Interior

• Tile Installation
  Last year, for torque measurement, the motor was attached to a speed reducer. One end of the piece of thread was affixed to the axle of the speed reducer, while the other end contained a hook, which was holding a box. As the motor spun, the thread was slowly winding onto an axle. This lifted the box. The speed reducer ratio was approximately 1:150, which means that the motor needed to make 150 revolutions to make the axle rotate one turn. The box that was lifted contained a specific number of weights, which were actually ceramic tiles. Three ceramic tiles weighed exactly 1 lb. To achieve 0.5 lb. increments, one tile was split in half. The picture below shows also a regulated power supply (in the upper right corner) and the electronic counter (on the right side).

General

• Insulation
  Most of the motors worked. Here are the reasons why some of them didn’t work: Some of the girls weren’t careful enough when they aligned the rotor on the stands, so they had too much friction. A few of them got their wire tangled when they were winding the electromagnet, but they were tired of winding and didn’t want to start over, so their electromagnet wasn’t strong enough. They broke a few reed switches bending them too sharply (but we had plenty). And a few motors didn’t work because the girls hadn’t removed enough of the insulation from the lead wires to make the connections. (This one was easy to fix once the problem was found). Quite a few of them didn’t understand why they had to figure out which way to connect the circuit to get the magnets to repel. In some ways this was good, because when I was helping them fix the motor, I could explain more to them about how the motor worked. We talked the beginning before they started to put their motors together about how motors worked, but it went too quickly for them all to understand.”