[NSRCA-discussion] ESC and RX intereference

[Dean Pappas]

Hi Tom,
The BEC ground lead conducts all that common mode noise right to the receiver power supply. A BEC and high power will never co-exist well.
The shielding problem is the same as my answer to John: One of the shields has to go to Earth in order to fix the problem. We're back to flying CL again.
Dean

Dean Pappas
Sr. Design Engineer
Kodeos Communications
111 Corporate Blvd.
South Plainfield, N.J. 07080
(908) 222-7817 phone
(908) 222-2392 fax
d.pappas at kodeos.com


-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Tom Simes
Sent: Thursday, August 10, 2006 12:31 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] ESC and RX intereference


On Thu, 10 Aug 2006 11:42:59 -0400
"Dean Pappas" <d.pappas at kodeos.com> wrote:

> The problem, even though all these ESCs are
> opto-isolated, is that the ESC/servo lead is still an antenna that
> runs deep into enemy territory, picking up motor and ESC induced crud
> and putting it into the RX ground. That corrupts the receiver's
> measurement of the received signal.

Thanks for the explanation Dean, that really makes sense.

> Of course, distance is
> king. The optical link would then allow you to keep any radio wiring
> far from the power system.

I'm not sure I follow here.  I can understand the benefits of opto
isolating the RX throttle signal, keeping the RF radiating/receiving
wires short, and keeping the RX itself farther away from RF sources, but
if you are powering the RX with the ESC aren't you still susceptible to
the RX ground noise?

***Disclaimer - I know just enough about electronics to be dangerous and
my largest electric setups are 2C 450mAh & CC phoenix 10s so this
problem isn't affecting me.

What about using two pieces of ignition shielding - one to contain the
motor wires and a separate one to contain the BEC/servo lead from the
ESC?  

Something like this ignition shielding braid or the tinned copper braid
below it:

http://www.aircraftspruce.com/pdf/2007Individual/Cat07432.pdf

Tom
 
======================================================================
   "Z-80 system stack overflow.  Shut 'er down Scotty, the system's
         sucking mud" - Error message on TRS 80 Model-16B

Tom Simes                                       simestd at netexpress.com 
======================================================================
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