Siemens SIPROTEC 4, User Manual

Page: 146 / 734

[7sj6x_anlaufzeitueberwachung-150502-kn, 1, en_US]
Figure 2-56 Logic diagram of the Motor Starting Protection
Switching of Startup Times
The motor manufacturer provides startup time curves for both cold and warm motor conditions (see
Figure 2-55 ). The function Motor Starting Protection automatically performs a switching. The "warm motor"
condition is derived from the thermal storage of the restart inhibit (see Section 2.8.2 Motor Restart Inhibit 66 ).
Therefore, this function must be enabled. The condition for the switching is determined by the parameter
4106
TEMP.COLD MOTOR
. If the motor temperature (actually the rotor temperature) exceeds the threshold
value, then a switching from "cold motor" to "warm motor" takes place (see Figure 2-56 ). The threshold values
can be derived from the permitted number of cold (n
cold
) and warm (n
warm
) motor startups. By means of the
following formula an approximate limit value can be determined.
(Parameter 4106
TEMP.COLD MOTOR
)
[formel-motoranlauftemperatur-warm, 1, en_US]
The setting value should always be lower than the limit value (see Setting Notes 2.8.1.2 Setting Notes ).
Functions
2.8 Motor Protection
146 SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016