Output voltage

DOE-SPEC-3021-97

The inrush characteristics must come from an analysis of the loads themselves.

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Output voltage. The UPS inverter shall maintain the output voltage

3.3.2.1

within +[ ] and -[ ]% and output frequency within +[ ] and

-[ ]%, when delivering no load, through rated continuous output of

[ ] kVA at [ ] pf lagging through unity pf with steady-state variation

in normal supply voltage and frequency as specified in paragraph

3.2.1 in any combination, or with variations in the dc power supply

voltage as specified in paragraph 3.3.4.

3.3.2.2

Transient response. Upon sudden application or removal of [ ]%

load in one step, the transient response of the UPS systems (with

transfer switch) shall not permit the voltage to deviate simultaneously

more than +[ ]% (on peak-to-peak measurement basis) and it shall

recover to within +[ ]% of nominal voltage in less than [ ] cycles.

Frequency shall remain within the steady state requirements at all

times (paragraph 3.3.2.1 above).

Harmonic content. The total harmonic content of the UPS inverter

3.3.2.3

output shall be less than [ ]% rms. The content of any single

harmonic shall be less than [ ]% rms.

3.3.2.4

Inrush. The inverter shall tolerate a maximum expected inrush of

[ ] kVA for a duration of [ ] milliseconds at rated voltage and at

[ ] lagging power factor.

ATTENTION:

The term "thermal degradation" means that no components within the system shall suffer any change in

performance due to the worst case operating temperatures in the system while the system is operating within

specified limits.

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3.3.2.5

Operating constraints. The UPS system shall operate continuously

within the specified voltage and frequency limits, from no-load to

full-load conditions without thermal degradation. The UPS system

inverter shall operate within its specified output boundaries when

supplying the inrush load by transferring the inrush demand, if

required, to the internal bypass ac power source through operation

of the transfer switch.

3.3.2.6

Synchronization.

a. The UPS system inverter output shall be frequency and phase

synchronized to the internal bypass source frequency (as

indicated in subparagraph b. below). In the event the Owner's

electrical distribution system frequency is outside the limits given

in paragraph 3.2.1, the inverter shall revert to its own internal

standard which shall maintain the output frequency