Schweitzer Engineering Laboratories SEL-701-1, Instruction Manual

Page: 83 / 452

Date Code 20011009
SEL-701-1 Monitor
Settings Calculation
Basic Motor Protection
3.25
Load-Loss Elements
Load-Loss Element, No Voltage Option (Monitor Models 0701100X & 0701110X)
When the monitor is not equipped with optional voltage inputs, the load-loss
detection function is dependent on current alone. The monitor arms the load-loss
detection logic a settable time after the motor starts, as defined by the Load Loss
Starting Time Delay setting. Set this delay to allow pumps or compressors to reach
normal load. Once armed, the function issues an alarm or trip if phase current drops
below the alarm or trip threshold for the specified time delay.
Set the Load Loss Trip and Alarm thresholds greater than the expected motor no
load current but less than the minimum current expected when the motor is operating
normally. These settings are entered in per unit of the Full Load Amps (FLA) setting.
If you expect the motor to operate at no load normally, disable this function by
setting LLAPU equal to OFF. The monitor automatically hides the remaining load-loss
settings.
Table 3.17 Load-Loss Element Settings, No Voltage Option
Setting Prompt Setting Range
Setting Name =
Factory Default
Load Loss Alarm Threshold OFF, 0.10–1.00 pu FLA LLAPU = OFF
Load Loss Trip Threshold 0.10–1.00 pu FLA LLTPU = 0.50
Load Loss Starting Time Delay 0–15000 s LLSDLY = 0
Load Loss Alarm Time Delay 0.00–400.00 s LLADLY = 5.00
Load Loss Trip Time Delay 0.00–400.00 s LLTDLY = 10.00