Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: reflexsa on August 28, 2008, 02:08:45 PM
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Hi all,
I am building a small robot that will navigate a maze. The motors I am using are http://www.linengineering.com/line/contents/stepmotors/416-07.aspx (http://www.linengineering.com/line/contents/stepmotors/416-07.aspx)
I am using the 416-07-05.
I have the L297 and L298 set up almost like the datasheet, but there is no current sensing and the chopper is not connected. Also I dont really have space for 8 diodes per motor so I dont have those either.
This all seems to work, the L298 gets a bit hot as expected, but the L297 is also getting warm, I find this a bit strange.
Does anyone know if the L297 should be getting warm?
Thanks
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if you are giving it the amount of current and voltage that its rated for then you don't need to worry.
It should prob be warm , does it burn your finger or is it just warm.
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The L297 becomes warm to the touch, but the L298 gets a bit hot, I am going too heatsink it today.
As for the motors, the way I see it is that they will draw only the amount of current they were designed to draw because of the resistance of the windings?
The draw a little over 700mA per motor.
Thanks for any help
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OK everything is fine, nothing to worry about
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I am thinking about playing around with the L298. Would it be possible for someone who is using one to post a picture. I just want to get a visual. I have looked it up and read a lot about it already. I would like to see how someone here set it up. Nothing technical just a picture.
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There's a schematic etc on my Motor Controller tutorial
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Yea I checked it out. I was just wondering if someone could post a picture of how they have it used. Nothing technical just a photograph.
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Here ya go...
(http://www.bennetwilliams.com/img/electronics/L298 Motor Drive.jpg)
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Oh BTW...
You can add the flyback suppression diodes now or wait until you blow up a couple of L298's first.
Here's the principle...
When you are applying voltage to a motor coil and then you cut off that voltage (which is what a motor drive does), the coil can literally generate thousands of volts. This is alot of voltage. You can either supress it to your power rails, which is what the diodes do, or you can use that energy to destroy your L298. You choose ;)
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The pinouts are a bit of a swine with a 0.1" board - but are long enough that you can bend them to fit without a problem
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Nice! Thanks for the picture. This helps me a lot.
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I dont really have space for 8 diodes per motor so I dont have those either.
Look around for Diode Array IC's . . . basically a chip with multiple diodes in it for compact goodness :P
My Axon uses two capacitor arrays, fitting 8 caps in only 2 ICs.
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Good advice. Just make sure the diodes are "fast recovery" diodes.