Load Monitor
First Claim
1. A method for monitoring the load of a motor, comprising the acts of:
- repeatedly measuring the torque and registering the speed during normal operation,determining, in connection with each measurement of the torque during normal operation, a load limit value valid for the registered speed, the load limit value being a function of a plurality of stored torques and speeds and a predetermined deviation value,comparing, in connection with each measurement of the torque during normal operation, the measured torque with the determined load limit value, andgenerating an action signal, if the measured torque is not within an acceptable range limited by the determined load limit value.
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Accused Products
Abstract
A load monitor for monitoring the load of a motor comprises a Central Processing Unit (CPU) and a memory. During normal operation of the motor, the load monitor is arranged to repeatedly measure the torque and registering the speed of the motor. In connection with each measurement of the torque and registering of the speed, the load monitor determines a load limit value valid for the registered speed, which load limit value is a function of a plurality of torques and speeds and a predetermined deviation value stored in the memory. The measured torque is then compared with the determined load limit value and if the measured torque is not within an acceptable range limited by the determined load limit value then an appropriate action is taken.
54 Citations
20 Claims
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1. A method for monitoring the load of a motor, comprising the acts of:
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repeatedly measuring the torque and registering the speed during normal operation, determining, in connection with each measurement of the torque during normal operation, a load limit value valid for the registered speed, the load limit value being a function of a plurality of stored torques and speeds and a predetermined deviation value, comparing, in connection with each measurement of the torque during normal operation, the measured torque with the determined load limit value, and generating an action signal, if the measured torque is not within an acceptable range limited by the determined load limit value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 17, 20)
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13. A method for initiating monitoring and for monitoring the load of a motor, comprising the acts of:
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entering initiating sequence, setting, during the initiating sequence, a first speed for the motor, measuring, after the act of setting a first speed, a torque of the motor, storing the measured torque and the value of the corresponding speed in a memory, setting a second speed for the motor after storing the previously measured torque and the value of the corresponding speed, repeating the acts of measuring and storing for the new speed, shifting to normal operation when initiating sequence is completed, and monitoring a present torque of the motor at a present speed during the normal operation and relating the present torque to the torques and corresponding speeds stored during the initiating sequence in order to decide whether or not the present torque at the present speed is within an acceptable torque range. - View Dependent Claims (14)
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15. A load monitor for monitoring the load of a motor, comprising
a Central Processing Unit (CPU), means for automatically and repeatedly generating a signal for changing the speed of the motor during an initiating sequence, an input for a signal representing the torque, an input for a signal representing the speed, a memory for storing a plurality of measured torques and corresponding speeds during the initiating sequence, means for repeatedly, during normal operation, comparing an input signal representing the torque with a load limit value valid for a speed given by the input signal representing the speed, and means for providing a load limit value, the load limit value being a function of the plurality of torques and speeds stored in the memory and a predetermined deviation value.
Specification