Schweitzer Engineering Laboratories SEL-701 - Table 4.5; Thermal Element Configuration Settings, Setting Method = RATING

Date Code 20010719 701 Motor Protection Relay
Settings Calculation
Basic Motor Protection
4.9
Thermal Element RATING Setting Method
Table 4.5 Therma l Element Configu ration Setting s, Setting Method = RATING
When you select the RATING thermal element setting method, the relay requests
information on the protected motor capabilities. Obtain all of the requested information
except the Locked Rotor Trip Time Dial from the motor specifications.
Occasionally, only one locked rotor time will be specified for a particular motor.
Unless the specification states otherwise, assume the time is the cold locked rotor time.
Multiply the cold locked rotor time by 0.833 to determine a hot locked rotor time that
is acceptable for most motors. If only the hot locked rotor time is specified, multiply
that value by 1.2 to determine a cold locked rotor time that is acceptable for most
motors.
Table 4.5
Thermal Element
Configuration Settings, Setting Method = RATING
Setting Prompt Setting Range Setting Name = Factory Default
Setting Method
Rating,
Generic, User
SETMETH = RATING
Full Load Amps 1.00–8.00 A
ITAP = 5 A
0.20–1.60 A
a
ITAP = 1 A
FLA = 5.00
FLA = 1.00
Service Factor 1.00–1.50 SF = 1.15
Locked Rotor Amps 2.50–80.00 A
ITAP = 5 A
0.50–16.00 A
a
ITAP = 1 A
LRA = 30.00
LRA = 6.00
Hot Locked Rotor Time 1.0–200.0 s LRTHOT = 2.1
Cold Locked Rotor Time 1.0–240.0 s LRTCOLD = 2.5
Locked Rotor Trip Time Dial 0.10–1.50 TD = 1.00
a
The range of the Full Load Amps and Locked Rotor Amps settings depends on the ITAP
setting as shown.