Motor Test Report 30 
Horsepower Single-Phase Written-Pole^®  Motor 
Page 3

This characteristic was particularly evident after a prolonged locked rotor test in which the rotor was locked for a period of three minutes with rated voltage applied to the terminals. An initial temperature of 55ºC was recorded at the start of the test (after performing 12 successive start tests over a period of 30 minutes). Upon completion of the test, the measured winding temperature was 107ºC, yielding a temperature rise of 52ºC. 

The prototype's peak starting current was recorded when the exciter was energized at approximately 1575 rpm. The peak current recorded during this period was approximately 168 amps with rater voltage applied to the motor terminals. This value represents a peak starting current of 1.7 per unit or 1.7 times the rated current of the motor, considerably less than conventional electric motors. A comparison with a conventional 7.5 hp single-phase capacitor Start/capacitor run motors chows a comparable starting current.