Harold E. Edgerton uses a stroboscope and high-speed photography to illustrate the behavior of a synchronous motor. He applies different strobe light speeds to observe the running motor apparently slowing down, standing still or speeding up. Title cards explain what is being shown as the strobe light is adjusted to show how the motor slips and then is pulled back into step to obtain synchronism. This film demonstrates one of the practical applications for which Edgerton first devised his stroboscopic equipment in the early 1930s.

TIME CODE	DESCRIPTION
00:00:01	Introductory information: film title, synopsis, date, run time.
00:00:08	Film begins.
00:00:10	[Title card] “SYNCHRONOUS MOTOR MOTIONAL TRANSIENTS, Massachusetts Institute of Technology”
00:00:18	[Title card] “A 160 h.p. synchronous motor is directly coupled to a generator, with stroboscope tubes arranged for observation of rotor.”
00:00:26	The motor is shown; revolutions stop.
00:00:32	[Title card] “The motor is brought up to speed.”
00:00:37	A man in glasses pulls a lever to start up the motor.
00:00:40	Close-up shows a marker above the rotating wheel marked “N “ and “S;” as its speed changes, the letters appear to speed up or slow down.
00:00:50	[Title card] “It ‘pulls in’ as a reluctance motor.”
00:00:56	Close-up of the rotating motor is shown as the speed is adjusted so that the letter “N” appears to be stationary.
00:01:04	[Title card] “With load applied and no field, the rotor slips.”
00:01:10	Close-up of the rotating motor shown.
00:01:15	[Title card] “The field switch is closed and the loaded machine pulls into step.”
00:01:21	The man at the controls presses a lever upwards.
00:01:25	Close-up of the rotating motor is shown as the speed is adjusted so that the letter “N” appears to be stationary.
00:01:32	[Title card] “Full voltage applied to stator.”
00:01:37	The man at the controls pulls two levers.
00:01:41	Close-up of the rotating motor is shown as the speed is adjusted so that the letter “N” appears to be stationary.
00:01:44	[Title card] “Switching field on at a favorable angle, machine pulls into step. (3 cases shown)”
00:01:54	Close-up of the rotating motor is shown as the speed is adjusted in various ways to achieve synchronism.
00:02:20	[Title card] “At an unfavorable angle, and load above critical value, synchronism is not obtained (2 cases)”
00:02:27	Close-up of the rotating motor is shown as the speed is adjusted in various ways: synchronism is not achieved.
00:02:41	[Title card] “By careful adjustment, an intermediate case is obtained.”
00:02:45	Another rotating motor is adjusted so that intermediate phases can be achieved.
00:03:36	Film ends.
00:03:42	© 2010 MIT credits.

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