[ARC5] Dynamotor Capacitor

[Kenneth G. Gordon]

On 25 Mar 2014 at 11:29, Mike Feher wrote:

> Agreeing with John does not make it right, unless you also need your ego
> stroked daily.

No. I don't. 

But I do try to base what I believe on facts. It is a fact that ARC made 
thoroughly "grounding" the dynamotor frame to the receiver chassis their 
successful final solution to the elimination of dynamotor hash.

> Sparks do create radiated emissions, and grounding the
> dynamotor case does indeed minimize the amount radiated. The capacitor
> minimizes the amount conducted. When the brushes break L*(dI/dT) is
> tremendous.

Well, yes, it CAN be...if there is enough inductance associated with the 
circuit. I doubt if there is enough inductance within the dynamotor windings 
ALONE to cause "tremendous" spiking.

I suggest that we all stop all this "discussion", take an operating dynamotor 
which is mounted on an operating receiver and which is connected directly to 
a battery, and look at its output with a good 'scope, both with and without the 
capacitors in the circuit.

This will tell us definitively what is occuring rather then engaging in all this 
stupid bickering. I have always viewed empirical evidence as definitive.

Remember that in a large aircraft, and even in some smaller ones, the 
"distance" from the battery or generator to the dynamotor can be quite long. 
The added inductance of those long leads coupled with the inductance in the 
large generator, not to mention all the other "inductances" in the total 
"circuit", would certainly add to the problem. For OUR uses, I really doubt 
that such things would be of any concern whatever.

ARC undoubtedly provided for "worst case" scenarios.

Ken W7EKB