Re: [CAD_CAM_EDM_DRO] 4 phase PM type stepper

Hi Peter,

No problem! IMO, these motors (Unipolar!) are not what we really want
for CNC. They're not well suited for Camtronics & Gecko's. They are
usually driven by L/R drivers. They appear to be similar to some I
have, used for simple positioning.

48 steps/rev. would give you lousy resolution. The app. I saw them in
had a pair of 3:1 timing belt pulleys, giving them 9:1, or 432
steps/rev. These rotated a "valve" for some sort of infusion device.
Another turned a leadscrew, and moved a pin along a precision 1/2"
shaft/ball way. The torque is quite low, I didn't convert it, but mine
appear to be 40+ oz/in. You want some? I think I still have a case of
'em in the garage!

I'd think "PM" type is Permanent Magnet. 600 pps rate; They're not
expecting any high speed stepping! "4-phase" usually implies that there
are four coils, often driven in a "wave" (single coil at a time).
"2-phase" can be thought of as a pair of coils/windings, with a 90 deg.
phase relationship, each driven by an 'H' bridge (so that the current
through the winding ca be reversed. See the URL's posted a day or two
ago on stepper theory by Ballendo.

Look at Sherline's motors, or find a similar "surplus" motor!

Alan KM6VV


cadcamcenter@... wrote:

>
> Hi,
>
> Hoping for some answers for the hopefully not too irritating
> questions:
>
> MOTOR SPECIFICATIONS:
> No. of phase : 4 phase PM Type (pulse modulation?)
> Step angle : 7.5deg+-5%
> voltage : 5
> winding resis: 70 ohm
> winding induc: 30mH (1Vrms 1kHz)
> start pulse rate: 600pps
> slew pulse rate: 610pps
> holding torque : 180g-cm
> no. of wires : 6
> QUESTIONS:
>
> What is the difference between 2 phase and 4 phase steppers?
> Are 7.5 deg. steppers good enough for CNC work?
> What is starting/slewing pulse rate? What significance does it have
> for motor controller?
> 1g-cm = ??? oz-in (sorry, but someone on the list will be able to do
> this conversion without having to hunt for conversion tables)
> Will the motor be compatible with those CCED motor controllers
> (gecko, camtronics, etc.)
>
>
>
> Addresses:
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