Which Stepper?

jlada · Oct 6, 2002

In checking catalogs, i find steppers with different volt/amp configurations producing the same torque. The configurations produce the same wattage values so this makes sense, however, i don't know which to select for a given application.

For example, from the Sanyo Denki StepSyn catalog (NEMA 34):
motor 1) #103H8223-0441 887oz-in, 11.2v, 2.0A, 5.6R, 24mH
motor 2) #103H8223-0941 887oz-in, 5.4v, 4.0A, 1.35R, 5.6mH

The only thing that comes to mind is that the motor with the lower resitance/higher current might reach it's rated torque quicker each step. This may allow for greater acceleration. What other differences would these two motors exhibit if not that?

Thanx,
Jeff

jbartos · Oct 6, 2002

Suggestion: Visit

http://www.njr.co.jp/pdf/ee/ee05003.pdf

and notice:
Hysteresis losses in motors
With some low-inductance motors, chopper-type drivers can generate increased iron losses, caused by the
winding current ripple. To minimize this problem, use a high chopping frequency and do not use a lower
inductance than needed to get maximum-required step rate—it is also possible to use a lower chopping voltage.
In most applications, the hysteresis loss related to the chopping current ripple is low compared to the hysteresis
loss related to the stepping current changes. If chopping current ripple is kept at or below 10% of the nominal
current, this normally doesn’t cause a problem.
Comment: This excerpt is supporting the 24mH motor since it has the higher higher inductance than the other motor, i.e. 5.6mH; and the lower stepping current changes.

SERVOCAM · Nov 4, 2002

In checking catalogs, i find steppers with different volt/amp configurations producing the same torque. The configurations produce the same wattage values so this makes sense, however, i don't know which to select for a given application.
For example, from the Sanyo Denki StepSyn catalog (NEMA 34):
motor 1) #103H8223-0441 887oz-in, 11.2v, 2.0A, 5.6R, 24mH
motor 2) #103H8223-0941 887oz-in, 5.4v, 4.0A, 1.35R, 5.6mH
The only thing that comes to mind is that the motor with the lower resitance/higher current might reach it's rated torque quicker each step. This may allow for greater acceleration. What other differences would these two motors exhibit if not that?

Jeff, ignore the voltage, res, and the rest of the specs. They will just confuse you. What you need to do is calculate how much torque you will need to accelerate the load. Most mfgs that build stepper drives will have a list of their compatible motors (if they don't, then don't buy from them). Select a drive/motor combo that works best for you.

Check out:

http://www.superiorelectric.com

http://www.pacsci.com

http://www.compumotor.com

http://www.idcmotion.com

http://www.imshome.com

http://www.amci.com

http://www.orientalmotors.com

http://www.nycon.com

http://www....there

are many more.

Cameron Anderson
Sales & Applications Engineer
Aerotech Upper Midwest

http://www.aerotech.com

"Dedicated to the Science of Motion"