HP 9000 K570 E4456B PDU Problem

[Bernd Huber]

Hi all,
this might sounds embarrassing, however we are having a problem connecting a couple of our HP A1884 Cabinets to our power grid.
We got the cabinets back from our remote site where they were plugged into 220 V single phase.
Upon their return we wanted to plug them into our power grid, however we only have 208 V three phased.
It is a E4456B PDU to supply the power for a K570/460.
The question is can I just change the plugs of the PDU or is the phasing going to screw me up ?
Is there any way to get a hold of the schematics of the PDU ?
Is there a transformer internally to the PDU ?

Anybody a clue ?

Thanks in advance

Bernd Huber

[MANOJ SRIVASTAVA]

Hi Bernd

3 Phase vs single phase , it depends on the load on the other phases too , how it is done at the source layer is that there is a star tranformer which has 3 induction coils and all of them connected on one end which is the return path for the AC , genreally it is grounded to make the refernce a zero . Now if you are connecting the PDU to one coil ( one phase ) there should be similar loads on the other coils too , though a PDU will not cause much of the voltage drop. Donot also use a heavy current device lika a A/C on the same phase . I hope this answers some of the issues.


Manoj Srivastava

[harry d brown jr]

DO NOT CHANGE THE PLUG!!!!

GET the PROPER PDU!

live free or die
harry

[A. Clay Stephenson]

You will have no problem. Remember, in a 3-phase wye the power supplied between any two legs is single-phase. If you measure between any of the legs and neutral, you will see something like 120 VAC (rms). The question is why don't you see 240 VAC (rms) between any two legs (as you would in single phase)?

The answer is that in 3-phase supplies the voltage between any two legs is represented by a pair of rotating vectors separated by a phase angle of 120 degrees.

Thus V = (Sin 120)(240 VAC) = 208 VAC

Your K-box power supply can easily handle this voltage range and will work like a charm.