Subject:
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Re: Inductor
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 15 Jun 1999 16:43:15 GMT
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Original-From:
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Satish Chetty <SATISHMK@spamcakeEMAIL.CAS.AMERICAN.EDU>
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Viewed:
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1639 times
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Tuesday, 15th day of June, 1999, 12:41 AM, EST.
Bart,
You are right, but I also heard that HB is designed to take care
of reverse emf WITHOUT a induction coil. The board is protected.
-Satish.
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On Tue, 15 Jun 1999 BART_SCHRIJVER@HP-Sonoma-om2.om.hp.com wrote:
> Denn:
>
> If I am not mistaken, and please correct me if I am wrong (anybody),
> but I think the inductor is in the circuit to protect the NiCd battery
> pack and rest of circuit against possible reverse electro-mechanical
> induction by the DC motors.
>
> Motor power is on the unregulated side of the power circuit.
>
> A DC motor is to convert DC power into mechanical energy, but it can
> also do the reverse, in this case the polarity would be opposite and
> be harmful to the battery pack.
>
> An inductor has an impedance that rises with frequency, so at
> f=infinity Z=high and at f=0 (DC) Z=0.
>
> So if the motor generate electricity the coil will short them out to
> ground and makes them stop as soon as power is removed by the L293D.
> IC has PWM routines in it to regulate power to the motor, so there
> will be a lot of on/off transitions, which can (and will) cause
> electro-mechanical induction.
>
> If you plan to use motors on your handyboard, you should use a coil to
> protect your circuit and battery against this phenomenon and the value
> is probably chosen based on the PWM frequencies and I would stay
> close to this value.
>
> Best regards, Bart Schrijver.
>
>
> ______________________________ Reply Separator _________________________________
> Subject: Inductor
> Author: Non-HP-denn (denn@technologist.com) at HP-PaloAlto,mimegw2
> Date: 6/14/99 9:54 PM
>
>
> Hi,
> I see the HB circuit and found the 1uH that connect the GND Batteries and
> GND.
> I want to know the purpose of this inductor. Can I replace it with other
> value or not use it .
>
> Thanks
>
>
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