Synchronous inductor motors identical in construction to PM-type stepping motors are widely used in chart paper drive and other applications owing to their characteristics of constant speed in a low speed range and excellent start/stop performance. This type of motor is usually driven from single phase source with a phase-shift capacitor.
This paper discusses some methods for choosing phase-shift capacitor. The influence of capacitor value on motor characteristics is being investigated showing that there exists specific values of capacitor for making pull-out torque maximum and alternating torque minimum.
Based on these results, three criteria to determine the value of capacitor are presented.These are;
1) Minimum alterating torque.
2) Maximum pull-out torque.
3) π/2 phase difference between main and auxiliary phase currents at standstill.
A comparison is achieved between pull-out torque, alternating torque, and starting characteristics under the above three conditions.
As a result, “minimum alternating torque condition” is recommended for proper choice of capacitor value for the normal use of inductor motors.
抄録全体を表示