9424200996 82-33
BE1-11m Time Curve Characteristics
Thermal Curve (49TC)
The Standard and IEC curves are defined below.
Standard Curve
The Standard Curve Time Dial setting determines the time to trip when the 49TC element is configured
for Standard Curve mode. The standard curve provides a
I
2
curve with a range of time dial settings that
accommodate a wide range of motor timings. The standard curve equation is shown in Equation 82-12.
t = TD × 88.744132 × ln
I
S SF FLA
I
S SF FLA
1
With max value of
I
/(S•SF•FLA) of 10.
Equation 82-12. Standard Curve
Where:
t = Operating time
I
= Measured equivalent motor current
TD
= Time Dial
FLA = Full Load Amps
SF = Service Factor
S = Overload Scaler
ln = Natural log
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