Physics
HS/Science
Unit: 10 Lesson 01
Generator Design Lab
Laboratory Partners:_________________________________
Introduction:
This lab activity utilizes simulations to examine the important parameters in the design of an
electrical generator. The terminology of motors and generators is developed, and the equation for
a simple generator is presented in terms of the generator parameters.
Vocabulary:
armature, coil, frequency, angular frequency, commutator, amplitude, flux, waveform, brush
Procedure:
Part A: Rotating Magnet Armature
1. Open the simulation “Faraday’s Electromagnetic Lab", and select the generator tab. Set
controls similar to those in the diagram at the right.
http://phet.colorado.edu/en/simulation/faraday
2. Investigate how (or if) the variables below affect the size of the voltage induced in the coil. The
coil and rotating magnet represent a generator design.
3. Summarize your observations and conclusions in a Word document:
• Number of turns in the coil
• Strength of the magnet
• Speed (frequency) at which the magnet rotates
o Is the output ac or dc?
• Area of the coil
• Orientation of the magnet and sign of the induced voltage
Part B: Rotating Coil Armature – ac Generator
1. Open the Walter Fendt applet, and set the generator
up as shown in the diagram at the right. The URL for
this simulation is:
http://www.walter-fendt.de/ph14e/generator_e.htm .
2. Investigate how (or if) the variables below interact
and influence the size of the induced voltage.
3. Summarize your observations and conclusions in a Word document:
• Angular rotational speed of the coil
• The orientation of the coil related to the voltage output and the graph of voltage vs. time
• Note how the electrical contact is made, keeping the wires from twisting.
• The term “cutting lines of flux" is sometimes used; relate the cutting of B lines in
relationship to the amplitude of the voltage.
• Locate the spot (orientation) in the rotation where no current is generated.
©2012, TESCCC
11/07/12
page 1 of 2
Physics
HS/Science
Unit: 10 Lesson 01
Part C: Rotating Coil Armature – dc Generator
1. Using the Walter Fendt simulation above, change the configuration of the generator to have a
split ring commutator.
2. Investigate how (or if) the variables below interact and influence the size of the induced
voltage.
3. Summarize your observation and conclusions in a Word document:
• Angular rotational speed of the coil
• The orientation of the coil related to the voltage output and the graph of voltage vs. time
• Note how the electrical contact is made to keeping the wires from twisting. How does the
commutator convert the ac voltage into dc voltage?
• Is the output voltage dc? Is it constant dc such as from a battery?
*Part D (Optional): Examine a Toy Motor/Generator
1. If you have a toy motor, similar to the one in the student generator, disassemble that motor to
determine if the magnet rotates or if the coil rotates.
• Summarize your findings in the student report. Indicate if the coil or magnet rotates, what
kind of commutator is present, and if there is more than one winding orientation.
The student report for this lab consists of the following:
• This handout with notes and worked out problem
• A Word document with summary paragraphs for parts A, B, C, and D
• One report per lab group is required; it should reflect the entire group’s efforts.
©2012, TESCCC
11/07/12
page 2 of 2