nuckolls.bob(at)cox.net Guest
|
Posted: Wed Jun 04, 2008 11:10 am Post subject: SD-8 noise issues |
|
|
At 09:47 AM 6/4/2008 -0400, you wrote:
Quote: |
<aerobubba(at)earthlink.net>
glen matejcek
aerobubba(at)earthlink.net
>
> Time: 10:49:57 AM PST US
> From: "Larry L. Tompkins, P.E." <tompkinsl(at)integra.net>
> Subject: Re: SD-8 vs. SD-20 choice
>
> Ernest:
>
> It is my understanding that the SD-20 has both a wound stator and a
> wound coil, i.e., no permanent magnets. Therefore it is "off" until
> power to the field windings is switched on.
>
> Let me try to do a better job asking my question. The SD-8 is
> continuously producing output.
That is a misleading statement. Under normal ops, the SD-8 is creating a
voltage, but no current. Much like a battery sitting on a shelf.
|
<snip>
Quote: | The one thing that I could foresee being a problem would be if one ran a
system wire, especially a sensor wire from a thermocouple, right next to
the SD-8 installation. The spinning magnetic field of the SD-8 could
impose a signal over the weak signal from an EGT (or other) sensor. The
twisted pair of wires on these sensors should help mitigate that situation.
Also, I don't recall ever hearing anyone mention such an issue in this
forum, so I suspect it's a pretty low order threat.
FWIW, and I hope this helps-
|
Nice response Glen. There IS a significant magnetic
field outside the SD-8 housing. Of course, spinning
that housing offers a potential for generating magnetically
coupled noises into any adjacent conductors. However,
given that all sensors to the engine SHOULD be carried
on twisted inbound/outbound conductors, the effects of
this noise should be zero.
Bob . . .
| - The Matronics AeroElectric-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|