DC motor with encoder as brake and transport system. Voltage kickback?

Other Hardware General Electronics
1

Hi there,

I am working on a rc rollercoaster system and currently thinking about hill lift and braking system.
I don’t want to have the track itself electrified, but the wagons are equipped with a battery and a microcontroller.
For hill lift, I was thinking about a fixed gear rack on the track underneath the wagon and a motor with a gearwheel on the first wagon, that pulls the train along the gear rack (the microcontroller gets the Information to spin the motor from magnetic elements on the track by the use of a micro reed sensor).

However, I want to use the same system for braking as well. I was thinking about using a motor with encoder. When the train gets the signal to brake, I would sense the current rotational speed of the motor, spin it at the same speed and then slow down the speed by motor control until the train stops.

I am now worried about the kickback voltage from the motor when the train runs into an braking area and the motor will at first be rotated manually.
I thought about using a Schottky diode, but then the kickback is likely to destroy the encoder electronics inside the motor, because the diode would be connected after the motor.

Am I right here, or did I get anything wrong? Do you have any oder ideas for using the same system for braking? As you may anticipate, there’s very less space on the wagon, so I try to reduce the total component count :slight_smile:

2

I doubt very much that your motor speed control has that ability. Testing is necessary before you depend on it.

3

You need a controller that has "Dynamic Braking".

4

Yes, I’ve read a lot about dynamic braking after I did the post. Thank you for the feedback!

Do you have any suggestions for a small one? All of the ESCs I know that have a braking feature can only stop with full force, like shorting the motor pins.
Do you think it would be possible to build something by myself with a dpot acting as a rheostat?

5

Do some research on "electric vehicle drive motors and controllers" google will give you a lot of leads. The regrettable breaking just dumps the energy as heat but you could also use that to charge the battery but that is a lot more complicated.

6

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