Re: NEED HELP PLEASE!!!!!

Jesse,

I have just finished redoing my Boss 6 Bridgeport mill. I assume the
motors are similar. Mine are Sigma motors but I bet the specs are
the same, although I don't know that for a fact. Below is what
someone sent me on mine. I also have a 2:1 reduction and a 5 pitch
ball screw.

Sigma Instruments 21-4266D200-F022 specs as follows
8 leads
Torque at 50 SPS 910 oz/in bipolar, 20% less for unipolar.
Holding torque 1100 ozlin, 20% less for unipolar.
Detent torque 38 ozlin.
Phase current amps unipolar 9.0, Bipolar 12.7 Phase restance .21
ohm.
Phase inductance 1.6mH.
Rotor inertia 37.1 oz-in squared.
Weight 19 1bs.
series 21 "" High speed, high torque thru 4500 rpm.
4266"" 4.2" dia and 6.6" long 2 stack rotor.
200 steps per rev.

You can recognize the brand Superior vs Sigma by the pattern of
screw terminals where the wires attach. I have the manual with
photos of this if you need to confirm. The sigma motor have 2 rows
of 4 screw terminals aligned parallel. The Superior motors have a
screw pattern that is not aligned in a straight row.

I was advised to set mine up in half-winding mode but it was tricky
and caused at least 2 Gecko drives to get damaged due to improper
connecting. I finally purchased new motors but found later that
there was nothing wrong with the original motors. I had them
running at 7 amps with a 75vDC power supply.

I hope this is of some help to you. I know how frustrating the
whole process can be. The stepper motors are working very nicely
for me now, especially with Mach2 software. I knew nothing about
electronics and little about CNC except what I experienced running
my machine before it went down and I revamped it. I did find this
discussion group to be very helpful and also found the servo bias.
By the time I had spend a lot of money and started to get the advice
to switch, I felt it not cost effective to switch to servos.

I really think you can get the original motors to work and I wish
you luck.

Keith Clark


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "therebel344"
<rebel307@b...> wrote:

>
> I got a BP BOSS series2 mill. I am getting all kinds of

confusion

> as to what voltege and amps the steppers need. I know there were 2
> different steppers used there was the superior and the sigma. If I
> am not mistaken my steppers are superiors. On the inside of the
> motor end cap there is a wireing diagram and it tells the the p/n
> number, 025805 this is an alternate motor for p/n 026744. Does
> anyone know the voltege and amps these motors need to run

properly.

> I posted a time or 2 already and got an email box full of
> suggestions to upgrade to servo. I would like to upgrade to servo
> but my bank account does not permit it. These motors drive the
> screws through a 2:1 belt ratio if that helps give any clues as to
> the requirments of them.
>
> Jessie