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Document Type: Prentice Hall
Author: Thomas E. Kissell
Book: Industrial Electronics
Copyright: 2000
ISBN: 0-13-012697-7
NI Supported: No
Publish Date: Sep 6, 2006


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Selecting the Proper Size Stepper Motor

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When a stepper motor is selected, eight different things must be considered:
  1. Operating speed in steps/second
  2. Torque in oz-in.
  3. Load inertia in Ib-in.2
  4. Required step angle
  5. Time to accelerate in ms
  6. Time to decelerate in ms
  7. Type of drive to be used
  8. Size and weight considerations

Some of this information will be provided from application specifications, such as the size and weight considerations, step angle, and the operating speed. Other information must be calculated. Several formulas are provided to help you with these calculations.

Calculating Torque
The formula for calculating the torque is

Calculating Load
The formula for equivalent inertia to overcome friction in the system and enough torque to start or stop all inertia loads is

Frictional and Rotational Acceleration Considerations
The formula for calculating the torque required to rotationally accelerate an inertia load is

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Reader Comments | Submit a comment »

this is a Very nice representation, as for the previous comments, I think Its quite Clear the commentor's equation is mathematically the same one presented in the article by the author since we're multiplying by (1/2) eitherway.
- Achraf M Fahmy, Higher Tech Inst. - Mar 7, 2012

Correction to inertia equation
Overall, this is good information for the professional hardware developer and hobbyist alike. However, the second equation for calculating inertia is incorrect. The correct equation is I = [W*(r1^2+r^2)]/2.
- John Yarbrough - Oct 3, 2011

nice information
in the doucment the information given is very use full thanks 2 authour
- nirmal, n++. - Feb 12, 2008


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