Machine monitor with tethered sensors

• US 6,138,078 A
• Filed: 06/25/1998
• Issued: 10/24/2000
• Est. Priority Date: 08/22/1996
• Status: Expired due to Term

• Current Assignee: Computational Systems Incorporated (Emerson Electric Company)
• Original Assignee: CSI Technology Incorporated (Emerson Electric Company)
• Inventors: Robinson, James C., Canada, Ronald G., Pardue, Eugene F.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Bui, Bryan
• Application Number:
  US09/104,688
• Time in Patent Office: 852 Days
• Field of Search: 702/32-33, 702/44, 702/56, 702/182, 702/189, 318/434, 318/471, 318/490
• US Class Current: 702/44
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: G01R 33/028 Electrodynamic magnetometers
• CPC Class Codes: G07C 3/00 Registering or indicating the condition or the working of machines or other apparatus, other than vehicles
• CPC Class Codes: H02K 11/0094 Structural association with other electrical or electronic devices
• CPC Class Codes: H02K 11/20 for measuring, monitoring, testing, protecting or switching rectifiers H02K11/04; power electronics H02K11/33
• CPC Class Codes: H02K 11/25 Devices for sensing temperature, or actuated thereby
• CPC Class Codes: H02K 11/33 Drive circuits, e.g. power electronics H02K11/38 takes precedence
• CPC Class Codes: H02K 11/35 Devices for recording or transmitting machine parameters, e.g. memory chips or radio transmitters for diagnosis

Abstract

A monitor attaches to a mount proximate a machine to determine the health operating history and operating status of the machine. The monitor is preferably self-contained, having its own internal power source, electronics, and sensor suite. If desired, the monitor may be powered by an external power source. One or more internal sensors disposed in the monitor are provided to sense machine operating parameters such as temperature, flux, and vibration. External sensors tethered to the monitor may be positioned at varying points on and/or in the machine. Monitor electronics process sensor outputs to determine machine operating parameters such as machine speed and load. Monitor electronics are also operable to transform time domain data generated by the sensors to frequency domain data. A communications port enables a peripheral device, such as a notebook computer or a computer network, to communicate with the monitor and download stored data. Downloaded data can be further analyzed and statistically compared with trend data at a base computer to further ascertain the health and condition of the machine.

Claims

1. A monitor that attaches to a mount proximate an electric motor which drives a piece of driven equipment, said monitor for monitoring operation of the motor or the driven equipment, or both, and producing an operation history which includes one or more machine operating parameters, said monitor comprising:

a structural enclosure;

an engagement surface formed on said enclosure;

a fastener for attaching said engagement surface to the mount;

a power supply for supplying electrical power to the monitor;

at least one internal sensor disposed in said structural enclosure for sensing one or more internally sensed operating parameters of the motor and producing internal sensor signals corresponding to the one or more internally sensed operating parameters;

at least one external sensor disposed external to said structural enclosure for sensing one or more externally sensed operating parameters of the motor or the driven equipment, or both, and producing external sensor signals corresponding to the one or more externally sensed operating parameters;

a signal processor disposed in said enclosure for receiving and processing internal and external sensor signals to produce data corresponding to the sensed operating parameters;

memory disposed in said enclosure for storing data corresponding to the sensed operating parameters; and

a communications port for communicating with a peripheral device.

2. The monitor of claim 1 wherein said signal processor is operational to perform a Fourier transform of at least one of said internal and external sensor signals to produce data corresponding to the sensed operating parameters.

3. The monitor of claim 1 wherein said operating parameters are selected from a group consisting of motor speed which is determined by the signal processor, machine load which is determined by the signal processor, cumulative time of machine operation for different categories of loads, and total number of motor starts.

4. The monitor of claim 1 wherein said power supply includes a battery disposed in said structural enclosure.

5. The monitor of claim 1 wherein said power supply comprises a power supply circuit disposed in said enclosure for electrical connection to an external source of power.

6. The monitor of claim 1 wherein said at least one internal sensor is selected from a group consisting of a vibration transducer, a flux sensor, and a temperature sensor.

7. The monitor of claim 1 wherein said at least one external sensor is selected from a group consisting of a vibration transducer, a flux sensor, and a temperature sensor.

8. The monitor of claim 1 wherein said communications port includes a wireless communications port.

9. The monitor of claim 1 wherein said communications port includes a communications module for communicating with a computer network.

10. The monitor of claim 1 wherein at least one external sensor is disposed on said motor.

11. The monitor of claim 1 wherein at least one external sensor is disposed on said driven equipment.

12. The monitor of claim 1 wherein one or more external sensors are disposed on said motor and one or more external sensors are disposed on said driven equipment.

13. A monitor that attaches to a mount on or proximate a piece of driven equipment which is driven by an electric motor, said monitor for monitoring operation of the motor or the driven equipment, or both, and producing an operation history which includes one or more machine operating parameters, said monitor comprising:

a structural enclosure;

an engagement surface formed on said enclosure;

a fastener for attaching said engagement surface to the mount;

a power supply for supplying electrical power to the monitor;

at least one internal sensor disposed in said structural enclosure for sensing one or more internally sensed operating parameters of the driven equipment and producing internal sensor signals corresponding to the one or more internally sensed operating parameters;

at least one external sensor disposed external to said structural enclosure for sensing one or more externally sensed operating parameters of the motor or the driven equipment, or both, and producing external sensor signals corresponding to the one or more externally sensed operating parameters;

a signal processor disposed in said enclosure for receiving and processing internal and external sensor signals to produce data corresponding to the sensed operating parameters;

memory disposed in said enclosure for storing data corresponding to the sensed operating parameters; and

a communications port for communicating with a peripheral device.

14. The monitor of claim 13 wherein said signal processor is operational to perform a fast Fourier transform of at least one of said external and internal sensor signals to produce data corresponding to the sensed operating parameters.

15. The monitor of claim 13 wherein said communications port includes a communications module for communicating with a computer network.

16. The monitor of claim 13 wherein at least one external sensor is disposed on said driven equipment.

17. The monitor of claim 13 wherein at least one external sensor is disposed on said motor.

18. The monitor of claim 13 wherein one or more external sensors are disposed on said driven equipment and one or more external sensors are disposed on said motor.

19. A system for monitoring the condition of one or more machines, the system comprising:

for each of said one or more machines, at least one monitor attached to the machine for sensing and storing at least one operating parameter of the machine, the at least one stored parameter corresponding to the operation history of the machine; and

a computer network connected to each monitor for downloading the stored operation history of each machine.

20. The monitoring system of claim 19 wherein each monitor attaches to a mount proximate a machine and includes:

a structural enclosure;

an engagement surface formed on said enclosure;

a fastener for attaching said engagement surface to the mount;

a power supply for supplying electrical power to the monitor;

at least one internal sensor disposed in said structural enclosure for sensing one or more internally sensed operating parameters of the machine and producing internal sensor signals corresponding to the one or more internally sensed operating parameters;

a signal processor disposed in said enclosure for receiving and processing sensor signals to produce data corresponding to the sensed operating parameters;

memory disposed in said enclosure for storing data corresponding to the sensed operating parameters; and

a communications module for communicating with the computer network.

21. The monitoring system of claim 20, further comprising a communications hub attached to each monitor for controlling communication between each monitor and the computer network.

22. The monitoring system of claim 20, further comprising at least one external sensor disposed external to said structural enclosure for sensing one or more externally sensed operating parameters of the machine and producing external sensor signals corresponding to the one or more externally sensed operating parameters.

23. A method of monitoring one or more machines which generate machine operating parameters, comprising the steps of:

attaching a machine monitor adjacent said one or more machines;

producing sensor signals with said monitor representing a machine operating parameter generated by the machine;

processing the sensor signals with said monitor over time to produce a life history of said operating parameter for the machine;

storing said life history in said monitor; and

transferring the life history of the machine to a computer network connected to the monitor.

24. The method of claim 23 wherein said producing step includes producing sensor signals with a machine sensor disposed in the monitor.

25. The method of claim 23 wherein said producing step includes producing sensor signals with a machine sensor disposed external to said monitor.