[hrmeghwal]

Dual UPS should be used to drive Server and networking equipment load. Both UPS should share load equally in normal operation. But during maintenance or any break-down of one UPS other UPS should be able to take total load. Server will remain on always.
What should be rating of single UPS in terms of kVA if the total load is 95kW ? Or what is criteria for selection of appropriate rating of UPS for a given load ( Say 95kW)?

Thank you.

[tkrussell]

To convert KW to KVA, one method requires the Power Factor of the load be known, as:

KVA=KW/PF,

Or, if you know the total amps per phase, then:

KVA= Amps x Volts / 1000, for single phase, or,
KVA= Amps x (Volts x 1.73) / 1000 for 3 phase.

Assuming a 208 volt 3 phase system, with a 90 PF of the load, then:

KVA= 95/.90
KVA=105.56

Or, assuming 275 amps per phase at 208 volts 3 phase, then,

KVA= 275 x (208 x 1.73) / 1000 = 98.956

I recommend a system this size be 3 phase if at all possible.

This will arrive at the minimum size of each UPS, since each UPS will need to assume all load during a Maintenance Window.

The UPS system should be static sized larger for any additional future load, or be scalable.

I suggest you consult with MGE, Liebert, or Powerware, for advice on a system this size.

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