Siemens SIPROTEC 7SJ62 Instruction Manual page 240

Functions
Blocking
6-100
the motor currents drop below a programmable minimum current setting (refer to "Cur-
rent Flow Monitoring" in Subsection 6.1.1). For externally-cooled motors, cables, and
transformers, the Nτ )$&725 = .
The thermal overload protection feature may be blocked via a binary input. When
blocking occurs, the thermal image is simultaneously reset.
When motors must be started for emergency reasons, operating temperatures above
the maximum permissible operating temperatures can be allowed by blocking the trip-
ping signal via a binary input. Since the calculated operating temperature may be high-
er than the maximum allowable operating temperature after drop out of the binary in-
put has taken place, the thermal overload protection function features a programma-
ble run-on time interval which is started when the binary input drops out. Tripping will
be defeated until this time interval elapses. On a final note, the binary input used for
emergency starting affects only the tripping signal. There is no effect on the fault con-
dition protocol nor does the thermal image reset.
Figure 6-45 shows the logic diagram for thermal overload protection.
7SJ62 Manual
C53000-G1140-C121-1