In a message dated 1/19/2006 7:46:52 A.M. US Mountain Standard Time, [EMAIL PROTECTED] writes:
I just won a GSA auction for a 400 Hz/60 Hz 25kVA motor >generator set. I'm not sure whether it eats 400 Hz or >60 Hz. Regardless, in a perfect world I can hook a diesel >to the end shaft and spin it. In a really perfect world, >both the 400 Hz and 60 Hz machines are synchronous, and >both can be generators. 400 Hz will drive resistive loads >(like my furnace elements) just fine. Jim, Nearly all applications take 60Hz power and turn the 400Hz generator, the output of which is very easy to convert to a ripple free DC power. You are correct that 400Hz will run resistive loads quite well. Power cables carrying 400Hz had to be oversized as the current flows primarily on the surface of the conductors. Mg sets also used inertia to carry them through small power transients, such as switching from shore power to onboard power. Ride through was typically 30cycles, or about 1/2 a second. Typical applications would be big computers, radar, and communications gear, all of which don't like being turned off. All have big DC power supplies. I recall IBM and Hitachi mainframes having as many as 5 MG sets built into them during the 90's, Your 2000 # plus MG sounds a bit heavy for an aircraft, but that is out of my field of endeavor. Now, main frames fit in a desk space, run off two 30amp, 60 Hz, services, and MG sets ( and old mainframes for that matter) can be had for the cost of toting them away. I recall one buyer, who paid $1 for each mainframe, shipped them to China to have them stripped for all the various metals. Thanks for the memories, Jim Friesen Phoenix AZ 79 300SD, 262 K miles 98 ML 320, 140 K miles
