Siemens SIPROTEC 4 User Manual page 152

Functions
2.8 Motor Protection
further details, see
type increased safety
Emergency Start
If, for emergency reasons, motor starting that will exceed the maximum allowable rotor temperature must
take place, the motor restart inhibit signal can be removed via a binary input (
allowing a new starting attempt. The thermal rotor profile, however, continues to function and the maximum
allowable rotor temperature will be exceeded. No motor shutdown will be initiated by the motor restart
inhibit, but the calculated excessive temperature of the rotor can be observed for risk assessment.
Blocking
If the motor restart inhibit function is blocked via binary input
of the rotor overtemperature, the equilibrium time T Equal and the minimum inhibit time T MIN.
INHIBIT are reset. Thus any blocking signal that is present or upcoming is disregarded.
Via another binary input (
useful for testing and commissioning, and after a power supply voltage failure.
Logic
There is no pickup annunciation for the restart inhibit and no trip log is produced. The following figure shows
the logic diagram for the restart inhibit.
152
/5/ Additional description for the protection of explosion-protected motors of protection
"e".
>66 RM th.repl. ) the thermal replica can be reset independently. This may be
>66 emer.start ), thus
>BLOCK 66 or switched off, the thermal replica
SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016