APPARATUS FOR LOCATING A SHORT CIRCUIT IN A DC WIRING

• US 3,621,384 A
• Filed: 07/16/1969
• Issued: 11/16/1971
• Est. Priority Date: 07/19/1968
• Status: Expired due to Term

• Current Assignee: Jp,, Minato-Ku Benten
• Original Assignee: Jp,, Minato-Ku Benten
• Inventors: Jp,, Benten, Minato-ku
• Primary Examiner(s): Gerard R. Strecker
• Application Number:
  US04/842,221
• Time in Patent Office: 853 Days
• Field of Search: 324/52,133 340/250,255
• US Class Current: 324/529
• CPC Class Codes: G01R 31/08 Locating faults in cables, transmission lines, or networks
• CPC Class Codes: H02H 3/046 Signalling the blowing of a fuse detecting non functioning of a lamp H05B47/20

Abstract

Apparatus for locating a short circuit in the wiring of a DC circuit having current-intermitting means connected in parallel with a power supply fuse of the circuit for intermittently conducting a current from a power source of the circuit to the wiring when the fuse is blown. A searching unit includes a search coil for detecting an alternating field formed around a portion of the wiring through which the intermitting current flows. The current-intermitting means includes a voltage detector for generating output signals when the voltage applied to the opposite terminals of the current-intermitting means due to blowing of the fuse reaches such a high voltage as applied if any point of the wiring is short circuited. The current-intermitting means also includes means for supplying periodic pulses into the wiring by intermittently connecting the power source to the wiring when the means for supplying periodic pulses receives actuate signals from the preselected voltage detector.

Claims

1. Apparatus for locating a short circuit in a wiring of a DC circuit which comprises, in combination:

current-intermitting means connected in parallel with a power supply fuse of said circuit for intermittently conducting a current from a power source of said circuit to said wiring when said fuse is blown;

a searching unit having a search coil for detecting an alternating field formed around a portion of said wiring through which the intermitting current flows; and

said current-intermitting means including a voltage detector for generating output signals when the voltage applied to the opposite terminals of said current intermitting means due to blowing of said fuse reaches a predetermined high voltage as a result of any point of said wiring being short circuited, and means for supplying periodic pulses into said wiring by intermittently connecting said power source to said wiring when said means for supplying periodic pulses receives the output signals from said voltage detector.

2. Apparatus for locating a short circuit in a wiring of a DC circuit as defined in claim 1, in which said current-intermitting means further includes unidirectional conductive means for actuating said current-intermitting means only when the parallel connection of said current-intermitting means with said fuse is held at a predetermined correct polarity for the normal operation of all the elements constituting said current-intermitting means.

3. Apparatus for locating a short circuit in a wiring of a DC circuit as defined in claim 1, in which said current-intermitting means further includes a constant voltage circuit having an output terminal connected to said voltage detector for providing the normal operation of said voltage detector and said pulse supply means irrespective of the value of said power supply voltage.