[Milsurplus] 800 CPS inverters

[Peter Gottlieb]

When I was a teen I picked up a power distribution unit which was 120/208 volts 3 phase 1600 Hz. It was aircraft but I have no idea what kind. 


Peter

> On Nov 17, 2017, at 9:53 AM, Michael Hanz <aaf-radio-1 at aafradio.org> wrote:
> 
> The 800Hz frequency was probably arbitrary, but the Navy did find that the weight savings in transformer and generator iron by doubling the line frequency was a bit more than "negligible", as one might surmise.  The British even used 1,600 Hz in their GEE and countermeasures equipment, prompting the U.S. to follow suit on their countermeasures gear so that the Brits could use it in their aircraft.  Several of my WWII jammers and surveillance receivers list 115/80 volt inputs at up to 1,600Hz as an alternative power source.
> 
> The problem with initial Navy standardization on 800Hz became clear only after more than one load began to be hung on generators and inverters.  The ugly head of power factor correction turned out to be a greater headache than the Navy engineers had anticipated, and hanging multiple loads on a single generator, especially loads that changed from one moment to the next, created voltage regulation problems and even damage to generating equipment.  That's the reason for the multiple switched compensation capacitors on the GO-9 and GP-7, plus other available "fixed" compensating capacitors like the Kellogg Type A condenser box at the bottom of the page at http://aafradio.org/flightdeck/go9.htm
> 
> That effect was much reduced at 400Hz, and the constant readjustment of loads - and damage to alternators for not properly doing so - finally drove the Navy to tacitly admit what it likely dreaded admitting...that the Army (and commercial aviation in the bargain) was right.  Oh well, it seemed like a good idea at the time.
> 
>           73,
>  - Mike  KC4TOS
> 
>> On 11/17/2017 8:24 AM, elden meyer via Milsurplus wrote:
>> There is a brief but interesting section on inverters
>> in volume 17 of the MIT Radiation Lab Series.
>> 
>> As mentioned here recently the author states that
>> the Navy choice of 800 CPS was more or less arbitrary
>> and made prior to the standardization on 400 CPS.
>> 
>> The series is on-line at:
>> 
>> https://www.jlab.org/ir/MITSeries.html
> 
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20171117/0b51a042/attachment.html>