BLDC motor without esc

brushless-dc-motormotor controller

I have an ESC and a brushless DC motor. I am interfacing the ESC to the motor. But I am not getting what I want, so my question is, can I directly connect the motor to the battery without taking the ESC into account?

Best Answer

No, you can't. A brushless DC motor is very similar to a three phase AC induction motor. You need to use a brushless DC motor controller (ESC) designed to generate the rotating field. A DC motor with brushes can indeed be run directly off of a battery (if it has a Permanent magnet field), as the rotating armature has a commutator to keep the armature developing torque against the fixed motor field.

A Brushless DC motor is, as I say, more like a three phase AC induction motor, except that the rotor doesn't turn by developing an induced current and magnetic field, rather the rotor has a permanent magnet which is driven by the rotating field. If you just apply DC to one of the 3 windings, all you would do is (possibly) move the rotor to align up with the magnetic field from that one winding, and then the winding would (most likely) burn up since it would appear as a dead short to the battery.

Also, most brushless DC motor controllers (ESC) are 'choppers' that limit the current sent to the motor, preventing thermal failure. So if you have a '12V' BLDC motor and connect it directly to a 12V battery (no ESC) not only won't it spin (as mentioned above), but I'd expect to permanently damage the windings. Since a stationary DC motor generates no back-EMF, the full battery voltage will be continuously passed over one resistive winding, generating lots of problematic heat.

Related Topic