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Author Topic: 2 Amperes Stepper Motor with 7239D help  (Read 1162 times)
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Hi,

Bear with me for such a noob help, I have a bipolar stepper motor having 2.63 V and 2.5 A. I am planning to use is with a 7239D h-bridge. I was trying to voltage divide it from a 4.5vin with two 100k ohms resistor. But the motor does not run. I know I am missing something here, could someone give me some advice? thanks
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Can't find such a thing as a 7239D h-bridge. Are you sure that's the correct number? You should also post a schematic of your circuit and the code you're using so we'll have sufficient information to diagnose your problem.
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Can't find such a thing as a 7239D h-bridge. Are you sure that's the correct number? You should also post a schematic of your circuit and the code you're using so we'll have sufficient information to diagnose your problem.

Maybe the OP means an L293D (maybe the OP is dyslexic?)...

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Ooopss my bad, I apologize it's L293D. After viewing it's datasheet it look like it cannot provide 2Amps to the motor to make it run, the h-bridge can only provide 1.2mA and that's not enough to make the motor happy. Any suggestion what component I can marry to this h-bridge to provide such Amps? thanks in advance.
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You mean 1.2A, not 1.2mA (!!)  - that's a peak value too, 0.6A is its continuous rating, so no it won't drive that motor (well barely!).  There are lots of chips that package up the 2 H-bridges needed to drive a bipolar stepper - with current limiting and various useful stuff, but 2.5A is quite high for these one-chip drivers - I did find the L6208 from ST which is available in both DIP and surface mount and handles 2.8A - needs heatsinking at those levels though.
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Thanks MarkIT yeah it won't be possible to run that motor, i'll take a look at the one you've mention maybe that'll solve my issues or else I'll just grab a different motor less headache hehehe. Thanks allot!
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Bear in mind that the motor should be matched in power to the load it needs to drive - and that should dictate the driver requirements.  If you need the power and torque you'll need a beefier driver circuit, if you can use less power/torque a smaller motor is a good idea (steppers take a lot of power at standstill...)

I think Pololu are currently out of stock of their nifty little stepper driver - I think its about up to the task (2A per winding) for yours - check it out, its a tiny yet powerful board using the A4983.
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Hi MarkT thanks for the advices, I tried a different motor this one is  bipolar from vexta model PK245-01AA which has a rating of 1.2A/phase 4v and with a resistance of 3.3 ohms. I based the design from a four wire circuit found here http://www.arduino.cc/en/Reference/StepperBipolarCircuit  with some adjustments.
  • 1. I am using 7239D
  • 2. I added five 0.1uF ceramics on pins 4,5,12, 13 and 16
  • 3. I also added a 100uF 10v on pins 8 and 16
  • 4. I also powered the circuit and the motor using arduino's Vin
I was able to run the motor however, I noticed that the H-bridge was taking up heat so fast. I'm assuming that the motor driver cannot handle the load from the stepper motor. Is there any way to avoid such heating issue? like adding a 7297? please advise.

Thanks again.
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