Powering 2 Large 12V DC to AF Motor Shield & Arduino

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davis425
 
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Powering 2 Large 12V DC to AF Motor Shield & Arduino

Post by davis425 »

Hello,

I am having an issue trying to power and run two large DC motors using the Adafruit Motor Shield and Arduino. I have a workbench power supply set with a max voltage to 11.5 volts and 0.5 amps. Motors were connected to M1 and M2 on the board however when I run the program and expect to see both motors run at a high speed the voltage immediately drops to around 2, both motors barely spin, and just stop.

If I run only one motor from this power supply everything is fine. I know I am likely doing something wrong but I can't find the appropriate information for how to power this. Do I need two power supplies? One for each motor? Do I need to set my max volts to around 24V on my power supply and increase amps from 0.5 to 1?

Any help will be greatly appreciated.

Regards - Dave
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adafruit_support_bill
 
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Re: Powering 2 Large 12V DC to AF Motor Shield & Arduino

Post by adafruit_support_bill »

Those motors are attempting to pull much more current than your power supply can deliver. According to the data sheet for that motor, it pulls 400mA at 12v. Since your power supply only provides 500mA, the voltage will sag when you attempt to pull 800mA from it.

https://handsontec.com/dataspecs/motor_ ... -Motor.pdf

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davis425
 
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Re: Powering 2 Large 12V DC to AF Motor Shield & Arduino

Post by davis425 »

Thank you for your response. Should I change my settings on my workbench power supply to provide at least 800mA or 1A and leave the voltage as is around 12?

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adafruit_support_bill
 
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Re: Powering 2 Large 12V DC to AF Motor Shield & Arduino

Post by adafruit_support_bill »

If your motors run fine individually at 500mA, increasing the supply limit to 800 or 1000mA 1A should be fine.

The motor specs for the XD-3420 are fairly vague and do not specify what conditions the 400mA figure correspond to. The current demands of a DC motor are not constant. And peak demands can be many times the 'no load' current draw.

The TB6612 driver chips on the motor shield are rated for a maximum of 1.2A continuous. If this is exceeded for more than a couple of milliseconds, the chip can be permanently damaged. Limiting the overall current to that level or less will avoid possible damage in the event that the motors encounter a stall condition.

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davis425
 
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Re: Powering 2 Large 12V DC to AF Motor Shield & Arduino

Post by davis425 »

Thank you! This was very helpful.

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