[Milsurplus] dynamotor relics

[Mike Hanz]

As written, the challenge seems unprovable.  No definition is offered 
for the words "improved", nor "non-regulated", nor "difficult to 
maintain."   :-)  
.
Ray, no one is saying that your approach is a bad thing, or that it 
isn't a valid use of your radios.  I believe we all thank you for your 
viewpoint and wish you well in pursuing it.  I'm fond of (tube) 
regulated power supplies myself, when I can't find the correct dynamotor 
for a set, but regulation needs to be better defined before casting 
aspersions on rotating machinery.  The definition of regulation can be 
approximated at a first order of magnitude to the internal impedance of 
the supply, assuming a perfect voltage source in series with that 
impedance.  Paraphrasing Richard's observation, the internal impedance 
of a dynamotor is demonstrably lower than a good choke input power 
supply of an equivalent wattage design, both to steady state loads and 
actually even better to short period step function changes in loads, as 
you would experience sending CW.  It obviously can't be better than a 
regulated supply that has gain in a feedback loop, but the sets don't 
seem to be bothered too much by it. 
.
As to dynamotor maintenance, my somewhat limited experience with the 
roughly 43 dynos out in the aafradio rig has been that you generally 
have a one time chore of cleaning it and relubing the bearings, and 
that's about it for most of us - a lot less time than building a power 
supply, IIRC.  How many folks put a thousand hours a year on any 
*individual military set* that we own?  That's the point where you take 
the end bells off and check brush wear and clean out the carbon dust, 
but most of the time that's the only thing that's necessary.  I'll defer 
to others on whether the whine is music to the ears...Richard and I both 
have an 800Hz 801-1 inverter that probably takes that line of nostalgia 
a bit over the top, but earphones do wonders...heh, heh...
.
So that just leaves considering the word "improved".  I don't know what 
that means, since you have already established what you perceive as 
"normal" use, which is apparently a regulated power supply.  Under those 
circumstances, I guess no one can prove your challenge...   You win! :-P

73 and happy new year,
Mike  KC4TOS

Richard Brunner wrote:
>> I challenge anyone to prove how my use of the radio can be improved by using original non regulated and often difficult to maintain
>> dynamotors...
>>     
> Dynamotors have excellent regulation, especially dynamic regulation, far
> better than most ac supplies.  The main reason for poor performance
> reported for old WWII equipment is use of inadequate ac supplies.
> And yes, they do give nostalgic ambiance to the shack.  It doesn't get
> better than that...