What happens to an electric motor if it over heats?

you generally get insulation failure

this is why older motors with cotton wrapped windings are much larger an more efficient than newer ones with hi temp epoxy paint on the copper

the cotton has severe problems if the winding temperature reaches 250F where the epoxy can survive 500 or so

there are some made with silicone and fiberglass which can go to perhaps 800 before burnout

this is what is known as false economy

for more horsepower you can opt for more power input but you generate more heat than torque

you see the race cars with nitrated fuels where the normal 300Hp engines put out 1200Hp or so but they must be rebuilt after every 4second 1/4 mile race

you can do the same thing with electric motors and lots of extra cooling

so a 10HP motor can probably run at 15hp output for some time with an additional 10hp cooling fan if the windings dont get hot enough for insulation to fail