HPE 9000 and HPE e3000 Servers
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Hi,

I have replaced 3 power supplies in a K-360 in less than two months. I think I have found the problem but I can't understand it. I measured the voltage on the power distribution strip and I read 120 volts between the lower pin and either of the top pins but when I measure the voltage between the top pins I read 208 volts. I first thought that my volt meter was bad but another meter reads exactly the same. I then thought that the UPS must be bad but when I read the voltage at the input, I get the same thing. Next I measured a completely different circuit in another part of the building and the same thing happened.

Any clue about what could cause this? Bad building transformer maybe? Should I call the power company?

TIA,
Bob
5 REPLIES 5

Hi (again),

I forgot to mention that I repeated these measurements at my home and this time I measured 120 volts and 240 volts just as I expected so I am pretty sure that there are serious electrical problems in our building.

Thanks (again),
Bob
Acclaimed Contributor
Solution

Not to worry, Bob; this is perfectly normal. Your building has 3-phase Wye-connected power. You need to think of 3 rotating vectors separated by 120 degrees.

Try this math:
240V * sin 120
or
120V * 3^0.5 (square root of 3)

Both of these are equivalent although the former is probably easier to visualize.

If it ain't broke, I can fix that.
Acclaimed Contributor

If it ain't broke, I can fix that.

Hi,

Thanks Clay. I would have felt really dumb if I had called our power company. I'm sure that I would have given them a chuckle. Since my power is normal, any ideas on why my power supplies are failing.

BTW, you must be an engineer to know that much about power.

Thanks,
Bob
Acclaimed Contributor