Method and device for monitoring the operation of a motor
OwnerWilliam E. Lane, Jr.inventor
Life of this patent
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Abstract
In a method and device for monitoring the operation of a motor, the current drawn by the motor is sensed a preselected time after a peak of current is sensed. This sensed current is then compared to both a minimum and a maximum current threshold value to determine whether the sensed current is inside or outside the range of currents defined by the minimum and maximum current threshold values. The minimum and/or maximum current threshold values are dynamically adjusted as a function of the comparison.
Claims11
A method of monitoring the operation of a motor-driven system, comprising the steps of:
- sensing a current drawn by the motor at a preselected time after starting the motor;
- comparing the sensed current to previously determined minimum and maximum current threshold values which define a range of currents;
- determining that a malfunction has occurred in the system when the current is sensed outside the range of currents;
- adjusting at least one of the minimum and maximum current threshold values as a function of the sensed current;
- and
- storing the adjusted threshold values to be used the next time the preceding steps are carried out.
A device for monitoring the operation of a motor-driven system, comprising:
- means for sensing a current drawn by the motor at a preselected time after starting the motor;
- means for comparing the sensed current to previously determined minimum and maximum current threshold values which define a range of currents;
- means for determining that a malfunction has occurred in the system when the current is sensed outside the range of currents;
- means for adjusting at least one of the minimum and maximum current threshold values as a function of the sensed current;
- and
- means for storing the adjusted threshold values for subsequent use.
A method of monitoring the operation of a motor-driven system, comprising the steps of:
- sensing a current drawn by the motor;
- comparing the sensed current to a previously determined minimum current threshold value;
- timing an interval during which the sensed current is below the minimum current threshold value;
- comparing the interval to a preselected maximum time threshold value;
- determining that a malfunction has occurred in the system if the interval is greater than the preselected maximum time threshold value;
- adjusting the minimum current threshold value as a function of the sensed current;
- and storing the adjusted minimum current threshold value to be used the next time the preceding steps are carried out.
A method of monitoring the operation of a motor-driven system, comprising the steps of:
- sensing a peak current drawn by the motor;
- comparing the sensed peak current to a previously determined maximum current threshold value;
- counting a number of times that the peak current transitions above the maximum current threshold value within a preselected interval of time;
- comparing the count to a preselected maximum count threshold value;
- determining that a malfunction has occurred in the system if the count is greater than the preselected maximum count threshold value;
- adjusting the maximum current threshold value as a function of the sensed current;
- and storing the adjusted maximum current threshold value to be used the next time the preceding steps are carried out.
Dependencies are inferred from the claim text.