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G2 motor controller. Switch to manual DC power

#1

Hi,

I am using a polulu G2 high power motor driver 18x18 to control a DC motor. I am controlling the system with an arduino and powering the system with a 24V switching power supply.

Now I want to add a DC switch in my design that allows me to switch between powering the motor controller and powering the DC motor directly. So effectively if I flip the switch, the motor controller is powered down and the DC motor is directly connected to the power supply (with some manual control button in between to turn it on or of). I have attached a simple drawing to illustrate.

My question is: if I flip the switch, the motor will be powered directly, but the M1A and M1B ports of the motor controller will also be directly connected to the 24V from the power supply. Will this be a problem? Can the board handle this?

Thanks

#2

Hello.

It would likely destroy the driver if you connected the motor output pins to 24V while the motor shield is powered off. Why do you want to power the motor directly? You could use a switch with extra poles so you can disconnect the driver outputs from the motor as well.

-Tony

#3

Thank you,

I am using the motor controller for a dual axis solar tracker. I would like to have the option to control de tracker manually when needed. The extra poles is then the way to go, but I wanted to check if it would be necessary.

Out of curiosity, would you know why the driver will be destroyed if I connect the output pins to 24V. What would cause the driver to fail.

Thanks

#4

Hello.

The maximum rating on those pins is VIN + 1.2V, so 24V on those pins while VIN is 0V is way above those ratings.

-Tony

#5

Thanks, much appreciated!

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