To have overview I read the information at this link where braking is explained.

Now I deal with a motor where it is recommended with a large uF capacitor under the regeneration section.

The linear motor model I deal with is 72V DC.

I have two questions:

  1. For the linear motor to operate is this 72V DC converted to 3-phase AC?

  2. I'm recommended to install a capacitor across 72 V DC of this motor. Does that mean I'm adding a DC link capacitor? And in the first tutorial link it doesn't tell any benefit of the capacitor. What does such a large capacitor do regarding braking effect? What is that used for?

To be updated...


1 Answer 1

  1. Yes, it's likely that your motor controller converts the 72V to correctly phased AC drive to drive the motor.

  2. The motor while in motion will have kinetic energy. In order to slow or stop the motor, that energy has to go somewhere. You have the choice of burning it off in a resistor, using a mechanical brake, putting it back into the source voltage, or regenerating it into the line.

  3. By adding a large capacitor (yes, on the DC link) you are adding energy storage capability to your source which probably doesn't sink current. So you can absorb more energy without pumping up your 72V supply to the point where things fail. You should still have a resistive overvoltage clamp unless you can prove that you have enough capacitance to absorb the worst-case kinetic energy that the system can provide, but this is a more efficient approach than just using a resistor to dissipate the Ek.


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