[Milsurplus] 800-1 800 cycle rotary inverter

[Mike Hanz]

Richard Brunner wrote:

> I note in the TBW instruction book that the generator in the 
> engine-generator set is a saturated pole design, designed for minimum 
> reactance and good regulation with changing load.  The 800-1 is not, 
> and maybe the reactance is changing with load.  I am glad I enjoy 
> challenges... 


I think you've put your finger on the problem, Richard.  The changing 
frequency has an effect on the series reactance as well.  I'm a little 
surprised that your regulator replacement didn't take care of the 
problem, but perhaps there isn't enough gain?  I've never worried about 
it with the GO-9, frankly - the 800-1 I was using for a while was within 
spec so it wasn't an issue.  Interestingly enough, the GO-9 manual is 
less than forthcoming about the line versus filament voltage question, 
but the GO-3 instructions offer some additional rationale:

"The filament voltage should not be allowed to fluctuate more than 0.2 
volt between key up and key down position when keying the transmitter, 
as this would indicate that the equipment is being operated with poor 
voltage regulation.  Voltage compensators are provided for correcting 
this condition.  Use of the compensating capacitors may be thought of as 
a means of tuning the generator and the primaries of the power 
transformers to resonance in order to have no variation in power between 
load and no-load conditions." 

So, the reason for focusing on the filament voltage wasn't so much for 
the filaments as to check health of the primary power system.  Funny how 
the "reasons why" seemed to disappear from later manuals.  Guess they 
didn't think the ops needed to know why...ours is but to do or die... :-)

I put some more pages from the AEMN regarding reactance nulling on the 
website at http://aafradio.org/docs/800-1.htm.  There are some 
interesting tidbits in there, including a reference to the "old" GO-9 
needing internal caps because of the lack of *external* capacitors (sort 
of implying that the internal caps are no longer needed with an external 
cap in the line), and a reminder that the engine driven generators 
varied frequency between 800 and 1,600Hz(!), so your measurements of 
output frequency for the 800-1 isn't out of the ordinary at all.

There is another (foldout) page that details the rather complex 
procedure used for adjustment of carbon pile voltage regulators that 
I'll try to get up later today.  I'm still packing radios for an 
impending QTH relocation.

Best 73,
Mike