At 09:30 AM 6/9/97 EDT, Jim Phillips wrote:

>Uhhhhhhh. . . what I'm doing is splitting the two hot legs and using the
>neutral (not ground).  There are three wires in the 220 outlet from the
>UPS.  Normally (line power) I get 220 between the two hots, and 110 between
>either hot and the neutral.  So I just split the two hots and got my 110
>to run the console.  However, since the ground is bonded to the neutral
>somewhere down the line (usually at the main box), it's the same result
>when you go from either hot to ground.  But, just to be safe, I ran a
>four-wire cable to my 110 outlet: the two 220 hots, the 220 neutral, and
>a ground (which goes directly to the rack frame).
>
I misunderstood your description.  What you are doing is definitely the
right way to go.  The Electrical Code makes a big deal about the ground and
the neutral being different.  If you have a GFCI in the circuit, the
difference is crucial.
>
>>You said that you had measured 220V from one live wire to ground.   I'll
>>bet you got zero volts to the other leg (because it's grounded).
>
>Nope.  When the UPS is running, I get 220 between the two hots, and 220
>between either hot and the neutral.

That's weird.  Can't see how you can really get that unless the UPS is
producing 3-phase with one leg grounded (which I don't believe)!  Maybe the
UPS output is floating, in which case you can get some strange misleading
measurements.

>My point is: Since HP provides the PowerTrust UPS to allow you to perform
>an orderly shutdown of the system in the event of a power loss, and since
>you can't perform an orderly shutdown without a system console, why
>doesn't the UPS provide at least one 110 outlet for the system console?

I'm guessing that HP intends the 220V version of the 918 for non-US
installations that use 220V, in which case the console would run off 220V
also.  Why don't you have a 110V version of the 918?

John D. Alleyn-Day
Alleyn-Day International
408-286-6421   408-286-6474 (Fax)
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