Brake torque monitoring and health assessment
AssigneeOtis Elevator Company
InventorsJames L. Hubbard, Michael Garfinkel, Juan Antonio Illan, Robert D. Shepherd
Life of this patent
Estimating the term…
Abstract
A method for monitoring brake torque of an elevator having a motor is provided. The method may engage an elevator brake for a predefined duration, determine a displacement of an output shaft of the motor during the predefined duration, and generate an alert if the displacement exceeds a predefined threshold.
Claims17
A method for monitoring brake torque of an elevator having a motor, the method comprising:
- engaging an elevator brake;
- determining a minimum motor current required to drive an output shaft of the motor through the brake while engaging the brake;
- computing a baseline brake torque based at least partially on the minimum motor current;
- periodically monitoring the brake torque for any significant decrease as compared with the baseline brake torque;
- and
- generating an alert if a subsequently computed brake torque is determined to be less than a predefined fraction of the baseline brake torque.
A method for monitoring at least one brake of an elevator having a motor, the method comprising:
- during a brake calibration, engaging the brake and determining a minimum motor current required to drive an output shaft of the motor through the engaged brake;
- during a brake test, applying a test motor current to the motor while engaging the brake, the test motor current being a fraction of the minimum motor current;
- determining a displacement of the output shaft;
- and
- generating an alert if the displacement exceeds a predefined threshold.
A brake monitoring system for an elevator, the brake monitoring system comprising:
- a motor having an output shaft;
- an encoder configured to detect displacement of the output shaft;
- at least one brake configured to selectively engage the output shaft;
- a controller in communication with each of the motor, the encoder, and the brake, the controller configured to engage the brake and determine a minimum motor current required to drive the output shaft through the engaged brake during a brake calibration, apply a test motor current being a fraction of the minimum motor current to the motor during a brake test, monitor the encoder for any displacement of the output shaft, and generate an alert if the displacement exceeds a predefined threshold.
A brake monitoring system for an elevator, comprising:
- a motor having an output shaft;
- an encoder configured to detect displacement of the output shaft;
- at least one brake configured to selectively engage the output shaft;
- a controller in communication with each of the motor, the encoder, and the brake, the controller configured to engage the brake and determine a minimum motor current required to drive the output shaft through the engaged brake during a brake calibration, apply a test motor current being a fraction of the minimum motor current to the motor during a brake test, monitor the encoder for any displacement of the output shaft, and generate an alert if the displacement exceeds a predefined threshold;
- wherein the controller computes a baseline brake torque based at least partially on the minimum motor current, and periodically monitors the brake torque for any significant decrease as compared with the baseline brake torque.
Dependencies are inferred from the claim text.