Eli5 What causes motors to overheat when it’s facing more resistances than it can handle?
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What kind of motor? Do you mean electrical or frictional resistance? If frictional the metal will bond itself together due to the heat.
The motor windings are designed to allow a certain number of electrons through per unit of time.
Exceed this number and energy will be lost as heat.
Significantly exceed this number and the windings will burn causing irreparable damage.
Motors work through electromagnetic induction – a charging electric field inducing a changing magnetic field. But that principle happens in reverse too – a changing magnetic field induces an electric field, and as the motor is spinning, the coils moving through a magnetic field induces an electric field that opposes that of the power source and impedes the flow of current. The coils themselves in the motor have fairly little innate resistance.
So the motor is somewhat self-regulating, if it is connected to a heavier mechanical load and it starts to slow down, then the “back-EMF” gets weaker and its power draw increases. If the rotor is held in place while the motor is powered on, and it cannot overcome the load to start spinning at all, then there is very little electrical resistance and it can draw huge currents, enough to heat up the coils and potentially burn out the motor
The electrical energy going into the motor must go somewhere. If the motor is functioning normally, most of it becomes kinetic energy. But if the motor unable to rotate due to too much load, the energy cannot become kinetic energy, so it becomes heat instead.
For electric motors, you push power through the motor to make it turn, but the power you out in doesn’t equal the power that comes out. This happens because it takes a bit of power to push the rest of the power through the copper.
Where does this power loss go? Most of it becomes heat. So what happens when you stop the motor from turning all together? You’re still pushing power through the motor, but none of it is coming out. So all of it is turned into heat.
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