# What happens if a motor wants more constant current then the VESC can handle?

Lets take an old vesc 4.12 as example. peak current is something about 240A as far as i remember and constant current is 50A.

what would happen if (for whatever reason) the motor wants more then 50A over a longer time. will the VESC limit it by itself or will is just burn out sooner or later?

the motor does not want. the vesc always give. itÂ´s all up to the settings you put in the vesc while setup.

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i am fairly certain that a motor â€śdrawsâ€ť current! you are talking about voltage. Otherwhise the current protection boards on stepper drivers wont make much sense. its just there to protect the driver from more current then it can handle. and a stepper motor is pretty much the same thing like a phases motor, just has more phases. and loading a motor results in more current use. thats even true for dc motors hooked up directly to a powersource.

edit: Electroboom video proof: https://youtu.be/yO9xIVv8ryc?t=400

You can draw more than 50A but not for a long time. Like @Andy87 said itâ€™s all about the settings like motor max and batt max.

BTW 50A cont. from battery is not realistic, above 27A the vesc 4.12 gets hot, but donâ€™t mix this with motor amps.

And no the vesc wonâ€™t burn because of the temp cutoffs.

Eh sort of, a motor has windings in it that are just wires with a set resistance if you apply a voltage (charge potential difference) to each end of the wire then current flows through it. How much voltage is applied is controlled by the VESC in this case by opening/closing the gates of the MOSFETs. Vid there is referencing brushed DC motors which work differently from Brushless DC (BLDC) motors.

A DC motor with a set resistance will have a set current flow through it given the same voltage, and so will â€śdrawâ€ť or use a certain amount of power (Watts, amps times volts) at a given voltage. The VESC or any sort of speed controller adjusts the voltage applied to the motor and in the case of Brushless DC which coils are energized to get/keep the motor spinning.

perfect, that was pretty much what i was looking for.

PS: i know that it is unrealistic, but i am a sucker for details, whats why im asking.

i see coils and magnets and some mechanic (the brushes) that powering individual coils to make the motor spin by creating magnetic fields. so the only thing different is the ESC which handles the â€śbrushâ€ť part. care to elaborate where that is different? from a physics stanndpoint i mean.

Yah didnâ€™t mean to say they are electrically much different, just that the video is explaining a different kind of motor from the ones weâ€™re typically using. Any coil with current going through it is going to act as a solenoid, guess the major differences with BLDC vs brushed DC are the greater efficiency of BLDC and faster switching rate for given RPM needed for smooth operation of BLDC motors.

yes a motor draw currentâ€¦ but if your current draw is limited by the vesc softwareâ€¦ how ever, i think you got your answer anyway.

The principal of operation of brushed motors and bldc motors is very different.

Brushed DC motors, you just apply voltage (with 2 wires) and they go. The rotation of the motor physically determines which brushes are in contact with which coils. No control electronics are required. As you said, the motors draw power.

BLDC motors on the other hand have 3 phases, and applying DC voltage to them will do nothing. They need a smart controller to feed power to the 3 phases in a very specific way. This speed controller will have pretty much total control over the power the motor can use. The default mode in vesc is called â€ścurrent controlâ€ť, and thatâ€™s exacly what it does.