GB490635A - A testing apparatus for comparing high tension currents - Google Patents

Abstract

490,635. Detecting faults; testing ignition. CUNNELL. R. J. Oct. 16, 1937, No. 28183. [Class 37] [Also in Group XXVII] A testing device, particularly for the ignition system of an automobile internal - combustion engine, comprises a multispark gap assembly consisting of at least three electrodes 1, 2, 3 of which the electrode 3 is common and adjustable in a support 4 to form two or more mutually adjustable spark gaps 5, 6. This assembly is combined with a two-pole-two-way switch 14, which, when thrown to the left, Fig. 2, connects the primary of a standard induction coil 13 in series with an ammeter 17 and an interrupter 11 driven by a motor 12, across the low tension supply, for example, from the automobile, at terminals 18, 19, whereby the high tension winding of coil 13 produces a spark across the gap 5. By throwing switch 14 to the right, the low tension winding of the ignition or other coil under test connected across terminals 20, 21, is connected in series with the contact breaker 11 and ammeter 17 across the supply 18, 19. The high tension side of the coil under test is connected to terminal 25 and a spark produced across the gap 6 by this coil may readily be compared with the spark across gap 5 caused by the standard coil 13 by moving switch 14 from one position to the other. The speed of the contact breaker may be varied by altering the motor speed through a rheostat 28 and regulator 29 which may be short circuited at 30. A regulating resistance 31 in the primary circuit of coil 13 may also be cut out by a switch 32. Condenser tests are made by connecting the condenser to be tested between terminals 22, 23 and throwing a two-way switch 16 firstly to the right-hand position and then to the left, thereby connecting a master condenser 15 and then the condenser under test successively across the interrupter contacts 11. The switch 14 being in the left-hand position, sparks are produced across the gap 5 by the coil 13 and the alteration in the sparks as the switch 16 is operated gives an indication of the state of the test condenser. The amount of sparking at the interrupter contacts 11 gives an additional indication as to the condition of the test condenser. Insulation tests are effected by test prods connected to terminals 18, 24, with the switch 14 in the left-hand position, defective insulation being indicated by sparks passing between one of the prods and the article under test when the other prod is connected to the metallic parts of the test article. The behaviour of the ammeter 17 gives an additional comparison when testing ignition coils and is provided with terminals 39 for connecting it to the contact breaker of the ignition system under test for comparing the latter with the interrupter 11. The apparatus is mounted on base panels 7, 8, in a box 9 provided with a hinged lid 10, and a volt meter 40 is provided for voltage tests. Three or more spark gaps and further master induction coils may be provided with addition switching means to accommodate test coils requiring different voltages.