[Milsurplus] Variable Hertz AC Supply--Used For What?

[Mike Hanz]

On 5/7/2010 3:04 PM, Don Merz wrote:
> What good is this thing? It's an AC supply--looks to be in the 4-5 amp range made by Pacific Electronic Enterprises as their model PD-250D AC Power Source. Voltage seems to be variable from 0-150VAC and frequency is variable from about 40hz to 500Hz. Metered. Solid construction. Solid State.
>
> Whyforisthis? I was thinking that maybe it could be used to power 400hz aircraft dynamotors. But surely their startup current would crush this thing?
>
> Any ideas? I just want to sell it but I am not sure who would be interested in it!
>    

All the 400Hz inverters I'm familiar with use 28vdc, Don,  Selsyns use 
400Hz power, but they are usually a pretty small load and don't 
represent a large startup current.  Much of the WWII 400Hz equipment I'm 
familiar with (except transmitters) present a load within that range.  
For example, here are three pieces of intercept gear:

400Hz Power requirements:
AN/APA-10 panadapter - 140 watts
AN/APA-11 pulse analyzer (oscilloscope) - 196 watts
AN/APR-4  surveillance receiver - 125 watts

Or, since the harmonic content may be less than that of the power line 
(at least it is with my Behlman lab inverters) you could sell it to the 
audiophiles to provide more stage presence and transparency in their 
hum.  :-)

Best 73,
Mike  KC4TOS