Infrared Sensor and Method for Electrical Monitoring

• US 20120170612A1
• Filed: 12/29/2011
• Published: 07/05/2012
• Est. Priority Date: 12/30/2010
• Status: Active Grant

• Current Assignee: Exergen Corporation
• Original Assignee: Exergen Corporation
• Inventors: Pompei, Francesco
• Granted Patent: US 9,170,158 B2
• Time in Patent Office: Days
• US Class Current: 374/126
• CPC Class Codes: G01J 5/00 Radiation pyrometry, e.g. infrared or optical thermometry
• CPC Class Codes: G01J 5/0066 for hot spots detection
• CPC Class Codes: G01J 5/0096 for measuring wires, electrical contacts or electronic systems
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/07 Arrangements for adjusting the solid angle of collected radiation, e.g. adjusting or orienting field of view, tracking position or encoding angular position optical collimating elements G01J5/0806
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52
• CPC Class Codes: G01K 7/02 using thermoelectric elements, e.g. thermocouples

Abstract

An inexpensive thermopile temperature detector is particularly adapted to monitoring of electrical equipment, such as a power bus bar, within an enclosed area such as a cabinet. The detector may have a plastic housing, a thermopile sensor and a plastic Fresnel lens. Each sensor also includes a calibrated element such that, but for calibration, the same sensor may be used for various applications for different target sizes and distance or, more generally, with respect to effective target percentage of field of view.

Claims

1. A method of monitoring electrical equipment comprising:

providing a sensor comprising a thermopile and a calibrating element;

positioning the sensor to view a target element of the electrical equipment, the sensor being at about ambient temperature of the target element of the electrical equipment; and

detecting a voltage output of the sensor, calibrated with respect to target element size and target distance, to provide an indication of temperature differential between the target element of the electrical equipment and the sensor.

2. The method as recited in claim 1 wherein the sensor is calibrated with respect to ratio of target distance and target width.

3. The method as recited in claim 1 wherein the target element is a bus bar.

4. The method as recited in claim 1 wherein the voltage output is calibrated by selecting from one of plural sensor models, the models calibrated with respect to different target element sizes and target distances.

5. The method as recited in claim 1 wherein the voltage output is calibrated by output electronics.

6. The method as recited in claim 1 wherein the output is a silicon based thermopile.

7. The method as recited in claim 1 wherein the sensor comprises a plastic housing and Fresnel lens and has copper leads therefrom, and voltage output is detected without regard to temperature of the sensor.

8. A method of monitoring electrical equipment comprising:

providing a sensor comprising a thermopile and a calibrating element;

positioning the sensor to view a target element of the electrical equipment, the sensor being at about ambient temperature of the target element of the electrical equipment; and

detecting a voltage output of the sensor, calibrated with respect to effective target percentage of field of view, to provide an indication of temperature differential between the target element of the electrical equipment and the sensor.

9. The method as recited in claim 8 wherein the sensor is calibrated with respect to ratio of target distance and target width.

10. The method as recited in claim 8 wherein the target element is a bus bar.

11. The method as recited in claim 8 wherein the voltage output is calibrated by selecting from one of plural sensor models, the models calibrated with respect to different target element sizes and target distances.

12. The method as recited in claim 8 wherein the voltage output is calibrated by output electronics.

13. The method as recited in claim 8 wherein the thermopile is a silicon based thermopile.

14. The method as recited in claim 8 wherein the sensor comprises a plastic housing and Fresnel lens and has copper leads therefrom, and voltage output is detected without regard to temperature of the sensor.

15. A temperature sensor comprising:

a thermopile;

a calibrating resistor adjusted to calibrate the sensor with respect to target size and target distance; and

an identifier enabling selection of the calibrated sensor based on target area and target distance.

16. The sensor as recited in claim 15 wherein the sensor is calibrated with respect to ratio of target distance and target width.

17. The sensor as recited in claim 15 wherein the thermopile is a silicon based thermopile.

18. The sensor as recited in claim 15 wherein the sensor comprises a plastic housing and Fresnel lens and has copper leads therefrom.