Re: [CAD_CAM_EDM_DRO] Stepper question

David Micklethwaite wrote:

> I have two oldish single stack stepper motors. One is labeled 2.9V 3.3A the
> other 3V 1.7A. Am I correct in thinking that the 3.3A motor will have almost
> twice the torque of the 1.7A motor?

If they about the same age, then it's likely but certainly the 3.3A will
be more powerful.

> The labels say that tis is the voltage and current per phase. What's a
> phase?

You do not say if they are 4, 6 or 8 wire. I'm lead to believe that the
current rating is as if the motor was a 4 wire motor, so in the 8 wire
case, the two windings on one 'side' are wired in parallel.

> Mariss' white paper on steppers suggests that a "half winding" connected
> motor delivers twice as much power as a "full winding" connected motor. He
> also says that for a "full winding" connected motor the drive current should
> be set to half the "rated unipolar current". Is this the current per phase
> that is shown on the label?

Half winding is parallel mode, and an 8 wire motor would have the two
halves wired in parallel, while full winding is serial mode, so one end
of a pair is linked to the opposite end of the other pair and the free
ends give you your connections. This has half the current rating of the
per phase value.

But if you only have four wires the above is not relevant and you only
have "full winding" mode anyway :)

--
Lester Caine - G8HFL
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