Xref: utzoo sci.space:15752 sci.space.shuttle:4097
Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!ucsd!helios.ee.lbl.gov!ux1.lbl.gov!mikec
From: mikec@ux1.lbl.gov (Mike Chin)
Newsgroups: sci.space,sci.space.shuttle
Subject: Re: space news from Oct 2 AW&ST
Message-ID: <4300@helios.ee.lbl.gov>
Date: 28 Nov 89 02:09:15 GMT
References: <1989Nov26.223357.27453@utzoo.uucp>
Sender: usenet@helios.ee.lbl.gov
Reply-To: mikec@ux1.lbl.gov (Mike Chin)
Organization: Lawrence Berkeley Laboratory, Berkeley
Lines: 15

In article <1989Nov26.223357.27453@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>but will need regular fuel shipments from Earth.  The 20kHz AC power
>system is abandoned [good!] in favor of DC.   [Curious -- why not use the
>standard aircraft 400Hz AC?  Because that would be an admission that the
>ridiculous 20kHz stuff was a mistake?]  The thermal control system is being
Why is 20 kHz bad? I vaguely remember an article in Powertecnics describing
this system, but I wasn't aware of any controversy.

I was involved in a Explorer sat project where all voltages were derived
from a 28V bus; designing the DC-DC converters was a major effort (luckily
not done by me).

Mike Chin
Lawrence Berkeley Labs
MJChin@lbl.gov