●
Why use a UPS?
Use a UPS for a fully loaded workstation configuration that operates in a poor power grid area.
The UPS must be rated for at least 2 kVA. A UPS is necessary because without line conditioning to
guarantee greater than 90 volts for 1110 or 1125 watts output and 105 volts for 1250 or 1275
watts output, the maximum output power is limited to 890 watts and 1110 or 1125 watts,
respectively. See
Power dissipation for the HP Z800 Workstation on page 4 for configurations
and maximum power estimates.
HP recommends an online continuous UPS that provides a layer of insulation from quality
problems. This type of supply also allows control of output voltage and frequency regardless of
input voltage and frequency. To reach 1250 or 1275 watts of output power, you must maintain
115 volts, ideally.
●
To reduce the risk of overload:
◦
Do not exceed the rated load of any single power distribution unit (PDU).
◦
Do not load a single National Electrical Manufacturers Association (NEMA) 5 to 15
receptacle with more than 15 amps.
◦
Do not load a single International Electrotechnical Commission (IEC) 320-1/C13 receptacle
with more than 10 amps.
◦
In general, verify that each power source circuit can safely provide the current required by
equipment drawing power from it.
Input current calculation
The 1110W power supply can provide 1110 watts in a 15A circuit by using this input current
calculation:
Input Current = Output Power / (Voltage x Power
Factor x Efficiency)
Workstation HP Z800 HP Z820
Output Power = 1110 watts 1125 watts
Voltage = 90 volts 90 volts
Power Factor = 0.998 0.998
Efficiency = 0.82 0.835
In this formula, the voltage (90 volts) includes all power line
variations—line voltage sag, brownout conditions, power grid
characteristics, and so on.
CAUTION: Check with your power provider to see if your facility is exposed to 90V power. If 90
volts cannot be guaranteed to your workstation, the input voltage source might blow the fuse in the
power supply or trip the breaker.
For reliable workstation operation under heavy loading, use a UPS because it provides reliable voltage
levels.
Input current calculation
3
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