This 1961 U.S. Army training film covers the basic physics behind the function of DC motors and generators. This is demonstrated through progressively more complex animations that discuss the basics, such as the generation of electromotive force, the necessity of adding armatures and commutators, the need to add brushes, and necessary adjustments that need to be made to the neutral plane to avoid sparking which can damage the generator. Generators and motors are at the basis of most machines from simple things like field telephones to missile engines, so an understanding of them is essential for all engineers.
0:06 Title “The U.S Army Presents: Motors and Generators: Part 1 DC Motors and Generators”, 0:51 a missile launching out of a silo, 1:03 an AC and a DC motor next to each other, 1:23 hand demonstration of an electro-motive force, 1:56 animation demonstrating the effect of electro-motive force on voltage, 2:58 animation of a more practical EMF generator through a rotating device with current flow shown, 4:09 EMF equation shown as the animation continues running, 6:17 Animation showing and demonstrating the new equation needed for the calculation of EMF with a rotating conductor, 6:57 animation showing EMF during one revolution of the conductor, 7:28 Animation of AC generator turned into a DC generator through the addition of a commutator, 8:18 graphical representation of the output EMF creating a pulsating direct current, 9:00 attempts to smoothen the ripple of the DC pulses through the addition of magnets, 9:42 demonstration of the armature on actual DC generators, 10:25 animation of brushes placed on the neutral plane to avoid sparking, 11:14 demonstration of armature reaction, 11:37 demonstration of how to avoid sparking by 1. Adjusting the brush position or 2. Adding inter poles, 13:31 Different Iron core inductors demonstrated in a diagram of electric current flow, 15:01 demonstrations of effect of an increase in load on different types of generators, 16:39 Graphic representation looking at terminal voltage and armature current for different generators, 17:24 US Army engineer connects an electric source to DC generator to create a DC motor, 17:58 hand demonstration of a motor, 18:51 animation of an electrically charged conductor moving in a magnetic field for both positive and negative charge, 20:36 demonstration of conductor with armature and a voltage applied moving in a magnetic field, 21:54 animation of the neutral plane in the motor depending on different loads, 22:20 demonstration of how to avoid sparking by again adjusting the brush position or adding inter pole fields, 23:34 animation of the effects of counter electromotive force (CEMF), 24:31 a DC motor starting box, 24:47 animation of how a starting box functions, 25:58 animation of torque in different types of generators such as a series wound, shunt wound, or compound wound motor, 28:50 summary of what has been covered so far such as how EMF is generated in AC and DC generators and what the different type of generators are, 33:45 a missile taking off
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This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit http://www.PeriscopeFilm.com
