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I found a rock lodged between the fan and the radiator on my motorcycle. Now the fan does not work when the computer prompts it to. I tried directly attaching the 12 volt battery to it as well. No luck. My assumption is the motor was unable to overcome the friction and spin, thus getting too hot and 'burning out', but what exactly burned out here? I have some pictures attached to show you. Now to my understanding if this motor had winding that were intertwined, the actual copper would melt and cause an open circuit, which then would cause the issue. Now this DC motor looks a little different so this is why i'm confused as to why it stopped working. When I took it apart there was no physical damage to it. I've checked for continuity between all wires and everything checks out. So does copper lose some of its properties when super-heated, thus causing the magnets to stop spinning it? I'm really wondering what caused this motor to stop running. I can't seem to find anything wrong. Also, when it's put together there is very little resistance for it to spin freely. Electricity is flowing, or so it seems anyway. Theses are the windings? The copper sits on top of the magnet here.

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closed as off-topic by rob, ACuriousMind, Martin, John Rennie, David Z Apr 25 '16 at 12:08

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Your reasoning goes astray when you speculate that overheating would cause an open circuit. The insulation melts before the copper, causing a short across many of the coil wraps. This reduces the strength of the electromagnet dramatically, causing the motor to not move.

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  • $\begingroup$ True, but look at the copper plate. Nothing appears to be wrong with it. $\endgroup$ – Cody Terry Apr 25 '16 at 0:12
  • $\begingroup$ @CodyTerry: I can easily see the discoloration on the wire. That's usually a sign that something went wrong. You could measure the resistance and inductance of the winding and compare to a good one, that would be the telltale measurement. $\endgroup$ – CuriousOne Apr 25 '16 at 0:42
  • $\begingroup$ I've already ordered another one. Still curious as to why the old one doesn't work. Yes, I didn't note the discoloration. $\endgroup$ – Cody Terry Apr 25 '16 at 3:01
  • $\begingroup$ The insulation on coil wire is very thin. It often just looks like an oily film on the wires. Visual signs of damage can be very subtle. $\endgroup$ – Duncan Harris Apr 25 '16 at 3:05
  • $\begingroup$ Can somebody explain how, under normal conditions, this little motor works? What exactly do those rectangular prisms do that are located towards the top of the second picture? There are two of them. I know they conduct electricity. I've seen them on other electronic devices too. If possible i'd like just an overview of this thing. I thought I understood it but maybe not so much after all. $\endgroup$ – Cody Terry Apr 25 '16 at 12:03

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