Load Power Factor - Transformer Secondary reflected to Primary

[gar]

171018-0703 EDT

ron:

Why are the servers being powered with AC instead of DC?

A scope should be useful to determine lead or lag. Better would be a phase sensitive meter with recorder to get this information.

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[gar]

171018-1324 EDT

The following link has meters to measure phase angle:

https://www.laurels.com/phase.php?i...MI_qqRm9f61gIVBjFpCh34Jwk0EAAYASAAEgIgQvD_BwE

I know nothing about the company. It just came up from a search.

I believe they use zero crossing information, rather than some sort of integration over a cycle.

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[ron]

171018-1324 EDT

The following link has meters to measure phase angle:

https://www.laurels.com/phase.php?i...MI_qqRm9f61gIVBjFpCh34Jwk0EAAYASAAEgIgQvD_BwE

I know nothing about the company. It just came up from a search.

I believe they use zero crossing information, rather than some sort of integration over a cycle.

.

Thanks, we'll see what appetite the client has to drive the analysis further considering the addition of metering.

I suspect the concern will die away.

 

[Sahib]

I have power meters on the primary side of step down transformers in a data center. The power meter does not indicate leading or lagging, just a absolute value of power factor.

Typically new server power supplies are capacitive and have a leading power factor. I wanted t know if the power factor read on the primary was shifted relative to the secondary. If the power factor on the primary is not shifted, then I will guess the value shown is leading and derate the upstream UPS accordingly (it is unity rated - kw rating equals the kVA rating).

Power factor less than unity, irrespective of leading or lagging, increases current draw from UPS. It may only be necessary to see the product of voltage and current does not exceed the rated VA and the product of current, voltage and absolute value of power factor does not exceed the rated W of UPS.