[R-390] High Electrical hash noise level

[Curt Nixon]

What the heck kind of motor for a blower does that?

I haven't seen alot, but the ones I have seen are small 1/30HP reactance 
limited, induction motors that run at 3000 RPM direct drive to the draft 
inducing blower..usually a centrifugal or squirrel cage type.

Has trane gone techno and put in a brushless motor that requires a 
switching PWM drive or similar?  Surely no brushes.  But if it is a 
drive type PWM or vectored-flux motor, it could be the drive making the 
noise, not the motor.

Unless the motor just has some resonant condition where the windings 
radiate at the switch freq or harmonic.

Very curious.

Curt


Steve Toth wrote:
> Al
> I believe you are correct and this could be defined as a factory defect for the furnace.  Contacting the ARRL is a good idea - I hadn't thought of that.
>  
> I was able to find quite a few threads on the internet by searching on "radio interference Trane furnace", so you're probably correct about the strength of the claim also.
>
> I just think it's kind of crazy to have one of the most sensitive receivers ever designed, if not the most sensitive, and have it knocked completely deaf by a "eco-friendly" design flaw in a furnace.
>
>
>
>
>
>
>
> -- Steve, K7PZN 
> "Think Quickly, Speak Slowly, Work Diligently, Live Simply"
>
> --- On Mon, 3/28/11, Al Parker <anchor at ec.rr.com> wrote:
>
>
> From: Al Parker <anchor at ec.rr.com>
> Subject: Re: [R-390] High Electrical hash noise level
> To: "Steve Toth" <stoth47 at yahoo.com>, r-390 at mailman.qth.net
> Date: Monday, March 28, 2011, 2:02 PM
>
>
> Hi Steve, et al,
>     I sympathize with your dilemma.  But, isn't it so that the manufacturer of a device must comply with FCC rules regarding interference, particularly to a licensed service such as amateur radio?  A similar, but more widespread, problem has occurred with BPL.
>     If you don't get relief from the dealer/mfgr, alert the ARRL, their tech. group might have some ideas, and their legal group has been involved in this sort of thing.  You should not have to buy any special filters, etc., to be able to use your equipment.  If there is widespread evidence showing a known and ongoing problem, I think you've got some strong grounds to stand on.
> 73,
>
> Al, W8UT
> www.boatanchors.org
> www.hammarlund.info
>
> "There is nothing -- absolutely nothing -- half so much
> worth doing as simply messing about in boats"
> Ratty, to Mole
>
> On 3/28/2011 4:26 PM, Steve Toth wrote:
>   
>> Bob et al,
>> Here's the latest:  I did some digging on the internet.  Turns out this problem has been around since 2006 with Trane and American Standard Hi-Efficiency furnaces.  The source is the fan inducer motor - they went to a new design of the motor they used.  It generates strong RFI (S9 levels) from the broadcast band all the way up through VHF and UHF - wipes out AM radios, TVs, routers, etc.
>>
>> Trane is apparently aware of the problem.  They have a shielded cabling kit that can replace the inducer motor wiring harness which acts like an antenna.
>>
>> I called the servicing dealer and the "technical expert" phone rep I talked to was clueless.  After I told her the exact problem, the source of the problem and the factory fix for the problem (with part numbers) - with her taking notes - she put me on hold.  She came back online after talking to someone to tell me "yes, there was a wiring kit that they could install but it may or may not eliminate the problem."
>>
>>     
>>> From what I researched, it appears that the shielded harness sometimes solves the problem and sometimes does not.  But from what I could tell from the posts I read, it looks like it really depends on what kind of RF ground is installed on the shielded harness and furnace and how complete the shielding is on the inducer harness that determines how effective the fix is.  If the installation of the shielded harness works the noise level has been reported to drop to minimal levels.  Right now the furnace has an electrical ground but no RF ground, so it appears I'm going to have to install one.
>>>       
>> The dealer service manager is supposed to call me back and let me know what they can do for me.
>>
>>
>> -- Steve, K7PZN
>> "Think Quickly, Speak Slowly, Work Diligently, Live Simply"
>>
>>     
>
>
>
>       
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