Patent GB-158673-A (GB)
Title: An improved electrical testing apparatus
IPC: F02P17/00
Filed: 1919-11-07
Abstract: 158,673. Scorey, A. T., and Brella Manufacturing Co., Ltd. Nov. 7, 1919. Combinations of instruments; current detectors; locating faults; resistances, measuring; magnetic tests. -A portable apparatus for use in testing electric installations on motor-cars, particularly such parts as sparking-plugs, high pressure wiring, magneto armatures, slip-rings, collectorbrush holders, distributors, insulators, and magnets, comprises an induction coil, trembler interrupter, and switches mounted with in a box, the top of which forms a support for an adjustable safety spark-gap and flexible test conductor in the high-pressure circuit, a cradle or bed for the reception of magneto armature under test, an adjustable spark-gap operating in connection with the cradle &c., and terminals for supply conductors. A magnetometer may be added. As shown, the non-conducting cover c, Fig. 1, supports the two adjustable spark-gaps d, d<1>, f, f<1> and a metal plate e having a shallow groove e<1> to receive a sparking-plug or magneto armature to be tested. Adjustably clamped by a cone nut f<4> in a split terminal f<1> of one spark-gap is a connector f<2> in the form of an inverted U, the free limb of which is formed by a flexible spring or chain. A high-pressure flexible conductor g attached to a terminal g' is fitted with an insulated handle g<2> normally held by a clip g<4> and carrying. a point contact g<3>. In testing a sparking-plug, it is placed on the plate e, and the point contact g' is applied to the plug terminal. Simultaneously two press-button switches l, m, Figs. 1 and 3, are closed so as to complete the battery circuit through terminals i, i<1>, and the primary winding q and trembler p of the coil. One terminal of the secondary is permanently connected to the make-andbreak screw, and to one spark-gap terminal d<1>, and the other secondary terminal to the spark-gap terminal d and point contact g<3>. If the sparking- plug is faulty, sparks pass at the gap d, d<1> and not at the plug. To test a high-tension conductor on a motor-car, the ends of the conductor are disconnected and the plate e is connected to the engine or chassis. The point contact g<3> is then applied to one end of the conductor and the switches l, m clcsed, thus connecting the plate e to the common terminal of the primary'and secondary windings as well as closing the primary circuit. Faulty insulation is shown by failure to spark at the gap d, d<1> and by sparking at the fault. A magneto armature may be placed on the plate e with the iron in the groove e<1>, the contact breaker of the armature being removed, and the screw replaced so as to make contact with a spring blade d<2> attached to one terminal of the spark-gap d, d<1>. The connector f<2> is adjusted so that the spring bears on the slip ring of the armature. By depressing a switch button k and tapping a key j which bears on the trembler, an intermittent current is sent through the armature, and sparking occurs at the gap f, f<1> unless there is a fault in the armature &c., in which case the slip ring may be removed and the test repeated. The contact screw n of the trembler is accessible through the cover c. The magnetometer consists of two aluminium blocks h, h<1> mounted on the cover c and slotted to receive the ends of an iron rod h<2> resting on the cover. Steps cut in the blocks to receive magneto magnets of various sizes are of such heights that the magnets, if of the proper strengths, pick up the armature bar h<2>.