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HT33 Series User Manual
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.
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.
3.2.8 Parallel connection redundancy mode
Several single UPS devices may be parallel connected directly and the parallel operation control
logic in single UPS devices ensures all single device automatically average 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
