

at

> 8 amps in parallel and see how hot the motors get. I can still
> change it if things go squrilly). Anyone know if there's a way to
> test them to see if everything works in the absence of the PC,
> software, etc.? Can I test them unloaded or do they have to be
> attached to the Bridgeport?
>
> If not, can a PC be used to test in the absence of CNC software?
>
> Thank for all the help.
>
> Regards,
> Jeff