Code Number: 5K10.82
Demo Title: Homopolar Motor as a Generator
Condition: Excellent
Principle: Motors & Generators
Area of Study: Electricity & Magnetism
Equipment:
Homopolar Motor Unit and Roller with internal magnets, Large Gray Lecture Galvanometer or the Large Older (Ancient) Black Lecture Galvanometer.
Procedure:
See: 5H40.53 - Homopolar Motor and 5H40.38 - Lorentz Force With a Twist demonstrations.
Connect the Unit to the gray or ancient black lecture galvanometers. ( These two have the best sensitivity for this demonstration ). Slide the copper pipe containing the two cylindrical magnets on the rails and notice that there is little to no deflection of the galvanometer pointer. Now roll the copper pipe on the rails and note the observed deflection of the galvanometer pointer. The TPT, Vol. 36, #8, Nov. 1998, p. 474 article explains this behavior very well.
References:
- Keith Zengel, "The Handheld and Hand-Powered Homopolar Generator", TPT, Vol. 56, #1, Jan. 2018, p. 61.
- H. K. Wong, "Motional Mechanisms of Homopolar Motors & Rollers", TPT, Vol. 47, #7, Oct. 2009, p. 463.
- Norihiro Sugimoto and Hideo Kawada, "The Homopolar Motor and Its Evolution", TPT, Vol. 44, #5, May 2006, p. 313.
- Robert Beck Clark, "The Simplest Generator from the Simplest Motor?", TPT, Vol. 44, #2, Feb. 2006, p. 121.
- Bill Layton, Martin Simon, "A Different Twist on the Lorentz Force and Faraday's Law", TPT, Vol. 36, # 8, Nov. 1998, p. 474.
- Jorge Guala-Valverde, Pedro Mazzoni, and Ricardo Achilles, "The Homopolar Motor: A True Relativistic Engine", AJP, Vol. 70, #10, Oct. 2002, p. 1052.
- Robert D. Eagleton and Martin N. Kaplan, "The Radial Magnetic Field Homopolar Motor", AJP, Vol. 56, #9, Sept. 1988, p. 858.
- Robert D. Eagleton, "Two Laboratory Experiments Involving the Homopolar Generator", AJP, Vol. 55, #7, July 1987, p. 621.
- J. Fukai, "Magnetic Wheel Unipolar Motor", AJP, Vol. 45, #11, Nov. 1977, p. 1128.