Circuit continuity detection system and method

Details Circuit continuity detection system and method Circuit continuity detection system and method

1999-04-19

2001-02-20

Lieu, Julie (Department: 2736)

Communications: electrical

Condition responsive indicating system

Specific condition

C340S635000, C340S640000, C340S664000

Reexamination Certificate

active

06191697

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a circuit continuity detection system and method, and more specifically, to a circuit continuity detection system and method that senses current and voltage simultaneously at a single point of operation.
2. Description of the Related Art
In many technical applications, situations often arise where it is desirable to know, in real time, if a circuit is functioning. That is, it is desirable to know if, for example, a heater element is operational or “blown” (open). It is relatively simple to determine if the circuit is operational by sensing the current flowing to the circuit.
However, this only provides information while the circuit is in the process of operating. There must be some real-time relation to or connection with the request or demand for power, to determine if the device is in fact not operational, or if there is simply no controller request to provide power. Conventional devices provide no such means to arbitrate the presence of current in a circuit along with the voltage request or demand for power.
Furthermore, indication of a failure condition would require a continual or known interval monitor, or a connection to a controller device for continual monitoring and condition reporting. Even then, some connection with the request for power must be made to enable the proper function to be determined.
Conventional, discrete current sensing loops and voltage sensing coils could be used to derive the required parameters, and with the application of an external arbitration means, one could derive the function described. However, this method is costly, cumbersome and requires externally-powered devices. Further, its distributed nature makes it a formidable challenge to implement.
Therefore, it is necessary to assess and arbitrate the current and voltage demand at a single point to provide ease of integration. The most obvious point to obtain these parameters is at the circuit breaker that governs the operation of the circuit.
FIG. 1A
illustrates a conventional circuit breaker
10
for detecting a current overload condition. Circuit power is provided from an external source
15
, connected to a contact
19
. The breaker includes an ON-OFF activation switch
13
which enables or disables the device's function, a current sensing coil
11
, which is attached to a set of normally closed contacts
14
a,
14
b,
and a pivot
12
that allows the actuation of contact
14
a
into an open state (e.g. away from its mating “closed” contact
14
b
) upon sensing a current overload condition. This operation “breaks” (e.g., opens) the circuit and protects the load from damage from exposure to a current above the breaker rating.
FIG. 1B
illustrates a standard implementation of the circuit breaker of
FIG. 1A. A
voltage source
15
is connected to a voltage controller
16
, which sends power to the circuit. The power is routed to one or more loads through separate circuit breakers (e.g., CB1—
10
a
, CB2—
10
b
). The load
18
a,
18
b
is connected in series to its respective circuit breaker
10
a,
10
b.
The device of
FIG. 1A
, as implemented in
FIG. 1B
, provides the ability to open or “trip” within the series circuit to which it is installed. It has no ability to arbitrate request or demand for circuit activation, and it provides no means for external communication about its state or condition, nor about the state or condition of the circuit in which it is installed, nor about the state or condition of the load attached (e.g.,
18
a
,
18
b
).
SUMMARY OF THE INVENTION
In view of the foregoing problems of the conventional circuit breaker, an object of the present invention is to provide a structure and method for determining the state of the load of a circuit (e.g., for determining whether the load of a circuit is functional or nonfunctional (open load).
In a first aspect of the present invention, a circuit continuity detection system coupled to a voltage source and load includes a current sensor for sensing current through a circuit, a voltage sensor for sensing the presence of voltage from the source to be delivered across the load, and an arbitration device (and method) to simultaneously arbitrate signals from the current sensor and the voltage sensor to determine an operable status of the load.
In a second aspect of the present invention, a circuit breaker coupled between a voltage source and a load includes the above described circuit continuity detection system.
In a third aspect of the present invention, a method of detecting continuity of a circuit coupled to a voltage source and a load, includes sensing a current drawn through a circuit to produce a first output, sensing a voltage applied from the source across the load, simultaneously with sensing of the current, to produce a second output, and arbitrating the first and second outputs to determine an operable status of the load.
With the unique and unobvious features of the present invention, an open load condition can be detected via the detection of simultaneous applied voltage and the absence of circuit current.
Further, the structure of the invention can be implemented as a discrete device in a host of applications and need not be implemented as part of a circuit breaker.
With the invention, and taking the circuit breaker as an exemplary application, the load is connected to the breaker, and the detector can determine the load circuit's operational status. In the case of a circuit connected as a load to the device, when an open load condition exists, the device detects and reacts to the open load condition. The invention can detect a resistive load circuit's failure (open load condition) in real time, and can utilize a majority of existing hardware to minimize implementation costs and effort.
Furthermore, existing industrial applications can be upgraded to the device described by the invention within the same physical space (“footprint”), and without mechanical modifications. Thus, existing systems can be easily retrofitted with the inventive system.


REFERENCES:
patent: 3716834 (1973-02-01), Adams
patent: 4168491 (1979-09-01), Phillips et al.
patent: 4323914 (1982-04-01), Berndlmaier et al.
patent: 4333119 (1982-06-01), Schoenmeyr
patent: 4412267 (1983-10-01), Hansen
patent: 4421976 (1983-12-01), Jurek
patent: 4558310 (1985-12-01), McAllise
patent: 4833564 (1989-05-01), Pardue et al.
patent: 5245289 (1993-09-01), Rumfield et al.
patent: 5424894 (1995-06-01), Briscall et al.
patent: 5488303 (1996-01-01), Bagalini
patent: 5548523 (1996-08-01), Wehrli, III et al.
patent: 5600524 (1997-02-01), Neiger et al.
patent: 5684443 (1997-11-01), Runyan et al.
patent: 5705989 (1998-01-01), Cota et al.
patent: 5715125 (1998-02-01), Neiger et al.
patent: 5959537 (1999-09-01), Banting et al.

Affiliated with

Also associated with

Rating

Circuit continuity detection system and method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Circuit continuity detection system and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit continuity detection system and method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2574529