S4K2U-5C SERIES USER MANUAL |
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1.4.3 Inverter
In normal operation, the S4K2U-5C’s inverter utilizes the dc output of the PFC rectifier to produce precise, regulated sine
wave ac power. When mains power fails, the inverter receives dc power from the dc-to-dc converter. In either operation
mode, the UPS inverter is on-line, continuously generating clean, precise, regulated ac output power.
1.4.4 Battery Charger
The battery charger utilizes energy from the mains power and precisely regulates it to continuously float charge the
batteries. The batteries are being charged whenever the S4K2U-5C is plugged in, even when the UPS is not turned on.
1.4.5 Dc-to-Dc Converter
The dc-to-dc converter raises the dc voltage from the battery to the optimum operating voltage for the inverter. This
allows the inverter to operate continuously at its optimum efficiency and voltage, thus increasing reliability.
1.4.6 Battery
The S4K2U-5C uses valve-regulated, non-spillable, lead acid batteries. To maintain battery design life, operate the UPS in
an ambient temperature of 0°C to 25°C (32°F to 77°F).
NOTE:
Optional external battery cabinets are available to extend battery run times.
1.4.7 Dynamic Bypass
The S4K2U-5C provides an alternate path for mains power to the connected loads in the unlikely event of a UPS malfunc-
tion. Should the S4K2U-5C have an overload, overtemperature, or UPS failure condition, the UPS automatically transfers
the connected loads to bypass.
NOTE:
The bypass power path does not protect the connected loads from disturbances on the mains.
1.5 Operating Modes
The UPS operating modes include: Mains (V ac) Mode, Bypass Mode, Battery Mode, Battery Recharge Mode, and
Frequency Converter Mode. For descriptions of indicators and control buttons, refer to “3.0 Controls & Indicators”.
1.5.1 Mains (V ac) Mode
During Mains (V ac) Mode, mains power provides energy to the S4K2U-5C. The filters, PFC rectifier, and the inverter
process this power to provide computer-grade power to connected loads. Meanwhile, the UPS maintains the batteries in
a fully charged state.
1.5.2 Manual Bypass Mode
Manual Bypass Mode occurs when the Standby/Manual Bypass button is pressed and held for about 2 seconds while
the S4K2U-5C is in Mains (V ac) Mode. Bypass operation is indicated by an audible alarm and illuminated amber bypass
indicator. (If other indicators are illuminated, refer to “8.0 Troubleshooting”). During Manual Bypass Mode, mains power
bypasses the inverter and provides energy to the connected load.
!
CAUTION
Turning off the UPS in Manual Bypass Mode will result in loss of output power and dropped loads.
