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how to choose the proper power supply to ESC? Answered

hello , it's my first time posting here and i hope i have help

i have a brushless motor with ESC rated as 30 A max

i tried to connect it to a 12V- 125 A power supply but the ESC was burnt

i wonder why did this happen ? i was told that the ESC will take the current it needs from the power supply and there are no problem to connect them together

can anyone explain what happened to me?


brushless motors tend to be rated by the number of (LIPO) cells they can handle - 2 or 3 possibly up to 6 cells. Each cell will fully charged be about 4.4 volts and fully discharged about 3.3 volts, so a 2 cell battery will give you 8.8 volts to 6.6 volts.

Your ESC should have also had a max rating on it in terms of cells .

Were you connecting the ESC the right way round, was the motor connected?

I am sorry but you need to tell us more.



i put links above for the specifications for both the motor and ESC

my friend told me he connected it before with the power supply and it was fine

the power supply gives 12 V which the motor and ESC need but the current rated on the power supply is too high

its 125 A and the maximum current is 30 for the ESC and i was told that the ESC will take the current it needs from the power supply and not all the 125 A will go into the ESC like what happened and burn it

also no signal was given to the ESC when this happened , just connected it and then it gave me smoke

Your ESC needs to be rated at least 150% of the motor current. NOT just over!

The voltage is important BUT the current as you say will be what ever the ESC and Motor require if available.

In this case you over loaded the ESC - You need an ESC of 50 Amps or bigger.


Thanks a lot that's what i needed exactly , this site is great ;)

I agree - I have built several of their scratch build models and they fly really well. I have also designed my own versions and some of them flew as well !!


3 years ago

The motor appears to be a 3 phase winding ( 3 wires ) and it expects to receive a 3 phase step wave AC Power from the ESC 30A ( Speed Controller ) module.

If you simply placed 12V DC across any of the motor wires as you describe there is no rotating magnetic force just a coil winding acting as low order resistor that gets hot very fast and burns the magnet wire insulation and epoxy holding the coil wires in place.

This heat causes the smoking you are describing.

Sorry, but your motor is totally destroyed !


Another situation if you wired the module but left the small Blk-Org-Yel wires floating without the proper digital signals then it is possible the module put power to a motor coil and never switched to the next step position and the coil eventually overheated and the heat damaged the motor as my previous comment.

i didnt connect the power supply directly to the motor it was connected to the ESC which was burnt

The pic shows how the ESC power components ( probably MOSFETs ) deliver stepwise AC to a motor.

As you can see there is a path that can damage the ESC

Especially if there is no signal is available to control the A,a B,b C,c


What are all the specs of the motor? Is it a 12V motor?