TMorita Senior Heliman Location: SF Bay Area, CA
| The effect you noticed is called "cogging" ...
It depends on the motor construction. If the motor has an iron core for the windings, then the magnets on the shaft are attracted to it, so it's difficult to turn the motor shaft by hand because you need to pull the magnets away from the metal. (Astroflight, Mega, Aveox, Plettenberg Model Motors, etc motors)
If the motor has no iron core for the windings, then the magnets on the shaft aren't attracted to anything, so it turns smoothly when rotated by hand. (Hacker, etc motors)
Toshi |