84-18 9424200996
Settings Calculation Examples BE1-11m
User Programmable Alarm 3 is used for reporting a minor alarm, which indicates a large percentage
restraint imbalance during starting mode. Use the Settings Explorer to navigate to Alarm Configuration,
User Programmable Alarms, and name User Programmable Alarm 3 to “Differential Slope”. Navigate to
Alarm Configuration, Alarms, and enable Programmable Alarm 3 as a minor alarm. This alarm will show
up in the sequence of events and alarm reporting as “Differential Slope”.
Figure 84-22. Protection, Current, Current Differential (87) Screen
Instantaneous Undercurrent (37) - Loss of Load Protection
The 37 element protects the motor from overheating by tripping when a load or shaft coupling is lost and
motor current drops. The 37 element protects only when the motor is in running mode and can be set to
trip on a loss of load condition, especially for pump motors where flowing water cools the motor. For
pumps, a loss of current would indicate less cooling. The pickup setting is calculated in Equation 84-16.
= 75%
= 0.75 4.54 = 3.405
Equation 84-16. 37 Pickup
Select three-phase mode, set the pickup setting to 3.405 Secondary A, and set the time delay to 100 ms
as shown in Figure 84-23.
Figure 84-23. Protection, Current, Instantaneous Undercurrent (37) Screen
Protection - Voltage
Two undervoltage protection elements are used to monitor undervoltage conditions.
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