UPS Characteristics
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(1) During normal operation
During normal periods, the UPS converts AC power from the
utility power source into DC power through the rectifier, and
reconverts this DC power back into AC power through the
inverter and supplies it to the load. The output power is
stable AC power synchronized with the utility power source.
The batteries are kept continually charged by the charger
and ready in case a problem (power outage or voltage drop)
occurs with the utility supply.
(2) When utility power fails
When a failure or power outage occurs at the utility power
source, the rectifier and charger stop operating while
inverter operation continues, now using the batteries as a
DC source, to ensure stable power supply to the load without
even a momentary power dropout. At the same time, the
buzzer sounds and “Green
INPUT
” starts blinking.
(3) When battery voltage drops
When a failure or power outage at the utility power source continues, the battery voltage drops to approximately
178 V or less, the buzzer sounds and “
Batt Vol Low
” is displayed on the LCD screen.
(4) When utility power recovers
When normal utility power is restored, rectifier and charger operations resume, automatically returning to the normal
operation state described in 12.1 (1).
(5) Extended power outage.
If a power outage persists and the battery voltage reaches the final discharge level of approximately 168 V, a
protective circuit shuts off the inverter to prevent over-discharging of the batteries. When normal utility power
recovers after the inverter has been stopped, operation is automatically resumed*, returning to the normal operation
state described in 12.1 (1).
* When “UPS Operation Upon Power Recovery” in the LCD panel setting menu is set to “STOP,” inverter output
remains stopped.
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(1) Overload protection
If the UPS output is overloaded by the current capacity of the
inverter being exceeded, such as when a computer system boots up,
the output selector automatically switches the source of power from
the inverter to bypass circuit without interruption. Once the
overload state is resolved, the source of power is switched to the
inverter, and operation returns to the normal operation state.
* When “Overload Recovery Operation” in the LCD panel setting
menu is set to “Auto Ret BYP,” the UPS switches the source of
power to the inverter without interruption after a set period of
time has elapsed, and operation returns to the normal
operation state.
(2) UPS Unit failure protection
In the unlikely event a failure occurs in the UPS, the unit in which the
failure occurred is cut off automatically, and inverter power supply is
continued from the normally operating unit. At the same time, “Red
WARNING
” on the LCD panel and the “Red
ALARM
” LED on the UPS Unit
control panel of the malfunctioned UPS Unit turn on, and the buzzer
sounds.
One of the following occurs depending on the size of the load current.
①
If the load current does not exceed the total current of the
normally operating unit, inverter power supply is continued.
②
If the load current exceeds the total current of the normally
operating unit, the source of power is switched form inverter
power to bypass operation.
The operation becomes the same as that indicated by the
asterisk (*) mark in §12.2 (1) above in accordance with the LCD
panel setting menu.
Utility
power
Batteries
Output
O
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Rectifier
(converter)
Charger
Inverter
Utility
power
Output
Rectifier
(converter)
Charger
Inverter
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Batteries
Utility
power
Output
Rectifier
(converter)
Charger
Inverter
Out
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Batteries
Utility
power
Output
UPS unit No.2
Malfunctioned unit
UPS unit No.1
