motor destroys esc

[carpenterdean]

Hi guys, novak motor in my sons car today ended up destroying lrp esc for some reason it generated so much heat it actually melted part of the battery casing, everything was hot including battery, however the battery is still working, i connected a different esc and gave it another try again noticed small amount of smoke so unplugged quick, after just a few revs on the throttle the motor was really hot, what i did notice is that when i throttled up the led light on the pt went dim, put new motor on and all worked well, so obviously a motor problem.
Now i'm home took ends off the motor nothing very obvious to me all free moving just noticed what seemed to be a couple of small bits of solder dropped out?
Any idea's whats happened to the motor?
Thanks.