400 HZ

[dreman]

Why do the military uses 400hz in weapon systems?

 

[waross]

I've lost several of my most interesting friends to the boys in the black choppers.
Gee, I hope Scotty's OK. I wonder where???
Kidding aside, I worked at a dive resort where the senior staff would reminisce about the time the black choppers landed on the beach and the resort manager was removed by the boys in black.
(He was later released in another country with no money and incomplete documents and left to make his own way back home.)
I eventually met the man and got the story first hand.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[edison123]

All this frenzy over frequency ?

 

[EmergencyPowered]

Up until IBM left the 3090 class of mainframes, all IBM mainframes required massive 208v/400hz power converters. It made a much better DC rail due to easier filtering.

 

[itsmoked]

I went in a room once at the company that made knock off IBM mainframes, don't recall the name but it was in San Jose. There were two hundred rotary phase converters running there. It was kinda different.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[DanEE]

To my knowledge the IBM 370/145 was the first mainframe to use 400hz power.. It had a large motor/generator in a very well accousticly engineered enclosure right on the raised floor next to the main processor that did the dirty deed.

The sound was unmistakeable on the raised floor, akin to the 400hz whine you hear in the heavies (aircraft) kind of cool

Also kind of cool doing a cold power start on one of these puppies.. A stepper switch in the main processor unit bought up one peripherial system unit at a time to spread out the power load ramp up. Each unit was remote started via control lines in the EPO cable (power start/power good handshake that advanced the stepper switch).

 

[Zogzog]

I hated changin the brushes on the 400HZ MG sets, or any maintenence on them for that matter, too small to work on (in)

 

[itsmoked]

Interesting stuff.

Amdahl Computers! I couldn't stand it any longer I had to look it up.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[controlsdude]

When I was in the navy we had solid state 400 hz converters, No 400hz MG sets. The only time it tripped was when our transmitter took a dump and tripped it off line. Never went down for long periods of time. I wonder why people still use MG sets, must be the price.

 

[ozmosis]

400Hz is used extensively in the woodwork industry too for operating the high-speed routing spindles. In the past they had rotary converters but nowadays it is genrally VFD technology to get the spindles up to speed. They would typically be spinning at about 24,000rpm so could be used as a weapon in the wrong hands..

 

[EEJaime]

Gentlemen,

It is not only military weapons and aircraft that use 400Hz power systems. Commercial aircraft use them as well. At each Passenger boarding bridge we have a connection from either a centralized 400Hz distribution systems or in the case of newer installations, a point of use MG set mounted right to the bridge to power the aircraft when the engines are not running.

We had a few fail last year and the airports we are involved with seem to be moving toward the point-of-use systems.

Just FYI