GB1295632A - - Google Patents

Abstract

1295632 Detecting hidden masses ELECTRICITY COUNCIL 21 Nov 1969 [21 Aug 1968] 39949/68 Heading G1N [Also in Division H1] Apparatus to detect the position of a ferromagnetic wire embedded in a cable, see Division H1, consists of a magnet 80, Fig. 10 pivoted about an axis parallel to it, fitted with a flywheel 81 so that the magnet does not respond to the A. C. field produced by the cable, and able to touch contacts 88, 87. In the absence of the ferromagnetic wire the magnet is biased by a light spring (93) Fig. 13 (not shown) against contact 87. As the apparatus is rotated about the cable, attraction between the wire and magnet causes contact 87 to open and, while the magnet is balanced between the contacts, the indicator bulb 121 lights, showing that the wire is directly beneath the magnet. The circuit is disclosed in Fig. 15 (not shown). In a second embodiment, Fig. 3; Figs. 4-6 (not shown) two longitudinally spaced magnets 22 are angularly displaced about the cable circumference, Fig. 6b (not shown) and biased such that only when each is attracted to the ferromagnetic wire when the latter is directly beneath the apparatus will a circuit through the magnets be completed and a lamp energized, Fig. 8 (not shown). The apparatus may be fixed at any one of three positions with respect to a jig, so that, when a given one of the three indicator lamps is energized, the jig is set up for working on a corresponding one of three phase conductors in the cable.