Multipole stepping motor for clock - includes disc rotor with number of pole pieces selected to give good starting when current is applied

摘要

The motor includes a rotor in the form of a disc turning in a first plane. A stator is formed by pole pieces (1, 2) arranged in a second plane. In addition there is a magnetic core (3) and a winding (4) formed around the core. The rotor has a number of poles which is equal to a sub-multiple of the number of steps to be made in one turn of the motor. The distribution of the normal rotor induction is such that there is a fundamental pattern with 2p poles and a clear 3rd order harmonic comprising 60 poles. ADVANTAGE - Motor has good starting characteristics.