MicroVAX model 3100 on 208V 3-phase power - VMS

This is a discussion on MicroVAX model 3100 on 208V 3-phase power - VMS ; Just in case anyone's interested, it works! My MicroVAX fleet has been running fine since 14-JUL-2008. No power supplies have been fried so far. AEF...

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Thread: MicroVAX model 3100 on 208V 3-phase power

  1. MicroVAX model 3100 on 208V 3-phase power


    Just in case anyone's interested, it works! My MicroVAX fleet has been
    running fine since 14-JUL-2008. No power supplies have been fried so
    far.

    AEF

  2. Re: MicroVAX model 3100 on 208V 3-phase power


    "AEF" schreef in bericht
    news:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com...
    >
    > Just in case anyone's interested, it works! My MicroVAX fleet has been
    > running fine since 14-JUL-2008. No power supplies have been fried so
    > far.
    >
    > AEF


    Umm, mine run on 230 V single phase...
    I'm not familiar with US mains power supplies. In the Netherlands we have
    single and 3-phase.
    3-phase is: three live wires, one neutral and one ground. Five wires in
    total. Single phase is either just two wires, live and neutral or three:
    live, neutral and ground.
    There is no potential difference between the three live wires, though
    (since it's AC) they are out of phase.
    So, using a 3-phase connector (in the Netherlands), I can select one live
    wire, plus neutral and ground and run any domestic device on it without a
    problem, be it a VAX, an Alpha or a toaster.
    Unless US models have a different wiring scheme I fail to see how you can
    connect three live wires to a 3100?
    Hans



  3. Re: MicroVAX model 3100 on 208V 3-phase power

    On Oct 2, 6:50 pm, "H Vlems" wrote:
    > "AEF" schreef in berichtnews:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com...
    >
    >
    >
    > > Just in case anyone's interested, it works! My MicroVAX fleet has been
    > > running fine since 14-JUL-2008. No power supplies have been fried so
    > > far.

    >
    > > AEF

    >
    > Umm, mine run on 230 V single phase...
    > I'm not familiar with US mains power supplies. In the Netherlands we have
    > single and 3-phase.
    > 3-phase is: three live wires, one neutral and one ground. Five wires in
    > total. Single phase is either just two wires, live and neutral or three:
    > live, neutral and ground.
    > There is no potential difference between the three live wires, though
    > (since it's AC) they are out of phase.
    > So, using a 3-phase connector (in the Netherlands), I can select one live
    > wire, plus neutral and ground and run any domestic device on it without a
    > problem, be it a VAX, an Alpha or a toaster.
    > Unless US models have a different wiring scheme I fail to see how you can
    > connect three live wires to a 3100?
    > Hans


    Well, 208 is 120*3**0.5 and 120V is the normal nominal voltage in
    American households and offices.

    They tell me it's 208V 3-phase. I have a power cord that has three
    prongs surrounded by a sleeve. I plug that into the power strip
    mounted just inside the door frame of the cabinet and it works!

    It looks like your 3-phase and my 3-phase are two different creatures.

    AEF

  4. Re: MicroVAX model 3100 on 208V 3-phase power

    On 3 okt, 02:29, AEF wrote:
    > On Oct 2, 6:50 pm, "H Vlems" wrote:
    >
    >
    >
    >
    >
    > > "AEF" schreef in berichtnews:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com...

    >
    > > > Just in case anyone's interested, it works! My MicroVAX fleet has been
    > > > running fine since 14-JUL-2008. No power supplies have been fried so
    > > > far.

    >
    > > > AEF

    >
    > > Umm, mine run on 230 V single phase...
    > > I'm not familiar with US mains power supplies. In the Netherlands we have
    > > single and 3-phase.
    > > 3-phase is: three live wires, one neutral and one ground. Five wires in
    > > total. Single phase is either just two wires, live and neutral or three:
    > > live, neutral and ground.
    > > There is no potential *difference between the three live wires, though
    > > (since it's AC) they are out of phase.
    > > So, using a 3-phase connector (in the Netherlands), I can select one live
    > > wire, plus neutral and ground and run any domestic device on it withouta
    > > problem, be it a VAX, an Alpha or a toaster.
    > > Unless US models have a different wiring scheme I fail to see how you can
    > > connect three live wires to a 3100?
    > > Hans

    >
    > Well, 208 is 120*3**0.5 and 120V is the normal nominal voltage in
    > American households and offices.
    >
    > They tell me it's 208V 3-phase. I have a power cord that has three
    > prongs surrounded by a sleeve. I plug that into the power strip
    > mounted just inside the door frame of the cabinet and it works!
    >
    > It looks like your 3-phase and my 3-phase are two different creatures.
    >
    > AEF- Tekst uit oorspronkelijk bericht niet weergeven -
    >
    > - Tekst uit oorspronkelijk bericht weergeven -


    Yes it does. We get 400V between live wires. Live-to-Neutral is always
    230 V.
    Did you have to change something inside the power supply of the VAX?
    Hans

  5. Re: MicroVAX model 3100 on 208V 3-phase power

    On 2008-10-03 02:29, "AEF" wrote:

    > Well, 208 is 120*3**0.5 and 120V is the normal nominal voltage in
    > American households and offices.
    >
    > They tell me it's 208V 3-phase. I have a power cord that has three
    > prongs surrounded by a sleeve. I plug that into the power strip
    > mounted just inside the door frame of the cabinet and it works!
    >
    > It looks like your 3-phase and my 3-phase are two different creatures.


    Not really -- you get 208 volts between *two* of the "live" wires
    (L1-L2, e.g.), i.e., you are running a "delta" three phase scheme, while
    Hans gets 230 volts between *one* of the "live" wires and the "neutral"
    wire (L1-N, e.g.), i.e., he is running a "Y" three phase scheme.

    Michael

    --
    Real names enhance the probability of getting real answers.
    My e-mail account at DECUS Munich is no longer valid.

  6. Re: MicroVAX model 3100 on 208V 3-phase power

    On Oct 3, 3:06*am, H Vlems wrote:
    > On 3 okt, 02:29, AEF wrote:
    >
    >
    >
    > > On Oct 2, 6:50 pm, "H Vlems" wrote:

    >
    > > > "AEF" schreef in berichtnews:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com...

    >
    > > > > Just in case anyone's interested, it works! My MicroVAX fleet has been
    > > > > running fine since 14-JUL-2008. No power supplies have been fried so
    > > > > far.

    >
    > > > > AEF

    >
    > > > Umm, mine run on 230 V single phase...
    > > > I'm not familiar with US mains power supplies. In the Netherlands we have
    > > > single and 3-phase.
    > > > 3-phase is: three live wires, one neutral and one ground. Five wires in
    > > > total. Single phase is either just two wires, live and neutral or three:
    > > > live, neutral and ground.
    > > > There is no potential *difference between the three live wires, though
    > > > (since it's AC) they are out of phase.
    > > > So, using a 3-phase connector (in the Netherlands), I can select one live
    > > > wire, plus neutral and ground and run any domestic device on it without a
    > > > problem, be it a VAX, an Alpha or a toaster.
    > > > Unless US models have a different wiring scheme I fail to see how youcan
    > > > connect three live wires to a 3100?
    > > > Hans

    >
    > > Well, 208 is 120*3**0.5 and 120V is the normal nominal voltage in
    > > American households and offices.

    >
    > > They tell me it's 208V 3-phase. I have a power cord that has three
    > > prongs surrounded by a sleeve. I plug that into the power strip
    > > mounted just inside the door frame of the cabinet and it works!

    >
    > > It looks like your 3-phase and my 3-phase are two different creatures.

    >
    > > AEF- Tekst uit oorspronkelijk bericht niet weergeven -

    >
    > > - Tekst uit oorspronkelijk bericht weergeven -

    >
    > Yes it does. We get 400V between live wires. Live-to-Neutral is always
    > 230 V.
    > Did you have to change something inside the power supply of the VAX?
    > Hans


    No. I was concerned because the voltage specs are the following:

    Input voltage Automatically adjusting ac input. Range: 100 V ac to 120
    V ac or
    220 V ac to 240 V ac.

    Notice the "or". But it works anyway! I thought it probably would, but
    was concerned as we have only a few 120V power strips and only every
    3rd cab or less.

    AEF

  7. Re: MicroVAX model 3100 on 208V 3-phase power

    "H Vlems" writes:


    >"AEF" schreef in bericht
    >news:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com...
    >>
    >> Just in case anyone's interested, it works! My MicroVAX fleet has been
    >> running fine since 14-JUL-2008. No power supplies have been fried so
    >> far.
    >>
    >> AEF


    >Umm, mine run on 230 V single phase...
    >I'm not familiar with US mains power supplies. In the Netherlands we have
    >single and 3-phase.


    We went through this in a long thread months ago. In the US power
    supplied to homes is 120/240 volts through a center tapped transformer.
    Most things are wired from one of two hots to a neutral (the center tap)
    and get 120V. Larger items are connected between both hots and get 240V.

    Businesses usually get 3 phase power. The voltage is 120/208V. (there is
    also 277/480V for large consumers) There are 3 hots, a neutral and ground.
    The voltage between any hot and the neutral is 120V, and the voltage
    between any two hots is 208V. The 120V hot to neutral is the same as home
    power so ordinary things like coffee pots or Microvaxes will still work.

  8. Re: MicroVAX model 3100 on 208V 3-phase power

    Michael Moroney wrote:
    > "H Vlems" writes:
    >
    >
    >> "AEF" schreef in bericht
    >> news:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com...
    >>> Just in case anyone's interested, it works! My MicroVAX fleet has been
    >>> running fine since 14-JUL-2008. No power supplies have been fried so
    >>> far.
    >>>
    >>> AEF

    >
    >> Umm, mine run on 230 V single phase...
    >> I'm not familiar with US mains power supplies. In the Netherlands we have
    >> single and 3-phase.

    >
    > We went through this in a long thread months ago. In the US power
    > supplied to homes is 120/240 volts through a center tapped transformer.
    > Most things are wired from one of two hots to a neutral (the center tap)
    > and get 120V. Larger items are connected between both hots and get 240V.
    >
    > Businesses usually get 3 phase power. The voltage is 120/208V. (there is
    > also 277/480V for large consumers) There are 3 hots, a neutral and ground.
    > The voltage between any hot and the neutral is 120V, and the voltage
    > between any two hots is 208V. The 120V hot to neutral is the same as home
    > power so ordinary things like coffee pots or Microvaxes will still work.


    The 277/480V service is not so much for "large consumers" as for
    customers operating equipment that requires those voltages. Those big
    Liebert air conditioners in your computer room may require 277/480V.
    Customers with this service generally also have 120V for lighting,
    coffee pots, desktop computers, etc.

  9. Re: MicroVAX model 3100 on 208V 3-phase power

    On 3 Oct, 16:55, "Richard B. Gilbert" wrote:
    > Michael Moroney wrote:
    > > "H Vlems" writes:

    >
    > >> "AEF" schreef in bericht
    > >>news:4e1c5938-3bfd-4823-97ac-dacf7249f0e3@y79g2000hsa.googlegroups.com....
    > >>> Just in case anyone's interested, it works! My MicroVAX fleet has been
    > >>> running fine since 14-JUL-2008. No power supplies have been fried so
    > >>> far.

    >
    > >>> AEF

    >
    > >> Umm, mine run on 230 V single phase...
    > >> I'm not familiar with US mains power supplies. In the Netherlands we have
    > >> single and 3-phase.

    >
    > > We went through this in a long thread months ago. *In the US power
    > > supplied to homes is 120/240 volts through a center tapped transformer.
    > > Most things are wired from one of two hots to a neutral (the center tap)
    > > and get 120V. *Larger items are connected between both hots and get 240V.

    >
    > > Businesses usually get 3 phase power. *The voltage is 120/208V. *(there is
    > > also 277/480V for large consumers) There are 3 hots, a neutral and ground.
    > > The voltage between any hot and the neutral is 120V, and the voltage
    > > between any two hots is 208V. *The 120V hot to neutral is the same ashome
    > > power so ordinary things like coffee pots or Microvaxes will still work..

    >
    > The 277/480V service is not so much for "large consumers" as for
    > customers operating equipment that requires those voltages. *Those big
    > Liebert air conditioners in your computer room may require 277/480V.
    > Customers with this service generally also have 120V for lighting,
    > coffee pots, desktop computers, etc.- Hide quoted text -
    >
    > - Show quoted text -


    A long ago copy of the IEE Wiring Regs in the UK stated that motors
    above 1HP (about 750W) shouldn't be powered off single phase and
    should be off three phase power instead. Your vacuum cleaner and hand
    drier come in at 500W at most usually so it's only for people that
    have big machine tools at home (metalworking lathes are a particular
    candidate here).

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