Schweitzer Engineering Laboratories SEL-701 - Page 447

Date Code 20010719 701 Motor Protection Relay
Glossary
Instantaneous Meter–Load Profile
GL.5
Instantaneous Meter Type of meter data presented by the SEL-701 Relay
that includes the present values measured at the relay
ac inputs. The word “Instantaneous” is used to
differentiate these values from the measurements
presented by the demand, thermal, energy, and other
meter types.
Key Switch Contact A type of electrical contact that can only be moved
from the open to closed position or back when you
insert the appropriate key and rotate the cylinder.
Learned Motor
Cooling Time
A motor parameter that the SEL-701 Relay can
calculate using data collected over time. In order to
calculate Learned Motor Cooling Time, the relay must
be connected to measure the temperature of an ambient
temperature RTD and at least one RTD embedded in
the motor windings. The relay collects cooling time
data for five consecutive motor stops and, if enabled by
your settings, uses that cooling time in the thermal
model.
Learned Starting
Thermal Capacity
A motor parameter that the SEL-701 Relay can
calculate using data collected over time. In order to
calculate Learned Starting Thermal Capacity, the relay
records the percent of thermal model capacity used
during each of the last five motor starts.
LED Abbreviation for Light-Emitting Diode. Used as
indicator lamps on the relay front panel.
Load Jam Element A motor protection element that, when enabled, can
trip the protected motor if the rotor stops turning due to
a sudden increase in load torque or decrease in bus
voltage. When the rotor stops, the motor phase current
increases. The relay detects the stopped rotor using a
settable overcurrent element and trips after a settable
time-delay.
Load Loss Element A motor protection element that, when enabled, can
trip the protected motor if the motor shaft is suddenly
decoupled from the mechanical load. The relay detects
the sudden decrease in mechanical load using an
undercurrent or underpower element.
Load Profile A function that stores selected relay measurements in
nonvolatile memory every 15 minutes. The relay has
enough memory to store at least 30 days of data before
it replaces the oldest record with the newest one.