What is it called when the 60hz line power becomes something else?

From: William Donzelli <william_at_ans.net>
Date: Tue Jun 2 09:11:48 1998

> It's generally 400 (plus or minus 50) hz for aircraft and associated
> equipment (missiles for instance). Our test equipment racks for Air Launched
> Cruise Missiles had a HP 1000 computer tied to an IEEE 488 interface and all
> of that ran from a motor-generator that took 3 phase 220 volt _at_ 60hz to
> power an electric motor that turned a generator similar to an aircraft's
> engine driven generator.

Quite a bit of military equipment actually is rated to 2400 Hz. The reason
for this is that some of the pre-1940 aircraft (namely U.S.Navy) used 800
Hz power. There were also probably a few applications that went a bit
further in line frequency, but I am not aware of them. Anyway, an amazing
amount of this pre-war "junk" stayed in service into the 1970s.

If anyone wants a BIG 400Hz convertor from an IBM 3090 installation, there
is one in a junkyard in Illinois. It looks to be in the 1500 pound
category.

> Locomotives [...] also use 400hz equipment.

Maybe the new ones, but the old ones used 25 Hz.

William Donzelli
william_at_ans.net
Received on Tue Jun 02 1998 - 09:11:48 BST