Using the list below explain a) why must the enamel insulation be removed off of
ID: 2008088 • Letter: U
Question
Using the list below explaina) why must the enamel insulation be removed off of one end of the rotor wire, but only off of one side of the wire on the other end?
b) What happens when the exposed part of the rotor wire is in contact with the copper rotor support? What happens when the insulated part of the rotor wire is in contact with the copper rotor support?
c) What would happen if all of the enamel insulation were removed off of both ends of the wire?
D-cell battery
#12 gauge bare solid copper wire
#24 or #25 gauge enamel-coated magnet wire
Strong ceramic magnet
Rubber bands
3-inch long wooden dowel of 1-inch diameter
3-inch long wooden dowel of ¼-inch diameter
Explanation / Answer
This is a great motor. a) one side we want to have electrical contact all the time, so we take all of the coating off. The other side we want it to have current flowing to create a magnetic field through the coil to attract the magnet until it is near the magnet and then stop being attracted so that there is no force and it can keep rotating. This is also true if we flip the magnet over; we want it to repell until it is as far away as it can get and then stop the magnetic force and let the angular momentum swing the coil around again a half rotation. b) current flows when the exposed side is in contact. This current sets up a magnetic field. The coil is an electro magnet. When the insulated part is in contact with the copper support, no current flows. c) If the insulation were removed the electromagnet would always attract the permanent magnet (or always repell), so the coil would spin a half turn at the most and then stay there. To spin, there needs to be an attraction (or repulsion) for half of the rotation and then no force for the second half of the rotation. If there is always attraction, the magnet would pull the coil but never let it go. If there is always repulsion, the magnet would always push the coil away. To spin, more complicated motors push and then pull to get the coil to spin. This one pushes and then let's it coast, or pulls and then let's it coast (depending on the coil direction and the magnet).
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