[Milsurplus] 400 cycle 3 phase and WW2

[B Smith]

The earliest aircraft that I can remember  with 
main bus 400 cycle AC power was the KC-135(707), 
First manufactured in 1955?
I used to spend many moments  after starting 
engines trying to get all three alternators on 
line with those flashing lights blinking at 
    -       you had to get the timing just right.
Now come to think of it, why only three (3) ? 
Wonder why not 4 alternators ?   - -  one for each 
engine.
We had a lot of 400 cycle noise in everything.

73

breck k4che
--------------------------------------------------
From: "Mike Hanz" <aaf-radio-1 at aafradio.org>
Sent: Wednesday, January 12, 2011 2:08 PM
To: "Ray Fantini" <RAFANTINI at salisbury.edu>
Cc: <milsurplus at mailman.qth.net>
Subject: Re: [Milsurplus] 400 cycle 3 phase and 
WW2

> My Navy Airborne Electrical Maintenance Notes 
> pub dated September 1945
> shows no polyphase generators or inverters in 
> the Navy inventory as of
> that date.  I know that I have a couple of 3kVA 
> 28vdc rotary inverters
> that are dated in the 1950s that are three 
> phase, so the shift must have
> occurred after the end of 1945.  The 800-1 
> rotary inverter and NE-1
> through -5 series of engine driven alternators 
> that are in the AEMN are
> all single phase output.  I don't have a similar 
> list of the USAAF
> engine driven generators, but the mainstay of 
> the countermeasures work
> was an MG-149 inverter that is single phase 
> output.  Individual systems
> like the APQ-13 had their own rotary inverters 
> that were rapidly
> increasing in size, but to my recollection they 
> were all single phase
> until after the war as well.  It certainly makes 
> sense to go to three
> phase as time went by and the aircraft loads 
> increased at a rapid rate.
>
>  - Mike
>
> On 1/12/2011 1:46 PM, Ray Fantini wrote:
>> Thought all the old WW2 stuff ran from 28 volts 
>> DC and the B-36 was the first aircraft to 
>> exclusively use 115 volt 400 cycles 3 phase AC 
>> distribution? Being that AC distribution 
>> reduced design weight by several thousand 
>> pounds on a large aircraft. Recall reading 
>> something along this line in "Magnesium 
>> Overcast" by Dennis Jenkins. Maybe there was 
>> some application of 400 cycle AC prior to the 
>> B-36 but don't know what it would be. Did the 
>> old GO and GP transmitter have engine driven 
>> generators or motor generators  to develop 
>> their voltages from the ships DC distribution?
>
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