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From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: [FlyRotary] Re: Radio noise progress
Date: Fri, 24 Feb 2006 22:27:58 -0500
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Thanks Bob. I'll try it.
Buly

On Feb 24, 2006, at 8:20 PM, Bob White wrote:

> Hi Buly,
>
> You will get more effective filtering by putting a choke in series
> with the lead to the offending unit.  Put the capacitor on the end
> away from the noise generator.  I looked at RS and only found one
> choke of 100uH, but it didn't give a current rating (p/n 273-102)
> They also have a snap together toroid core that you could use to make
> a choke.  Wrap as much wire, of the appropriate gauge to carry the
> current, as you can (p/n 273-104).  They also had ferrite choke core
> (p/n 273-105) that you can just clip around the wire.   It will work
> best if the noise is high frequency.  You should be able to reduce the
> size of the capacitor when used in conjunction with the choke.
>
> Bob W.
>
>
> On Fri, 24 Feb 2006 19:40:00 -0500
> Bulent Aliev <atlasyts@bellsouth.net> wrote:
>
>> This morning on the way to the hangar I bought some more ceramic disk
>> capacitors 0.01mF as suggested. Tried them on the fan. No change. The
>> fan is Spal brushles I think? It has separate return line to the
>> engine case.
>> While waiting for Jim to come with the oscilloscope, I connected
>> (temporary) the large 20A Radio Shack noise filter to filter the
>> incomming power to the avionics bus. BIG improvement! I would say 80%
>> reduction in fan, fuel pumps etc. noise.
>> Jim arrived with the o.scope and we connected it to the fan. Wow! You
>> can see the noise. Started trying different disc capacitors I had and
>> they did not make any difference. Jim asked me to buy few different
>> ones at RShack and left to take care of business, but left me the
>> o.scope. After trying few capacitors, 475mF did the trick.
>> Now the high pressure FI pumps. They were making one hell of a noise
>> filling the whole screen on the scope.
>> The avionics filter was taking care of most of it, bit I can still
>> hear them. Went twice more to RShack for bigger and bigger
>> capacitors. Finally the 2000mF made difference on the screen, but not
>> enough. On the way home I stopped again in RShack and got the biggest
>> one they had 5000mF and hope in the morning to see a flat line on the
>> screen :).
>> Next is the alternator, but had no time to run the engine today.
>> Thanks to everybody for your suggestions.
>>
>> QUESTION FOR TRACY: At all times with everything else turned off
>> except master, I hear quiet noise in the headset that's like a clock
>> ticking. If I disconnect the antenna from the radio it stops. I was
>> wandering if there is something in the EC that maybe doing this?
>> Buly
>>
>>
>>
>>
>>
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>
>
> -- 
> http://www.bob-white.com
> N93BD - Rotary Powered BD-4 (first engine start 1/7/06)
> Custom Cables for your rotary installation -
> http://www.roblinphoto.com/shop/
>
> --
> Homepage:  http://www.flyrotary.com/
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