Apparatus and method for testing electric motors
First Claim
1. An apparatus for testing electric motors, comprisinga rotatable member adapted to be coupled to a rotating output member of an electric motor,a first accelerometer carried with the rotatable member in a position to generate output signals corresponding to at least the acceleration of the rotatable member in angular direction,a processor for evaluating the accelerometer output signals anda communication path interconnecting the accelerometer and the processor,a second accelerometer fixed to a stationary part of said electric motor.
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Abstract
To improve the recognition of defective electric motors, the present invention proposes a test apparatus and method comprising an accelerometer mounted on a member rotating with the output shaft of the motor under test. The accelerometer measures the acceleration in the direction of rotation. A communication path between the accelerometer and an electronic processor is provided to assign detected disturbances to certain known defect modes which have been obtained from sample defect motors. The communication path may comprise a slip ring contact.
The rotating accelerometer can detect disturbances caused by gear train defects that cannot be discovered by an accelerometer mounted on the motor housing in the known way.
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Citations
12 Claims
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1. An apparatus for testing electric motors, comprising
a rotatable member adapted to be coupled to a rotating output member of an electric motor, a first accelerometer carried with the rotatable member in a position to generate output signals corresponding to at least the acceleration of the rotatable member in angular direction, a processor for evaluating the accelerometer output signals and a communication path interconnecting the accelerometer and the processor, a second accelerometer fixed to a stationary part of said electric motor.
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7. A method for testing an electric motor with a rotating output member, comprising the following steps:
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measuring the acceleration of the output member at least in angular direction, evaluating the measured acceleration by considering deviations from a predetermined behavior of at least one of the following quantities related to the acceleration;
acceleration, velocity and displacement, whereinthe predetermined behavior for the acceleration in angular direction is defined by a constant value equal to zero. - View Dependent Claims (8, 9, 10, 11)
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12. A method for testing an electric motor with a rotating output member, comprising the following steps:
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measuring the acceleration of the output member at least in angular direction, evaluating the measured acceleration by considering deviations from a predetermined behavior of at least one of the following quantities related to the acceleration;
acceleration, velocity and displacement, whereinadditionally the acceleration in radial direction respective to the rotation is measured and the predetermined behavior for the radial acceleration is defined by a constant value equal to the centripetal acceleration corresponding to the current angular velocity of the rotating member and the distance between the center of rotation and the place of measurement.
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Specification