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Message-ID: <43F4B031.5060003@gmail.com>
Date: Thu, 16 Feb 2006 11:02:41 -0600
From: Barry Gardner <barrygardner@gmail.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Radio noise saga
References: <list-987458@logan.com>
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Bill and other knowledgable folks,

Is there any value in  running a braided shielding inside the conduit 
that will carry the power leads? I'm building a plane like Buly's and 
want to know if that's something I should just build into my electrical 
raceway. Thanks.

Barry Gardner
Wheaton, IL

Bill Dube wrote:

> The separated power leads radiate noise quite well. They are a giant 
> loop antenna that is transmitting any ripple on the current to the 
> battery. Alternator whine, motor whine, ingnition system input ripple 
> all will radiate from such a loop.
>
> This is a very common problem on homebuilt electric vehciles. With the 
> large battery pack, folks often fine it convienient to run the power 
> leads up one side of the car and back on the other. The hash from the 
> motor controller and/or the charger make it impossible to use anything 
> electronic inside the car if you wire it that way. Sometimes, the 
> motor controller throttle input will pick up the output hash from such 
> a loop and make the car undrivable.
>
> Always run power leads as a pair. Keep the "presented area" low to 
> reduce the transmitted noise.
>
> You have found the problem.
>
>
>>
>> Twisted pair only reduces noise in signals transmitted THROUGH the 
>> wire, and it only works if the receiver uses a differential signal. 
>> It doesn't help with power wires. The curious can drop by:
>>
>> http://www.duxcw.com/digest/Howto/network/cable/cable4.htm
>>
>> It's a fairly good, brief description of what goes on. You'll usually 
>> only find twisted pair in LAN cabling.
>>
>> Regards,
>> Chad
>>
>> -- 
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>>
>
> -- 
> Homepage:  http://www.flyrotary.com/
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>