Re: simple stepper power question.

Mariss -

Tried your procedure yesterday evening on a small motor of unknown
power (other than it was marked 1.1A/phase 4V, 6-wire motor) and a
25V supply, driven via L297/298.

Measurements using 1/2 and full coil at rated amps yielded reasonably
sensible numbers - the motor looks to be about 60 oz-in. Just to see
what would happen, I upped the L297 current setting to 2 amps and re-
measured, still on full coil. (Yes, I know - the motor *did* get
warm <g>). The measured supply current under load actually *reduced*
relative to the supply no-load current under these conditions.

Any theories?

Regards,
Tony

--- In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...> wrote:
> Dave,
>
> Yes there is. All you need is a multimeter and a calculator. Do the
> following:
>
> (1) Measure your DC voltage accurately
> (2) Set the meter to DC Amps
> (3) Put it in series with the power supply to the drive
> (4) Run the motor at a known speed (greater than 1 rev / sec)
> (5) Measure the power supply current at no load on the motor
> (6) Now the tricky part. Load the motor down and note the current
at
> the moment the motor stalls. This may have to be repeated several
> times to get an accurate reading.
> (7) Take the difference between the no-load current and the stall
> current. Multiply the result by your power supply voltage. The
> product will be the motor output power in Watts mechanical.
> (8) The torque at that speed will be: oz-in = Watts * 4506 / full
> steps per second
>
> Mariss
>
>
>
>
> --- In CAD_CAM_EDM_DRO@y..., "dave_ace_me" <davemucha@j...> wrote:
> > is there a formula to determine power of a stepper ?
> >
> > I have a Slo-Syn NEMA 34, 1.7 volt, 4.5 amp
> > single stack.
> >
> >
> > Also, has anyone put together a simple test
> > for stepper power ? Seems like a weight,
> > and a long crank arm with holes drilled
> > each inch would allow one to keep moving
> > the wieght farther out until the motor
> > started missing steps.
> >
> > Dave