Hello,
I have an odd project with a need to run two 1/2hp 12V brushed DC motors in a variety of tasks.
The first task is that I need to run the motors quickly in one direction and then back in the other direction again and again. I’m assuming that’s pretty simple in concept. I could do that with a standard rheostat 2 direction Switch. I figure it’s actually HARDER to do that in code, but I’ll figure it out. (pointers and recommendations on software would be GREAT).
Another task is that I need to get something up to speed and then accelerate and decelerate it at least 11 times a second. aka for 1/11th of a second we accelerate and for the next 1/11th of a second we decelerate.
My ignorance is HUGE here. If I have something moving at speed and simply apply voltage in the “reverse” direction will it decelerate along a similar power profile (seems easier), or would “regenerative braking” be necessary?
If regenerative braking is necessary how detailed can the braking get on the different Pololu Motor Controllers? I’ve seen some controllers which have on/off regenerative braking and some which have multiple “power levels” of regenerative braking.
I’m guessing I can do what I need with a “Pololu Qik Dual Serial Motor Controller”? Is there a reason I should choose another one?
If the answers up until now are that this sounds viable is there the possibility of doing faster acceleration/deceleration? In the end I’m going to want to accelerate/decelerate probably 50-100 times/second. (weird project)
Err… After I posted this I realized a voltage of 12 volts will necessitate a 30 amp plus controller which limits my choices to the high end robotic one, however the other questions still apply. Anyone know about breaking and switching?
Hello.
The control methods for doing what you describe are going to depend almost entirely on your specific system. Unfortunately, we do not have any motor controllers with the kind of power it seems like you require.
-Brandon
pololu.com/product/2396
This system can handle 24V @ 30A right?
That’s what I was talking about…
Scott
The RoboClaw 2x30A Motor Controller can handle a continuous current draw of 30A and 24V is within its operating voltage range. However, I suspect this will not be adequate for your motor. It sounds like your 30A figure is probably just some rated current draw of your motor, and not the stall current, which can be many times the rated current. Please note that when a motor switches directions while running at full speed, it can briefly draw upwards of twice the stall current. Since it sounds like this will likely happen very frequently in your application, the RoboClaw 2x30A would likely still be underpowered.
-Brandon
ok. Say I decide to go with the 60A version and throw out the fast switching.
Do you still believe that the reverse/stall power will exceed the rated 120A of burst current? A 24v 1/2 HP motor should use 15.63A. That should mean the Controller would be rated 8x the “running” amperage. Would you consider that enough for a project reversing direction once a second?
Scott
I do not know enough about your motors to give you good answers to your questions. If you have the flexibility to use a 24V supply, then you can probably get a version of that motor with half the current draw, which should in turn be easier to find a motor controller for. You should try to figure out what the stall current of your motor will be and use that to judge what motor controller is suitable.
-Brandon
