Fans of Motor Heatsink problem

Many fans of motor heatsink was take power from Receiver.
If the fans was damage , malfunction or short circuit. Is it the receiver or ESC will burn ?

I have try a 5V fans for my motor heatsink . I found that the fans speed have different when use different  throttle. Is it normal ?

I have burn 2 pcs. of ESC and don't know the reason at before....
(Firstly , the esc is work normal , and then I put down the RC to take a rest (no power off the esc) .... 5 mins later.. the motor of RC start automatically. The fans of heatsink stopped. Problem occur .. The ESC power button malfunction. (Press ON or OFF... the ESC still have power)... I press the Full reverse.... The ESC burn....) Both ESC burn in the same problem.

Anyone know ?

Thanks.