Subject:
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RE: 3V motors
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 6 Aug 1997 20:50:12 GMT
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Original-From:
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Boeren, David C <dboeren@uscomm.comSAYNOTOSPAM>
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Viewed:
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1582 times
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Yes, it is true that altering the duty cycle does not alter the voltage.
What it
does do it alter the amount of current to the motor. The problem with
these
motors is that they draw too much current, more than the HB can readily
provide them. By using an ON/OFF duty cycle, you limit the current flow
to
a more manageable level, hopefully one within the limitations of the HB
and
its motor driver chip. The ON/OFF switching is fast enough that you can
for all practical purposes consider it to be smooth, so a motor that
normally
would draw 2 amps if run at a 100% duty cycle would only draw 1 amp when
run at a 50% duty cycle.
I'm pretty sure all that is correct without oversimplifying anything
important.
If anyone has corrections or more to add, please continue...
> ----------
> From: Owen Wessling[SMTP:OWESSLIN@us.oracle.com]
> Sent: Wednesday, August 06, 1997 2:12 PM
> To: handyboard@media.mit.edu; handyboard@media.mit.edu
> Subject: Re: 3V motors
>
> <<Message: Re: 3V motors>>
>
> Also, something to keep in mind regarding the motor drivers is that
> "lowering the power" doesn't change the drive voltage. I assume
> (ok, here's a chink in the argument, if this is wrong, I hope Fred or
> someone will correct me) that the handyboard uses power control code
> similar to the 6.270 boards, in which case powering a motor at 50%
> simply means that you drive the motor _at full power_ for about a 50%
> duty cycle; _not_ that you drive the motor at half-voltage.
>
> In service,
> Owen
>
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> -=
>
> Owen Wessling |
> Developer - Companion Products | "He who dies
> Visual Development Tools | with the most toys
> 415.506.4841 | is, nonetheless, still dead."
> owesslin@us.oracle.com |
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> -=
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>
>
>
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