|Title||05. Why motor shaft of Ezi-SERVO slightly moving once power inputs?|
It is the movement by step position aligning.
Before power input, the rotator of a motor(motor shaft) locates at a random position within 1.8º(1 step). After power input, it executes magnetization through by winding wire of A-phase of the stator and the nearest rotator(motor shaft) from A-phase moves to the stable initial position. So, movement occurs. It is called a STEP ALIGN.
Normally step motor from FASTECH is Hybrid and Bi-Polar type. It has 50 teeth of rotor (tooth pitch 7.2º) and 48 teeth of stator (tooth pitch 7.5º). So there is 0.3º gap between tooth of rotor and stator. When A-phase becomes magnetization, the nearest teeth of the rotator at the next B-phase from teeth of the matched rotator is 7th. So angle difference between A and B phase magnetization is (7.5º - 7.2º) * 6 = 1.8º. So step angle of basic revolution is 1.8º.