Measurement and computation of starting torque pulsations of salient pole synchronous motors

• Published in: IEEE transactions on energy conversion Vol. 5; no. 1; pp. 176 - 182
• Main Authors: Ojo, J.O., Ostovic, V., Lipo, T.A., White, J.C.
• Format: Journal Article
• Language: English
• Published: IEEE 01.03.1990
• Subjects: Coils; Current measurement; Electric variables measurement; Electromagnetic measurements; Mechanical variables measurement; Power measurement; Synchronous motors; Torque measurement; Velocity measurement; Voltage
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/60.50829

Five basic methods of synchronous motor torque measurement are described. The first method is the traditional mechanical measurement using an accelerator; the second method involves an electrical technique using search coils as flux sensors; the remaining techniques employ either terminal voltage and current or input power and speed. Measurements of instantaneous electromagnetic torques of a medium-size 25 HP salient pole synchronous motor using these methods are compared with simulation results obtained from a full-order model as well as with a quasi-linear algebraic approximation. It is shown that torque measurement using search coils in the stator windings gives the best correlation with the simulation results, followed by a modified terminal measurement based on terminal voltage and current. The accelerometer method give the poorest results in that it is unable to capture the low-frequency components of the electromagnetic torques. It is also demonstrated by simulation that the approximate method for calculation of pulsating torques based on a quasi-linear model of the motor gives an estimate comparable to that of the full-order model, particularly for large machines.< >