Re: PDP11/0x in my apartment? - VMS

This is a discussion on Re: PDP11/0x in my apartment? - VMS ; On Fri, 5 Mar 2004, Bob Hoffman wrote: > On Fri, 5 Mar 2004, Christopher Zach wrote: > > > RP's typically didn't have it, but the RP series were typically > > hard-wired into power and ran on their ...

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Thread: Re: PDP11/0x in my apartment?

  1. Re: PDP11/0x in my apartment?

    On Fri, 5 Mar 2004, Bob Hoffman wrote:

    > On Fri, 5 Mar 2004, Christopher Zach wrote:
    >
    > > RP's typically didn't have it, but the RP series were typically
    > > hard-wired into power and ran on their own breakers. RS03/04 drives also
    > > had the sequencers (and I believe they were MASSBUSS).

    >
    > RP0x drives in the USA had their power daisy-chained from one drive to the
    > next in groups of three. That is, the first drive plugged into a 30
    > amp, 3-phase outlet (NEMA L21-30), the second drive plugged into the
    > first and the third drive plugged into the second. If there was a 4th
    > drive, it was plugged into a separate 3-phase circuit.
    >
    > As the power passed through each drive in the chain, the phases were
    > rotated so that each drive's motor ran off a different phase in order to
    > balance the load.


    Huh? The RP drives use two phase motors, so while you didn't pull 3 times
    what one drive used doing that, you did double it.
    The dirves are connected to 3-ph power, but the motors use just 2-ph.

    Johnny

    Johnny Billquist || "I'm on a bus
    || on a psychedelic trip
    email: bqt@update.uu.se || Reading murder books
    pdp is alive! || tryin' to stay hip" - B. Idol
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  2. Re: PDP11/0x in my apartment?

    In article ,
    Johnny Billquist wrote:
    >On Fri, 5 Mar 2004, Bob Hoffman wrote:
    >
    >> As the power passed through each drive in the chain, the phases were
    >> rotated so that each drive's motor ran off a different phase in order to
    >> balance the load.

    >
    >Huh? The RP drives use two phase motors, so while you didn't pull 3 times
    >what one drive used doing that, you did double it.
    >The dirves are connected to 3-ph power, but the motors use just 2-ph.
    >


    Right--I think that's the idea. The first drive would use, say, phases
    1 and 2, the second would use 2 and 3, and the third would use 3 and 1.
    Thus each phase would be used by two motors. Pretty slick and effortless.

    --
    David Evans dfevans@bbcr.uwaterloo.ca
    Ph.D. Candidate, Computer/Synth Junkie http://bbcr.uwaterloo.ca/~dfevans/
    University of Waterloo "Default is the value selected by the composer
    Ontario, Canada overridden by your command." - Roland TR-707 Manual

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