SYSTEM AND METHOD FOR LIMITING VIBRATION OF ELECTRIC MOTOR
First Claim
1. An electric motor system for limiting a vibration of an electric motor, the electric motor system comprising:
- the electric motor, including a shaft configured to drive a load;
a motor control subsystem configured to control operation of the electric motor, including running the electric motor in accordance with a command specifying a speed or torque at which the electric motor is to be run;
a vibration sensor configured to sense a characteristic of a vibration of the electric motor;
an electronic control element configured to receive data from the vibration sensor regarding the characteristic of the sensed vibration, determine whether the characteristic of the sensed vibration exceeds a pre-determined limit, and if so, reduce the speed of the electric motor to reduce the vibration of the electric motor below the pre-determined limit; and
an electronic memory element configured to store the pre-determined limit used by the electronic control element.
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Accused Products
Abstract
A system and method for limiting the vibration of an electric motor so as to avoid situations in which extreme vibration may result in damage to the motor or other equipment. A motor control subsystem runs the motor in accordance with a command specifying a speed or torque. A vibration sensor, such as a three-axis accelerometer, senses a vibration of the electric motor, or, alternatively, software indirectly detects the vibration based on phase or torque ripple. Such vibration may be caused by, e.g., a broken fan blade or an accumulation of snow or ice. A control element receives data regarding the vibration, determines whether the vibration exceeds a pre-determined limit, and if so, takes action to reduce the vibration of the electric motor below the pre-determined limit. Such action may involve slowing or stopping the motor, thereby avoiding damage, increasing reliability, and reducing cost.
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Citations
20 Claims
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1. An electric motor system for limiting a vibration of an electric motor, the electric motor system comprising:
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the electric motor, including a shaft configured to drive a load; a motor control subsystem configured to control operation of the electric motor, including running the electric motor in accordance with a command specifying a speed or torque at which the electric motor is to be run; a vibration sensor configured to sense a characteristic of a vibration of the electric motor; an electronic control element configured to receive data from the vibration sensor regarding the characteristic of the sensed vibration, determine whether the characteristic of the sensed vibration exceeds a pre-determined limit, and if so, reduce the speed of the electric motor to reduce the vibration of the electric motor below the pre-determined limit; and an electronic memory element configured to store the pre-determined limit used by the electronic control element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electric motor system for limiting a vibration of an electric motor, the electric motor system comprising:
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the electric motor, including a shaft configured to drive a load; a motor control subsystem configured to control operation of the electric motor, including running the electric motor in accordance with a command specifying a speed or torque at which the electric motor is to be run; a software component configured to determine a characteristic of a vibration of the electric motor; an electronic control element configured to receive data from the software component regarding the characteristic of the vibration, determine whether the characteristic of the vibration exceeds a pre-determined limit, and if so, reduce the speed of the electric motor to reduce the vibration of the electric motor below the pre-determined limit; and an electronic memory element configured to store the pre-determined limit used by the electronic control element. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for limiting a vibration of an electric motor, wherein the electric motor is a variable speed, three-phase, multi-pole alternating current motor, wherein the electric motor includes a shaft configured to drive a load, and wherein the load is selected form the group consisting of:
- a fan, a pump, a blower, a rotating drum, a component of a clothes washer or clothes dryer, a component of an oven, a component of a heating and air-conditioning unit, and a component of a residential or commercial machine, the method comprising the steps of;
controlling the electric motor with an electronic control element in accordance with a command specifying a speed or torque at which the electric motor is to be run; determining a characteristic of a vibration of the electric motor; determining whether the characteristic of the vibration exceeds a pre-determined limit st2ored in an electronic memory; and if the characteristic of the vibration exceeds the pre-determined limit, reducing by the electronic control element the speed of the electric motor to reduce the vibration of the electric motor below the pre-determined limit. - View Dependent Claims (16, 17, 18, 19, 20)
- a fan, a pump, a blower, a rotating drum, a component of a clothes washer or clothes dryer, a component of an oven, a component of a heating and air-conditioning unit, and a component of a residential or commercial machine, the method comprising the steps of;
Specification