Non-Simultaneous Reclosing Air-Gap Transient Torque of Induction Motor: Part II, Sample Studies and Discussion on Reclosing of ANSI C50.41

Using the analytical method derived in Part I, this paper shows the variations of air-gap reclosing transient torques caused by (1), the initial angle of system phase voltage waveform at switching off, (2), the dead time (i.e. time interval between switching off and reclosing), (3), the delay of the reclosing of the third switch pole, (4), the value of the slip and (5), the parameters of the motor and capacitors. Examination of the resultant p.u. voltages per hertz calculated at the instants either before the reclosing of the two switch poles or of the third switch pole does not indicate that the limit of 1.33 recommended by ANSI C50.41 has real meaning in limiting the magnitude of the peak value of the reclosing transient torque. It is recommended that one calculate the reclosing torque using the method given in Part I instead of judging the reliability by rule of thumb. Good agreement was obtained between calculated and test results.