I have trex 450 witch I built and fly. I am setting up a 450 coptorx. I have coptorx electronics and the ESC has a electronic device between it and the reciever. Not sure what its purpose is, im guessing to stop interferece with the reciever? Anyway this unit is getting hot after a little while when on.Im still setting up so I dont have the motor pluged in at this point. What is this unit for? Is It bad becouse its getting hot? Is not having the motor pluged in causing it to get hot? please if any one can help I would appreciate it Thanks Jeff

that is you bec - battery eliminator circuit
it is best to use a separate flight pack battery pack to set up your servo"s
and pitch values then plug in you heli battery and speed control to set up the speed controller
you could burn your bec and speed control up using it to setup your servo"s
because its a linier bec. if you use a flight pack to set your heli up do not have the speed control or bec hooked up yo your receiver.
hope this helps

hay thanks for your post. I allready had a flight pack charged to do just that, Im worried about it burning up in flight. It gets hot in only 5 to 10 min, flight time should be 6 to 8 min.Not sure what a linier bec means?I guess what im asking is should it behave differently when flying compared to set up? Thanks Jeff

i have read that that esc and motor does get a little hot in flight.
here is a good place to read .
http://www.rcgroups.com/mini-helis-374/
and
http://www.helifreak.com/