Analysis of Alternating Torque Characteristics of 2-Phase Servomotor under Lissajous Field

Abstract

When two source voltages with different frequencies supply to a 2-phase servomotor, we can utilize this situation as a convenient way of phase modulation for studying the motor's frequency respose characteristics.
In this paper, an equation is derived for calculating the alternating torque of a 2-phase servomotor which is operated with a 2-phase source unbalanced in frequency.
Its equation is expressed by the equivalent circuit parameters applying the concept of the starting torque of an induction motor to this condition.
The alternating torque characteristics with the additive and subtractive componets of the source frequency are discussed numerically and the generating ratio is considered.
The calculated value is comparad with the experimental one by using a 2-phase induction type accelerometer.
The agreement is satisfactory.