Circuit arrangement for testing the correct functioning of circuit(s)

• US 4,901,008 A
• Filed: 09/29/1988
• Issued: 02/13/1990
• Est. Priority Date: 10/14/1987
• Status: Expired due to Term

• Current Assignee: Westinghouse Brake and Signal Holdings Limited PEW Hill Chippenha Wiltshire UK
• Original Assignee: Westinghouse Brake and Signal Co Ltd (Siemens AG)
• Inventors: Hill, Nigel K., Quastel, David A.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Nguyen, Vinh P.
• Application Number:
  US07/252,246
• Time in Patent Office: 502 Days
• Field of Search: 324/117 R, 324/117 H, 324/127, 324/251, 324/252, 324/253, 324/234, 324/235, 338/32 H, 364/483, 307/309
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08

Abstract

There is disclosed a circuit arrangement including a load (7) and a current source (1) for supplying current to the load via a current path with a winding (3). A core of magnetizable material (2) is coupled inductively with the winding and a Hall effect transducer (4) detects magnetic flux in the core for use in producing an output indication dependant on the magnitude of the load current. For testing the correct functioning of circuit(s), the circuit arrangement is further provided with an additional winding (6) on the magnetizable core, through which a further current source supply a further current, in which the core is also inductively coupled so that the transducer also detects flux in the core due to the further current.

Claims

1. A circuit arrangement comprising:

(a) a load;

(b) supply means for supplying current to said load via a current path;

(c) a microprocessor connected for controlling the supply of current from said supply means;

(d) means for detecting said current, said detecting means comprising;

(i) a core of magnetizable material;

(ii) a winding coupled inductively with said core, said winding being included in said current path; and

(iii) transducing means for sensing magnetic flux in said core, said transducing means being coupled with said microprocessor for the supply to said microprocessor of an indication being dependent on the magnitude of said current;

the circuit arrangement further including testing means for testing the condition of said detecting means, said testing means comprising;

(e) a further winding coupled inductively with said core; and

(f) further supply means, for supplying current to said further winding, said transducing means also sensing magnetic flux in said core due to current in said further winding when said further supply means supplies such current so that said indication supplied to said microprocessor is then dependent on the condition of said detecting means.

2. A circuit arrangement according to claim 1, wherein the said core forms a closed magnetic circuit with an air gap.

3. A circuit arrangement according to claim 1, wherein the said core is in the shape of a toroid.

4. A circuit arrangement according to claim 2, wherein the said transducing means is located in the said gap.

5. A circuit arrangement according to claim 1, wherein the said transducing means comprises a Hall effect transducer.