Power Meter Bulletin No. 3020IM9503R6/98
Chapter 9—Onboard Alarming December 1998
68 1998 Square D All Rights Reserved
Undervoltage
• Pickup and dropout setpoints are entered in volts. Very large values may
require scale factors. Refer to Appendix I—Alarm Setup.
• The per-phase overvoltage alarm occurs when the per-phase voltage is
equal to or above the pickup setpoint for the specified pickup delay period
(in seconds).
• When the overvoltage alarm occurs, the power meter operates the KYZ
output (if the output is enabled).
• The relay remains closed until the overvoltage alarm clears. The 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 16.0%
as 160.
• 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 (in seconds).
• When the unbalance current alarm occurs, the power meter operates the
KYZ output (if the output is enabled).
• The relay remains closed until the unbalance current alarm clears. 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.
Unbalance Voltage
Pickup and dropout setpoints are entered in tenths of percent, based on the
percentage difference between each phase voltage with respect to the average
of all phase voltages. For example, enter an unbalance of 16.0% as 160.
• The unbalance voltage alarm occurs when the phase voltage deviates from
the average of the phase voltages, by the percentage pickup setpoint, for
the specified pickup delay (in seconds).
• When the unbalance voltage alarm occurs, the power meter operates the
KYZ output (if the output is enabled).
• The relay remains closed until the unbalance voltage alarm clears. The
unbalance voltage alarm clears when the percentage difference between
the phase voltage and the average of all phases remains below the dropout
setpoint for the specified dropout delay period.
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