[Milsurplus] Interesting dynamotor fact

[boeing377 at gmail.com]

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> 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> 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> 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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