On Mon, 22 Jun 2020 15:34:37 +0000, Pommier, Rex wrote: > >I have a light - probably trivia by now - question for those of you who have >been around a while. My earliest experience with IBM disk was 3380s. They >ran 3 phase power, and if the phases weren't cabled correctly, the machine >wouldn't power up. I seem to recall hearing stories of (older than 3380) disk >drives that would start up, but the drives would spin backwards if the power >phasing was cabled incorrectly. Is there any truth to this story or was >somebody feeding me a line? > Not quite definitive, but: https://en.wikipedia.org/wiki/Three-phase#Revolving_magnetic_field https://en.wikipedia.org/wiki/Three-phase_electric_power#Phase_sequence
I knew a man who had worked in hardware field support for CDC. He told of his site's encountering such a problem. He summoned the union electrician required by shop contract. Electrician measured voltage pairwise between phases: "208v-208v-208v -- no problem!" My friend sneaked in after dark and rewired the motor-generator. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
