Advanced commissioning
6.21 Monitoring the driven load
Converter with the control units CU240D-2
Operating Instructions, 04/2018, FW V4.9 SP10, A5E34262100B AF
231
Examples:
●
For fans or conveyor belts, an excessively low torque can mean a broken drive belt.
●
For pumps, insufficient torque can indicate a leakage or dry-running.
●
For extruders and mixers, an excessive torque together with low speed can indicate
machine blockage.
Functions for monitoring the driven load
The inverter provides the following means to monitor the driven load via the torque of the
motor:
The stall protection prevents an induction motor from stalling.
The no-load monitoring evaluates the motor current. Insufficient current indicates
that the motor and the load are no longer mechanically connected with each
other.
The blocking protection triggers for a motor current that corresponds to the set
current limit coupled with motor standstill.
The torque monitoring assumes that a specific torque is associated with each
speed for pumps and fans. Insufficient torque indicates that the motor and the
load are no longer mechanically connected.
An excessive torque can indicate problems in the mechanical system of the
driven load, e.g. a mechanically blocked load.
Monitoring the driven load with a binary signal:
The speed monitoring evaluates a periodic binary signal. A signal failure indi-
cates that the motor and the load are no longer mechanically connected with
each other.
