Method and apparatus for monitoring electrical devices

• US 5,248,967 A
• Filed: 04/26/1991
• Issued: 09/28/1993
• Est. Priority Date: 04/26/1991
• Status: Expired due to Fees

• Current Assignee: Marek Daneshfar
• Original Assignee: Marek Daneshfar
• Inventors: Daneshfar, Marek
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US07/691,842
• Time in Patent Office: 886 Days
• Field of Search: 340/642, 340/931, 340/458, 340/945, 340/947, 340/953, 340/661, 340/664, 364/483, 307/11, 307/10.8, 315/130, 315/135, 361/110
• US Class Current: 340/931
• CPC Class Codes: G08G 1/097 Supervising of traffic control systems, e.g. by giving an alarm if two crossing streets have green light simultaneously

Abstract

The condition of signal lamps (R1, R2) in a traffic light system is monitored by compiling a table of power consumption levels at different levels of applied voltage. The table is then used to adjust measured levels of power consumption at intervals during the service life of the traffic light system. A fault condition is signalled if the adjusted values differ by more than a predetermined amount.

Claims

1. An apparatus for monitoring power or current consumption of one or more electronic devices, the apparatus comprising:

means for providing a plurality of scalers corresponding to a signature of at least one of a power or current consumption of the one or more electronic devices at various voltage levels during operation;

means for periodically sampling voltage levels applied to said one or more electronic devices at selected time intervals;

means for sampling power or current consumption values representing power or current consumed by said one or more electronic devices at said selected time intervals;

means for adjusting said sampled power or current consumption values with said scalers; and

means for providing an indication when one of said adjusted power or current consumption values varies from another of said adjusted power or current consumption values by more than a predetermined amount.

2. The apparatus as recited in claim 1 wherein said adjusting means adjusts said sample power or current consumption value with said scaler corresponding to the sample voltage level.

3. The apparatus as recited in claim 2 wherein said scalers correspond to a signature of said devices'"'"' power or current consumption at various temperature levels during operation;

and whereas said adjusting means adjusts said sample power or current consumption with said scaler corresponding to the devices'"'"'temperature level during operation.

4. A method for monitoring parameters of one or more electronic devices, the method comprising the steps of:

determining a signature of at least one of said electronic devices, said signature including electrical parameters of said device while in a known operating condition;

storing said signature as values in a memory for recall during subsequent operation of said device;

detecting said electrical parameters of said device at selected time intervals during said device'"'"'s subsequent operation;

adjusting said detected electrical parameters with an input representative of said signature values; and

providing an indication signal when one of said adjusted electrical parameters detected at one of said selected time intervals exceeds another of said adjusted electrical parameters detected at another of said selected time intervals.

5. The method as recited in claim 4 wherein said electrical device is a traffic light system.

6. The method as recited in claim 4 wherein said electrical parameters includes voltage levels of said device.

7. The method as recited in claim 4 wherein said signature includes a temperature adjacent said device during a known operating condition.

8. A method of monitoring the condition of an electrically energizable device, the method comprising the steps of:

energizing the device by application of different levels of voltage in succession;

measuring the power consumption of the device for each different voltage level;

storing a plurality of scalers which have a predetermined relationship with the power consumption of the device at said different levels of voltage;

measuring, at selected times subsequent to storing the scalers, sample voltage levels applied to the device and sample power consumption values applied to the device;

providing adjusted power consumption values for the device by modifying the sample power consumption values of the device with a corresponding one of the scalers;

comparing one adjusted power consumption value with another adjusted power consumption value; and

providing a signal when one adjusted power consumption value of the device varies by a predetermined amount greater than another adjusted power consumption value.

9. The method as recited in claim 8 further comprising the step of providing a adjusted power consumption value by modifying a sample power consumption value of the device with a scaler related to a sample voltage level.

10. The method as recited in claim 8 further comprising the step of providing values representing the power consumption of the device continuously during a period of use of the device, and reading said power consumption values at the selected times.

11. The method as recited in claim 8 wherein the values representing respective applied voltage levels are root mean square values.

12. The method as recited in claim 8 further comprising the steps of providing for each of several other devices, values representing sample power consumption values and applied voltage levels for the other devices;

and using the stored scalers for the device to adjust the sample power consumption values of the other devices.

13. The method as recited in claim 12 comprising the step of changing a voltage level applied to each device cyclically.

14. The method as recited in claim 13 wherein the changes in the voltage level applied to the devices include electrical energization of the devices and de-energization thereof.

15. The method as recited in claim 13 further comprising the step of monitoring the interval between the changes in voltage levels of the device.

16. The method as recited in claim 14 wherein the devices include red, amber and green traffic lights, and further comprises the steps of monitoring the intervals between energizing and deenergizing of the amber light.

17. The method as recited in claim 16 wherein the intervals between energization and de-energization of at least one of the amber traffic lights are compared with pre-selected values.

18. The method as recited in claim 8 further comprising the step of computing each scaler by dividing the power consumption at one level of voltage by the power consumption at another level of voltage.

20. The apparatus as recited in claim 18 wherein respective power measuring means are coupled to the device to be monitored.

19. An apparatus for monitoring the electrical power consumption of a device, the apparatus comprising:

voltage measuring means for detecting a plurality of different voltage levels, each different voltage level representing a voltage applied to the device during known operating conditions;

power measuring means for providing initial power consumption values, each initial power consumption value corresponding to a power consumption at each of the different voltage levels;

a memory for storing a table of scalers, each scaler corresponding to a ratio between the initial power consumption at each of the different voltage levels and the initial power consumption at a selected one of the different voltage levels;

voltage measuring means for detecting a sample voltage corresponding to a voltage level applied to the device at selected time intervals;

power measuring means for detecting a sample power consumption value corresponding to a power consumption of the device at each of the sample voltage levels at the selected time intervals;

a processor including;

(a) means for adjusting said power consumption values with the scaler corresponding to the voltage level applied to the device at the selected time interval;

(b) means for subtracting the magnitude of one of the adjusted power consumption values from the magnitude of another adjusted power consumption value; and

(c) means for providing a signal indicating that one adjusted power consumption value differs from another adjusted power consumption value.