Powerware Uninterruptible Power Supply SOLA 4000 - Manual (Page 62)

SOLA 4000 - Operation
JUE 401266 62
3 OPERATING MODES HOT-STANDBY
OPERATION
3.1 Normal Operation
"Normal Operation" is the standard operating mode of the hot-
standby system.
• Mains power is present.
• The rectifiers of all units convert ac power to dc power which
charges the batteries and feeds the inverters.
• The inverters convert this dc power to ac power.
• The inverter of one unit feeds the connected load.
• The inverter of the other unit(s) is working in standby mode,
ready to takeover the load if there is a failure in the unit supply-
ing the load.
• All units in the system are identical and operate completely
independently of each other.
3.2 Operation with an Inverter Failure
"Operation with an Inverter Failure" is the operating mode of the
hot-standby system after a failure has occurred in one unit.
• Mains power is present.
• The static inverter switch of the failed unit opens automatically
and the static inverter switch of an other unit is closed.
• The rectifier of that unit converts ac power to dc power which
charges the battery and feeds the inverter. The inverter then
converts this dc power to ac power used to feed the connected
load.
• The static bypasses within all units remain ready to supply the
load in case of any additional failure(s) or overload.
3.3 Battery Operation
The "Battery Operation" mode is activated by a mains failure or
rectifier failure.
• The rectifiers of all units supply no power.
• The batteries of all units supply the required dc power to the
inverter of each unit.
• The inverter of one unit continues to supply ac power to the
load.
• The inverter(s) of the other unit(s) are operating in standby
mode, ready to takeover the load, without interruption.
3 Operating Modes Hot-Standby Operation