2x7A DC Motor Driver causing voltage drop

Help & Support Robot Parts
1

Hi,

I have given supply voltage of 13V, current drawn by motor is 2.5A and working voltage of motor is 12.5V. When motor is connected to motor driver, I can see voltage drop of 4V and the final output voltage is 9V, due to low voltage, motor is not moving. Is there any way to reduce the voltage drop?

And also could you please let me know what is the voltage drop @ 1A and @2A?

Thanks,
Bhavana.

2

Can you provide some additional information:

]Which controller are you using? Can you provide a link? What is its efficiency?/:m]
]What power supply are you using? What is the maximum discharge current?/:m]

3

Hi,

Thank you for your reply.

robotshop.com/en/2x7a-dc-mot … ifications.

Dc power supply. The maximum discharge current is 10A.

Thanks,
Bhavana.

4

When you measure the voltage at the terminals, it’s likely an average of the PWM signal. If you lower the signal, does the voltage drop further? Is there a chance that you are not providing the full signal to get 12.5V? What are you using to control it, and what is the signal being sent?

5

My ENA and ENB pins are connected to arduino 7 and 8 pins. I didnt set PWM speed. In my code, when ENA /ENB goes high i.e 1 ,Motor should move forward 100% and reverse 100%. I am following Control method which is mentioned in motor driver manual.

N1 IN2 ENA/ ENB Motor1/2 Behavior
0 0 x Stop (brake)
1 1 x Vacant
1 0 1 Forward 100%
0 1 1 Reverse 100%
1 0 PWM Forward at PWM speed
0 1 PWM Reverse at PWM speed

6

We cannot spot any evident issues with your setup. We suggest simply double-checking the setup and sample code based on the manufacturer’s site just in case (copying the setup and code):
dfrobot.com/wiki/index.php/ … U:_DRI0041
If you cannot spot any differences and the motors still do not work correctly, we’ll need to escalate to the manufacturer and can provide you with their contact information.

7

Thank you for your suggestion. I have changed ENA/ENB pins to PWM pins of Arduino board and then set PWM speed to 255. My circuit is working fine and there is no voltage drop. But, I didn’t understand what was the issue if ENA/ENB pins are connected to digital pins of arduino. There was voltage drop of 4V. Could you please help me to understand what is the difference?

8

It could be as simple as the sample code needs to correspond with the pins used.