[Milsurplus] Re 25hz

[Bob Camp]

Hi

If you really want to see a fun situation in terms of 50 / 60 Hz  
systems check out the ex-USSR. They have systems running on both  
standards. They used move gear from one plant to another depending on  
the military's needs. I have seen a number of plants over there with  
all sorts of frequency conversion gear in them. Often you can see  
rotary machines in one area, big vibrators (?) in another, and solid  
state stuff on the next floor.

It's always been amazing to me that they did not standardize on one  
frequency or the other.

Bob


On Nov 25, 2007, at 12:20 PM, W7QHO at aol.com wrote:

>
> In a message dated 11/25/07 6:30:44 AM, lafrance at att.net writes:
>
>
>> Here's a very interesting article about rotary frequency changers,  
>> a few of which were still in
>> service as of the article's 2003 date:
>> http://services3.ieee.org/organizations/pes/public/2003/sep/peshistory.html
>>
>
>
> Interesting article indeed.
>
> At a government site in the UK where I worked in the 70's there was  
> a building full of 50 to 60Hz rotary power converters which had been  
> found necessary to run earlier US equipment installed there.  With  
> the later capability of almost all electronics to work off of 50 -  
> 60 Hz power the converters were taken out of service, at which time  
> it was discovered that these units had been providing a very  
> beneficial power smoothing function in addition to frequency  
> changing,  Local 50 Hz mains power turned out to be rather dirty.  
> i.e., prone to numerous transients, surges and short interruptions  
> which the inertia of the heavy rotating components of the old system  
> had been filtering out for the most part.
>
> Dennis D. W7QHO
> Glendale, CA
>
>
>
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