Capacitance measurement device

• US 7,619,420 B2
• Filed: 01/09/2007
• Issued: 11/17/2009
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: AmRad Manufacturing, LLC
• Original Assignee: American Radionic Company Incorporated
• Inventors: Stockman, Robert M.
• Primary Examiner(s): Dole; Timothy J
• Assistant Examiner(s): Baldridge; Benjamin M
• Application Number:
  US11/621,428
• Publication Number:
  US 20080042641A1
• Time in Patent Office: 1,043 Days
• Field of Search: 324/663
• US Class Current: 324/663
• CPC Class Codes: G01R 15/12 Circuits for multi-testers , i.e. multimeters, e.g. for measuring voltage, current, or impedance at will
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines

Abstract

An apparatus includes a measurement device for measuring two capacitances. The apparatus also includes a display module that simultaneously displays at least two numerical values based on the measured capacitances.

Claims

1. An apparatus comprising:

a single measurement device for simultaneously measuring a first capacitance and a second capacitance;

a display module for simultaneously displaying at least a first numerical value based on the first measured capacitance and a second numerical value based on the second measured capacitance,

wherein the first measured capacitance is provided by a first portion of a motor run capacitor, the second measured capacitance is provided by a second portion of the motor run capacitor, and the first measured capacitance and the second measured capacitance are different;

a selector for establishing a first range of measurable capacitances for the first measured capacitance and establishing a second range of measurable capacitances for the second measured capacitance;

the selector being further operable to select a first precision for the first numerical value and a second precision for the second numerical value;

a common port used in measuring the first measured capacitance and the second measured capacitance;

a common lead connected to the common port and configured to attach to a common connector of the motor run capacitor;

a first port used in measuring the first measured capacitance;

a first lead connected to the first port and configured to attach to the first portion of the motor run capacitor;

a second port used in measuring the second measured capacitance;

a second lead connected to the second port and configured to attach to a second portion of the motor run capacitor; and

a safety circuit connected to the common port, wherein the safety circuit includes a fuse.

2. The apparatus of claim 1, wherein the display module comprises at least two displays.

3. The apparatus of claim 2, wherein a first of the at least two displays is configured to present a numerical value representative of the first capacitance.

4. The apparatus of claim 3, wherein a second of the at least two displays is configured to present a numerical value representative of the second capacitance.

5. The apparatus of claim 1, wherein the display module comprises a liquid crystal display.

6. The apparatus of claim 1, wherein the display module comprises a light emitting diode.

7. The apparatus of claim 1, further comprising:

a display driver for processing the first measured capacitance and driving the display module to display one of the numerical values.

8. The apparatus of claim 7, wherein the processing comprises assigning a unit of measure to the first measured capacitance.

9. The apparatus of claim 1, further comprising:

a selector for controlling the measurement device and display module.

10. The apparatus of claim 9, wherein the selector controls a capacitance range.

11. The apparatus of claim 9, wherein the selector controls display precision.

12. An apparatus comprising:

a single measurement device comprising;

a first measurement module for measuring a first capacitance provided by a first portion of a motor run capacitor and

a second measurement module for measuring a second capacitance provided by a second portion of the motor run capacitor, the second capacitance different from the first capacitance, wherein the first capacitance and the second capacitance are respectively measured in a substantially simultaneous manner by the first measurement module and the second measurement module;

a first display module for displaying a first numerical value representative of the first measured capacitance;

a second display module for displaying a second numerical value representative of the second measured capacitance, wherein the first and second numerical values are simultaneously displayed;

a first display driver for driving the first display module to display the first numerical value;

a second display driver for driving the second display module to display the second numerical value;

a selector for providing data to the first and second display drivers and for establishing a range of measurable capacitances for the first measurement module and the second measurement module;

a first port and a second port, the first port connected to a first lead for connecting the first measurement module to the first portion of the motor run capacitor and the second port connected to a second lead for connecting the second measurement device to the second portion of the motor run capacitor;

at least one common port connected to a common lead for connecting to a common connector of the motor run capacitor and used in measuring the first capacitance and the second capacitance; and

a safety circuit connected to the at least one common port, wherein the safety circuit includes a fuse.

13. The apparatus of claim 12, wherein the at least two ports comprise:

a first port connected to the first measurement module;

a second port connected to the second measurement module; and

a common port connected to the first and second measurement modules.

14. The apparatus of claim 12, wherein the selector further controls the capacitance range of the first measurement module.

15. The apparatus of claim 12, wherein the selector controls the displayed precision of the first and second numerical values.

16. A method comprising:

connecting a first lead to at least a portion of a motor run capacitor, the first lead connected to a first port of a single measurement device;

connecting a second lead to a second portion of the motor run capacitor, the second lead connected to a second port of the single measurement device;

connecting a common lead to a common connector of a motor run capacitor, the common lead connected to a common port of the single measuring device;

wherein the common port is connected to a safety circuit, the safety circuit including a fuse;

simultaneously displaying a first numerical value and a second numerical value on a single unit that includes a measurement device for measuring capacitance and a display module, wherein the numerical values respectively represent a first capacitance measured from first portion of the motor run capacitor and a second capacitance measured from the second portion of the motor run capacitor, different from the first capacitance, measured in a substantially simultaneous manner by the single unit; and

establishing a selected range of measurable capacitances for the first capacitance and the second capacitance,

wherein the measurement device contains at least one common port used in measuring the first capacitance and the second capacitance.

17. The method of claim 16, further comprising:

selecting the precision of at least one of the numerical values.

18. The method of claim 16, further comprising:

selecting the capacitance range of the device.

19. The method of claim 16, wherein the first capacitance is provided by a first capacitive element under measurement and the second capacitance is provided by a second capacitor element under measurement.