Bridgeport Series I 8-wire stepper (Sigma) current rating

> From: turbulatordude [mailto:davemucha@...]
> Sent: Thursday, September 05, 2002 6:54 AM
> Subject: [CAD_CAM_EDM_DRO] GUIDE TO STEPPERS and wire in parallel or
> series AND 8 wire series connection
>
> ....
> ===============================================
> Message 40388 "mariss92705" Fri Feb 22, 2002 2:41 am
>
> ....
> The conclusion is: set the current to the motor's rated current. If
> it is a unipolar (6-wire motor) use the nameplate rating. If it is a
> parallel wired 8-wire motor, use the parallel rating.
>
> UNIPOLAR: Use the motor's name plate rating
> SERIES: Use one-half the parallel rating
> PARALLEL: Use the motor's name plate rating (usually the parallel
> rating)
> FULL-WINDING: Use one-half the name plate rating
> HALF-WINDING: Use the motor's name plate rating

Ken,

Thanks for re-posting Mariss's message.

I think I'll try half winding. As I understand it this should give me good
rapids, almost as fast as parallel but without the current demands of
parallel.

Can anyone tell me what the "name plate rating" of the Bridgeport Series I
8-wire stepper (Sigma) motors are?

This is a 1981 vintage machine. I can't find a name plate on the motors. I
assume they are Sigma motors because one of the wiring diagrams that came
with the machine shows the 8-wire motor as an 'alternate' wiring
configuration and the diagram is labeled 'Sigma'.

I will be using a chopped, microstepping driver (12 amp Ahha RC-500). Any
recommendations on if I should use full, 1/2, 1/4 or 1/8 stepping?
Tradeoffs involved?

I'd like high rapids and I don't need lots of force on the low end (In a
home shop I tend to use lighter cuts than I probably could).

Cheers,

Chuck Hackett
Omaha, Nebraska, USA
7.5" gauge UP Northern 844