84-8 9424200996
Settings Calculation Examples BE1-11m
Figure 84-9. Programmable Inputs, Remote RTD, RTD Block Configuration Screen
Protection - Thermal
Thermal Curve (49TC)
The 49TC element is the heart of the BE1-11m Motor Protection System. This equivalent current-based
element models the thermal capacity in the motor by using negative-sequence current, reduced voltage
(when custom curves are used), and RTD biasing (when a remote module is used).
Use the Settings Explorer in BESTCOMSPlus to open the Protection, Thermal, Thermal Curve (49TC)
screen and configure the following settings. See Figure 84-10.
Figure 84-10. Protection, Thermal, Thermal Curve (49TC) Screen
• Mode - Standard Curve is used in this example.
• K - The thermal model operates from equivalent motor current. The K setting determines how much
the negative-sequence current biases the effective current. K is used to determine the equivalent
current as shown in Equation 84-3. To match NEMA MG-1 standards, use a K factor of 8, unless
otherwise specified.
=
1 +
Equation 84-3. Equivalent Current
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