By turning a coil by hand in a magnetic field to generate DC and AC. By supplying current to the coil to operate the device as a DC motor. Classes Used: Phys 102, 108
Combination generator/motor, DC Power supply, large magnet, projection voltmeter
The device has movable contact brushes which can be used on the slip-rings to produce an alternating output voltage to a voltmeter used on the overhead projector. The two contact brushes changed to the commutator will show the production of pulsating direct current when the handle is turned.
When both of the brushes are connected to the first joint : turn the handle, DC current is produced; Apply DC current of about 5 A, the motor will turn the handle.(PS: it needs a little push to start to rotate)
When one of the brush is connected to the middle joint and the other one is connected to the last joint : turn the handle, AC is produced; Apply 5 A of current, no apparent phenomenon will happen .
For all of these demonstrations, use a large magnet against the smaller magnet surrounding the coil (as shown). this avoids the complication of an electromagnet current being used to produce another current (in the case of using this as a generator), and allows us to use only one power supply in the motor case.
Updated on 10/Mar/2015
Demo room information