[Milsurplus] Interesting dynamotor fact

[Bob Camp]

Hi

The “pressurized container” approach lived on for a very long time after that ……

Bob

> On Oct 9, 2023, at 7:07 PM, boeing377 at gmail.com wrote:
> 
> ARC 21 and ARC 65 solved the problem by having a pressurized container for the radios. 
> 
> On Mon, Oct 9, 2023 at 2:13 PM Ken Kinderman <scr274 at gmail.com <mailto:scr274 at gmail.com>> wrote:
>> I wonder if any other WW2 equipment solved that problem like the ART-13 with the air pressure-sensitive switch that reduced the HV above a certain altitude. Ten thousand feet? (I think the manual may mention the altitude)
>> 
>> 73,
>> 
>> Ken
>> W2EWL
>> 
>>> On Oct 9, 2023, at 2:45 PM, Jim Whartenby via Milsurplus <milsurplus at mailman.qth.net <mailto:milsurplus at mailman.qth.net>> wrote:
>>> 
>>> 
>> 
>>> Charlie, your guess is confirmed, see:
>>> http://catalog.teledynereynolds.com/Asset/1431.html#:~:text=At%20sea%20level%2C%20about%2030%2C000,will%20arc%20across%20the%20electrodes.
>>> 
>>> Wonder if a capacitor across the brushes would reduce the spark?  Works for point ignition systems.
>>> Regards,
>>> Jim
>>> 
>>> Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy
>>> 
>>> 
>>> On Monday, October 9, 2023 at 12:41:48 PM CDT, CL in NC via Milsurplus <milsurplus at mailman.qth.net <mailto:milsurplus at mailman.qth.net>> wrote:
>>> 
>>> 
>>> The fellow based in Atlanta that refurbishes WW II aircraft electric turrets, known as "The Turret Guy", has to also rebuild the amplidynes that make the power to run them.  We were talking brushes and I asked him where he was buying his.  But, he said that the amplidynes and dynamotors that run at ground level, last almost indefinitely compared to those that actually ran at 20-30,000 feet in their heyday.  Guessing the lower air pressure at altitude promotes more arcing and burns them up quicker.  He mentioned he had one turret he uses for demos he put brushes in many years ago and they still look almost brand new, after countless shows and demonstrations.
>>> 
>>> Charlie, W4MEC in NC
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