MD30C not driving motor in same speed in both directions

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MD30C not driving motor in same speed in both directions

Postby sport1901966 » Wed Dec 12, 2018 10:41 pm

Hi all,

I have set up a motor control installation whereby the MD30C board is powered from a 24V 5A PSU, and is driving a 24V motor. I am using the A and B inputs wired to switches to control direction, and using the offboard potentiometer input, I have made a crude parallel resistor circuit combined with a 2 position switch to give two speed settings.

The problem I am having is that in one direction on 'full speed' the motor spins quickly as desired, but in the other direction it runs much slower, despite the only change being closing the switch on the A input rather than the B and visa versa.

Does anyone have any ideas why this is happening? I have two MD30C boards installed in the same way and they do they same thing.

Thanks!
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Re: MD30C not driving motor in same speed in both directions

Postby sport1901966 » Thu Dec 13, 2018 12:05 am

On further investigation I can see that it is the A direction in both cases that is running slowly.

I also noticed that the B LED lights up very faintly when I close the A direction switch, but when I close the B direction switch there is no sign of any light on the A LED

I tried swapping the motor cables over, and it then goes faster in the other direction (i.e. the correct speed output stays with the B direction), so the motor is OK

I have also tried swapping to the on board potentiometer but the problem is still present when I do
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Re: MD30C not driving motor in same speed in both directions

Postby ober » Thu Dec 13, 2018 5:38 am

Mind sharing your hardware setup? Picture of actual hardware setup will help a lot. Of course if you have video, that will be perfect :)
Ober Choo
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Re: MD30C not driving motor in same speed in both directions

Postby sport1901966 » Thu Dec 13, 2018 5:17 pm

Of course, I've attached a schematic of the installation to this post and couple of pictures of the actual hardware. I've also added a schematic of the two speed switch potentiometer layouts. Thanks for your help

MotorSpeedControlSchematic.PNG


SpeedPotInputArrangements.PNG


MD30CWiring.jpg


InstalledWiring.jpg
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