Schneider Electric 4000 Types of Setpoint-Controlled Relay Functions, Undervoltage, Overvoltage

63230-300-212	Chapter 6—Alarms
April 2001	Setpoint-Controlled Relay Functions

Types of Setpoint-Controlled Relay Functions

This section describes some common motor management functions to which the following information applies:

•Values that are too large to fit into the display may require scale factors. For more information on scale factors, refer to “Changing Scale Factors” on page 191 in Appendix B—Using the Command Interface.

•Relays can be configured as normal, latched, or timed. See “Relay Output Operating Modes” on page 75 in Chapter 5—Input/Output Capabilities for more information.

•When the alarm occurs, the circuit monitor operates any specified relays. There are two ways to release relays that are in latched mode:

—Issue a command to de-energize a relay. See Appendix B—Using the Command Interface on page 181 for instructions on using the command interface, or

—Acknowledge the alarm in the high priority log to release the relays from latched mode. From the main menu of the display, select View Alarms > High Priority Log to view and acknowledge unacknowledged alarms. See “Viewing Alarms” on page 41 for detailed instructions.

The list that follows shows the types of alarms available for some common motor management functions:

NOTE: Voltage base alarm setpoints depend on your system configuration. Alarm setpoints for 3-wire systems are VL-Lvalues while 4-wire systems are VL-Nvalues.

Undervoltage:

Pickup and dropout setpoints are entered in volts. The per-phase undervoltage alarm occurs when the per-phase voltage is equal to or below the pickup setpoint long enough to satisfy the specified pickup delay (in seconds). The undervoltage alarm clears when the phase voltage remains above the dropout setpoint for the specified dropout delay period.

Overvoltage:

Pickup and dropout setpoints are entered in volts. The per-phase overvoltage alarm occurs when the per-phase voltage is equal to or above the pickup setpoint long enough to satisfy the specified pickup delay (in seconds). The overvoltage alarm clears when the phase voltage remains below the dropout setpoint for the specified dropout delay period.

Unbalance Current:

Pickup and dropout setpoints are entered in tenths of percent, based on the percentage difference between each phase current with respect to the average of all phase currents. For example, enter an unbalance of 7% as 70. The unbalance current alarm occurs when the phase current deviates from the average of the phase currents, by the percentage pickup setpoint, for the specified pickup delay. The alarm clears when the percentage difference between the phase current and the average of all phases remains below the dropout setpoint for the specified dropout delay period.

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