SEAL 7S8758 - Caterpillar

The UPS functions automatically in order to supply AC electrical power to the critical load. There are several operation modes that allow the UPS to accomplish this task. Most of the operating modes have several states that occur in that mode. The mode and the state are displayed on the LCD display. The LCD display is located on the front panel. The operating modes are listed below:
On-line Modes
Bypass Modes
Automatic Voltage Regulation ModeThe UPS continually monitors internal systems and the incoming utility power. The UPS will automatically change between the modes, as required. The change is accomplished with no intervention by an operator. The detection logic and the switching logic inside the UPS ensures that the changes in the operating mode are automatic and transparent to the critical load.A computer connected with an RS-232 cable allows system monitoring with optional UPS monitoring software. The cable is connected to the RS-232 port located in the system cabinet of an MMS system.On Line Modes
Illustration 1 g02849139
System online mode power flow
Online mode
When operating in the Online mode, the system is ready to protect the load.When the system is in the "Online Mode", the input and output contactors are closed and the bypass breaker is open. Power flow through the system is via the input contactor, the line static switch, the line inductor, and the output inductor. The utility inverter is on.Online mode is the standard operating mode for the system. When the system is in this mode, the load is protected. The system has the capability of discharging to support the load.On Line Charging
The system enters this state when the flywheel reaches 4000 RPM and there is enough stored energy in the flywheels to support the load. The flywheels have not yet reached standby speed. The system can sustain discharge in this state.On Line Standby
When the system flywheel reaches the nominal speed of 7700 RPM, the system is in the Online (standby) state. The UPS is regulating voltage and ready to discharge the flywheels to protect the load. 7700 rpm is the rated idle speed for the flywheel.On Line Discharging
Illustration 2 g02849150
Online discharging mode
The system enters the online discharging state when the unit is supplying power to the load. If power is disrupted, the system changes to this state.Bypass Modes
Illustration 3 g02849186
System bypass mode power flow automatic voltage regulation (AVR) mode
Repeated errors that cause the system to move between the bypass mode and online mode can lock the system into the bypass mode. When the system is locked in the bypass mode, the user must change the mode of the system via the key switch or UPSView.Bypass Mode - Bypass Mode directly connects the incoming utility power to the critical load while bypassing the UPS system. The load is not protected when the UPS is in "Bypass Mode". The load can be affected by a disruption of the incoming power.The bypass circuit also provides a path for power directly from an alternate AC source.The system enters "Bypass Mode" at through one of the following events:
Start-up
The