how to magnetize stepper motor magnets

[bault]

Hi
I designed and build my own stepper motors the motors work fine its just that I think the magnets is not magnetized the right way, the magnets came from China already magnetized when I turn my motors by hand it will step 50 steps per revolution but it should be 200 steps, the motors works fine under power but should supply more power when magnetized differently.I belive that stepper manufacturers magnetize the motors only after the motors was assembled and would like more information on how it is done.
Regards

 

[jclough]

Stepper manufacturers do indeed magnetize the rotors after the motors are assembled. They normally use AlNiCo magnets and magnetize them axially. Each magnet has two fifty tooth pole pieces each oriented one half tooth pitch apart.

Even so, a normal 1.8 degree stepper will have only fifty detent positions in one revolution. The motor windings are what increases the number of step positions to 200 steps/rev.

 

[SERVOCAM]

For 200 steps/rev, you have two sailents, a set of 50 North magnets on the first, then an offset set of 50 south magnets. This is known as a stack. So ther are 100 alternating N-S magnets total. Your hybrid stepper, 200step/rev or 1.8 deg/step motor has 2 windings (A & B, 1 & 2, what ever you want to call them).

2 windings x 100 magnets = 200 step/rev (under full stepping drive).

Are you saying that you can only geel 50 step/rev when turning it by hand, but when on a drive, it gets 200 steps/rev?



Cameron Anderson - Sales & Applications Engineer
Aerotech, Inc. -

http://www.aerotech.com

"Dedicated to the Science of Motion"

 

[bault]

To Cameron a Anderson
Yes to your last question

 

[jbartos]

Suggestion: The stepper windings are increasing number of steps under motor energization. This is already stated in jclough posting.