Functions
5.8 Protection functions
5.8.4
Load torque monitoring (system protection)
Applications with load torque monitoring
In many applications, it is advisable to monitor the motor torque:
● Applications in which the mechanical connection between the motor and load may be
● Applications that are to be protected against overload or locking (e.g. extruders or
● Applications in which no-load operation of the motor represents a critical situation (e.g.
Load torque monitoring functions
The inverter monitors the torque of the motor in different ways:
1. No-load monitoring:
2. Lock protection:
3. Stall protection:
4. Frequency-dependent torque monitoring:
122
interrupted (e.g. if the drive belt in fan or conveyor belt systems tears).
mixers).
pumps).
The inverter generates a message if the motor torque is too low.
The inverter generates a message if the motor speed cannot match the speed setpoint
despite maximum torque.
The inverter generates a message if the inverter control has lost the orientation of the
motor.
The inverter measures the current torque and compares it with a parameterized
frequency/torque characteristic.
CU240S and CU240E Control Units, FW 3.2
Operating Instructions, 03/2009, A5E02440075B AA