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3.2.1 Normal Mode
The UPS inverter power modules continuously supply the critical AC load. The rectifier/charger derives power from
the AC mains input source and supplies DC power to the inverter while simultaneously FLOAT or BOOST charging its
associated backup battery.
3.2.2 Battery Mode
Upon failure of the AC mains input power; the inverter power modules, which obtains power from the battery,
supplies the critical AC load. There is no interruption in power to the critical load upon failure. After restoration of the AC
mains input power, the “Normal Mode” operation will continue automatically without the necessity of user intervention.
Note: UPS can also be started through battery mode via battery cold start function upon failure of the AC mains.
Therefore, the battery power can be used independently to improve the utilization rate of UPS.
3.2.3 Auto-Restart Mode
The battery may become exhausted following an extended AC mains failure. The inverter shuts down when the
battery reaches the End of Discharge voltage (EOD). The UPS may be programmed to “Auto Recovery after EOD” after
a delay time if the AC main recovers. This mode and any delay time are programmed by the commissioning engineer.
During the process of delay time, the battery will be charged by UPS to prevent any risks to load equipment from
future mains failure.
3.2.4 Bypass Mode
If the inverter overload capacity is exceeded under normal mode, or if the inverter becomes unavailable for any
reason, the static transfer switch will perform a transfer of the load from the inverter to the bypass source, with no
interruption in power to the critical AC load.
3.2.5 Maintenance Mode
A manual bypass switch is available to ensure continuity of supply to the critical load when the UPS becomes
unavailable e.g. during a maintenance procedure.
It is noticed that after UPS system supplies the power with the bypass mode, the maintenance bypass rotary switch
Q3, in this situation is closed Q1, Q2, Q3-2 out put contacts and battery switches are disconnected.
Warning: Hazard may occur after transferring to maintenance bypass
After UPS being transferred to maintenance bypass, UPS battery, input and output terminals and are
charged.
3.2.6 ECO Mode
If economical (ECO) mode is selected, the double-conversion UPS will stop to work so as to save energy. During the
operation of ECO mode, the load power will be supplied by bypass preferentially. When bypass power is within the range
of normal frequency and voltage, load power will be supplied by bypass, or the system will transfer to inverter output,
followed by load power interruption which extends within 3/4 of the period. E.g. when the frequency is 50Hz, the
interruption time will be less than 15ms; when the frequency is 60Hz, the time will be less than 12.5ms.
Eco mode have to set by customer service
3.2.7 Frequency Converters Mode
If the frequency converter configuration is used by UPS, it will provide 50Hz or 60Hz stable output frequency. The
range of output frequency is 40Hz-70Hz. Under this mode, static bypass is unavailable, but battery can be selected
according to the actual requirements of battery mode.
Frequency Converte Mode have to set by customer service
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3.2.8 Parallel connection redundancy mode
Several UPS devices may be parallel connected directly and the parallel operation control logic in single UPS
devices ensures all single device automatically share the load to improve the capacity or reliability of the system, or both
the capacity and reliability of the system. The capacity of a parallel operation system can be up to 6 units.
3.3 Battery Management
3.3.1 Normal Function
The following functions should be fitted by commissioning engineers with specified software.
1.
Constant current boost charging
Current can be set up
2.
Constant voltage boost charging
Voltage of boost charging can be set as required by the type of battery.
For Valve Regulated Lead Acid (VRLA) batteries, maximum boost charge voltage should not exceed 2.4V / cell.
3.
Float charge
Voltage of float charging can be set as required by the type of battery.
For VRLA, float charge voltage should be between 2.2V to 2.3V.
4.
Float charge temperature compensation (optional)
A coefficient of temperature compensation can be set as required by the type of battery.
5.
End of discharge (EOD) protection.
If the battery voltage is lower than the EOD, the battery converter will shut down and the battery is isolated to avoid
further battery discharge. EOD is adjustable from 1.6V to 1.75V per cell (VRLA) or 0.9 to 1.1 V per cell
6.
Battery low warning time
It is adjustable between 3 and 60 minutes. The default is 5 minutes.
3.3.2 Advanced Functions (Battery Self-checking and Maintenance)
At periodic intervals, 20% of the rated capacity of the battery will be discharged automatically, and the actual load
must exceed 20% of the rated UPS (KVA) capacity. If the load is less than 20%, auto-discharge cannot be executed. The
periodic interval can be set from 30 to 360 days. The battery self-test can be disabled.
Conditions—Battery at float charge for at least 5 hours, load equal to 20~100% of rated UPS capacity
Trigger—Manually through the command of “Battery Maintenance Test” in LCD panel or automatically
3.4 Battery Protection
The following functions should be fitted by commissioning engineers with specified software.
1.
Battery Low Pre-warning
The battery undervoltage pre-warning occurs before the end of discharge. After this pre-warning, the battery should
have the capacity for 3 remaining minutes discharging with full load. The time is user configured from 3 to 60 minutes.
2.
Battery discharge (EOD)off protection
If the battery voltage is lower than the EOD, the battery converter will be shut down. EOD is adjustable from 1.6V to
1.75V per cell (VRLA) or 0.9 to 1.1 V per cell (NiCd)
3.
Battery Circuit Breaker (BCB) Alarm (Optional)
The alarm occurs when the battery disconnect device disconnects. The external battery connects to the UPS
through the external battery circuit breaker. The circuit breaker is manually closed and tripped by the UPS control circuit.
See relay card optionals
