Choice of DC motor - shield v2

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mafieulemouton
 
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Choice of DC motor - shield v2

Post by mafieulemouton »

Good morning,
I bought your motor shield V2 to discover motor control with arduino and I'm glad this is working nicely.
However, the only DC motor you propose on your website is really not powerfull, and I'm desperately trying to find the most powerfull motor with this shield.
I had on look on the internet, but all I can find are very small motors like yours or too powerfull motors with 15A peak.

Would you recommend me a nice DC motor matching the 1A limitation of your shield? (That would be nice to add it in your shop as well!)

Tanks for your help.

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adafruit_support_bill
 
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Re: Choice of DC motor - shield v2

Post by adafruit_support_bill »

That depends on what you mean by "powerful". What are you trying to do with it? https://learn.adafruit.com/adafruit-mot ... tion-guide

I suspect you are looking for something with more torque. In that case, a gear motor would be a good choice: https://learn.adafruit.com/adafruit-mot ... red-motors

I have a gear motor designed for opening skylights that works with the shield. It has awesome torque, but is extremely slow. There are plenty of other gear motors with various gear ratios that work well with it also. Pololu has an excellent selection of gearmotors in various sizes. http://www.pololu.com/category/51/polol ... gearmotors

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mafieulemouton
 
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Re: Choice of DC motor - shield v2

Post by mafieulemouton »

Thanks for your answer, and sorry not to be precise enough. (Please excuse also my English that may not be beautiful)

I want to use this motor as secondary propulsion for a 1m boat model. (The main propulsion being sail)

I don't know anything about this, but I was thinking it would be better having a motor with at the same time more torque and keep a good speed.

The geared motor you linked seems nice, but may be a little too slow. I really need to investigate more, but I can't find the information on the internet whether I need more rotation speed or more torque..

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adafruit_support_bill
 
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Re: Choice of DC motor - shield v2

Post by adafruit_support_bill »

For a boat of that size, you probably need both speed and torque. Most of the model boat motors I have seen are brushless DC motors: https://learn.adafruit.com/adafruit-mot ... -dc-motors
For these, you need a brushless motor controller.
https://learn.adafruit.com/adafruit-mot ... or-control
Typically, that would be an "ESC" (Electronic Speed Control) that is controlled by a standard RC servo signal. It is easy to generate the servo signal from an Arduino. You can use one of the servo headers on the motor shield.

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mafieulemouton
 
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Re: Choice of DC motor - shield v2

Post by mafieulemouton »

Ok, I understand. I found this kit at amazon.com : http://www.amazon.fr/Model-Outrunner-Br ... 00E56H63Y/

Would it fit for me? Can I drive it with your servo shield? And if yes, can I use the same AA alim for the shield and the brushless motor?

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Re: Choice of DC motor - shield v2

Post by adafruit_support_bill »

You should be able to control the ESC with the servo shield. But the motor requires 10A of power. You will need something much more powerful than AA cells.

I'm not sure if that motor size or configuration is appropriate for your boat. We are not experts in that area. I recommend that you check with a forum that specializes in boats. Once you select a motor, we can help you with the power and control.

http://www.rcgroups.com/boats-54/

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mafieulemouton
 
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Re: Choice of DC motor - shield v2

Post by mafieulemouton »

Ok thanks for your help, I'll invastigate and come back to the thread later.

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mafieulemouton
 
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Re: Choice of DC motor - shield v2

Post by mafieulemouton »

Hi again,
I checked at the RCgroups forum, they said my small dc moteur would just do the job with no wind but it would be so slow.
So I'm gonna buy a brushless dc motor as you suggested. Would you think this motor kit would fit with this battery?

And have you got a tutorial to drive this with the adafruit servo-shield? Thanks for your help

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Re: Choice of DC motor - shield v2

Post by adafruit_support_bill »

That motor is rated for 10A continuous. The battery capacity is 2800mAh or 2.8Ah At 10A, your run-time with that battery is 2.8/10 or 0.28 hours. That works out to about 16.8 minutes.

We do not have a tutorial for running brushless DC motors. But it is not too complicated. We should be able to answer any questions you have here in the forums.

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Re: Choice of DC motor - shield v2

Post by mafieulemouton »

Ok, but lets say I use only half of the motor power with PWM, I will get twice batery duration?

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Re: Choice of DC motor - shield v2

Post by adafruit_support_bill »

In general, yes. You will need to take some measurements to determine what the actual current draw is at various PWM levels to determine the expected run-time for your boat.

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Re: Choice of DC motor - shield v2

Post by mafieulemouton »

Ok thanks a lot. I'm ordering and trying this, and if any problem I will create a topic in the servo shield forum.

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