Siemens Simodrive 611 Configuration Manual page 307

8 Important Circuit Information
8.12 Induction motor operation
Overload
protection
8-306
Individual thermal monitoring functions must be provided for overload protection
of the individual induction motors. We recommend that the motor is monitored
using a PTC thermistor temperature sensor (embedded in the motor) and a
3RN1 thermistor motor protection evaluation unit.
If motor feeder cables have to be protected where the rated drive converter cur-
rent is significantly greater than the rated motor current then this must be imple-
mented outside the drive converter.
Notice
Motors may only be changed over using the power contactors in the motor
circuit when terminal 663 – pulse enable/start inhibit – is inhibited
(de–energized). This means that the power contactor may only be switched
when the motor circuit is in a no–current condition.
For additional information also refer to circuit examples =9 in Section 9.7
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
© Siemens AG 2012 All Rights Reserved
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