S&C Instruction Sheet 653- 502
27
Operation
States
Listed in Table 2 are the states of the PureWave UPS System. Depending on the alarm
condition encountered, the system can be in any of these states. The user interface shall
inform the user of the system’s current state. Table 2 notes the description of each state.
States
Description
Ready
In this state, the PureWave UPS System is ready to protect the load in the event of a disturbance.
Run
In this state, the PureWave UPS System is running to protect the load from a utility disturbance. The inverters are on and the PES is open.
Inhibit
In this state, the PureWave UPS System has been inhibited from running; however, the load is being fed through the PES. The bypass
circuit remains open.
Bypass
In this state, the bypass circuit breaker has been closed; however, the input and output circuit breakers remain closed.
Bypass Isolate
In this state, the bypass circuit breaker is closed, and the input and output circuit breakers are open.
Test in Bypass
This state is used during the startup of the PureWave UPS System or during service. The state permits the system to perform runs while
the load is being fed from the utility through the bypass circuit breaker. In this state, the bypass circuit breaker is closed and the output
circuit breaker is open.
Table 2. Operating States for the PureWave UPS System.
Transition States
Listed in Table 3 are the transition states of the PureWave UPS System. These temporary
states occur while the PureWave UPS control logic is transitioning from one primary state
to another primary state. Primary states are listed in Table 2.
Transition States
Description
Reset
This state is used to reset PureWave UPS System alarms.
Force Off PES
This state is used to command the PES off. The PES remains off for the duration of the
Run state, keeping the load isolated from the
utility.
Close Mechanical
Bypass
This state occurs as the PureWave UPS System is going to the
Bypass state. During this transition state, the controls are commanding
the bypass circuit breaker closed before transitioning to the
Bypass state.
Soft Transfer
The PureWave UPS System enters this state at the end of a
Run state. In this state, the load is being transferred to the utility or
generator gradually to prevent a voltage or frequency drop that could potentially affect the load.
Load Decelerate
This is an optional state that will disconnect the load from the utility if the PureWave UPS System cannot run (because of discharged
batteries or from a UPS malfunction) and if the load is not in phase with the utility. The purpose of this state is to prevent spinning
loads (motors) from being damaged by transferring them from the PureWave UPS System to the utility when the UPS output voltage is
not in phase with the utility voltage. The loads will be permitted to decelerate before being re-energized.
Table 3. Transition states of the PureWave UPS System.
