How to let a motor run without braking it when applying 0 pwn

Projects General Guidance
1

Hello,
I would like to know if it's possible to make a motor run until a desired speed and when this targeted speed is hit, stop power the motor and just let it run.

When I directly power the motor and cut the power supply, the inertia of my steel cylinder allows the whole thing to turn for a long time. When I use a motor controller ( Cytron MD10C R3) to bring the motor to speed with the arduino and then send 0 pwn when I get the speed I wanted, the motor brakes..

I would like to know if there's a way to power the motor with an arduino to the deisired speed and then let it run without the motor brake.

Here's the assembly (the H bridge wasn't mounted at the time):

IMG_20220128_164501
IMG_20220128_1645011920×1440 192 KB

The whole purpose is to then brake the cylinder with a brake disk so if the motor itself brakes the whole system it looses its purpose...

It might not be super clear so if you need any more information please ask!

Thanks in advance

2

If I understood correctly, you want the motor to freewheel once the target speed is reached (when PWM is set to zero), right?

I guess its the motor driver that is causing it to brake (it is using the zero PWM to bring motor to zero speed) - so what you need is to look for a way to completely disconnect the motor from the driver, or disabling the driver itself when the target speed is reached instead of setting the PWM input to zero, so its not applying any current to the motor.

3

Yep exactly

I tried looking up solutions but a part from manually disconnecting the controller or turning off the power supply, I don't see a solution with an arduino and no exterior intervention..

But thanks for the solution nonetheless

4

Connect a relay with the main motor supply (including driver) - activated from arduino.

Steps to do: Relay on, spool up to speed with increasing PWM, relay off, PWM zero (for next iteration)

5

You need to use a H-bridge to drive the motor and use the PWM to drive then enable pin of the H-bridge. When you want to stop the motor, assuming that the H-bridge has a zero to enable it, you write a one to it to disable it and put it into free running mode.

6

Should work like a charm thx

7

You're welcome. Glad to help.

8

Get a better driver, this one cannot let the motor "coast".
If you don't need bidirectional driver single transistor (or relay) and a freewheel diode is all you need.

9

That will work as well - no need for an external relay.

10

There doesn't seem to be any pins available to do that on my model..

11

Corrrect.

13

Then use the relay method or get a driver that has an enable pin. Though with the relay there will be zero current draw for the period it is switched off.

14

So what model of H-bridge do you have and how have you wired it up?

1 Like
15

wired up to the motor, power supply and arduino

1 Like
16

Wow the detail in that reply is just staggering.

Looks like you chose the wrong motor driver if you wanted it to freewheel.

17

What did you want me to say... If you looked at the specsheet of the driver you would have seen that there are just the basic pins and so its like all other drivers...

Yep it seems that it is the issue..

18

I wanted a schematic of how each connection and the power and grounds were connected up.

19

Power +/- to generator
Pins A/B to motor
Pin ground to ground of arduino
Pin pwn to pin 5 of arduino
I only need my motor to turn in one direction so i don't use the "dir" pin of the driver

20

No a schematic not a wiring list. Never mind, lost the will to live.

1 Like
21

What's the point...
I love that you guys are very quick to answer and already have solved a lot of problems but if you just do this then you'll disgust people of arduino and they won't come back and try again...

Sorry i'm not taking 30 min to make a schematic for you.. There are not thousands of wires...
And moreover, we already acknowledged that the driver I'm using doesn't suit my project

Go be grumpy somewhere else..