GB753392A - Test apparatus for electrical systems - Google Patents

Abstract

753,392. Testing motor vehicle electrical systems. SPERRY CORPORATION. May 10, 1954 [May 11,1953], No. 13543/54. Class 37. Relates to apparatus for testing that portion of a motor vehicle electrical system comprising the battery 21, Fig. 1, the starter motor 24, the generator 10 and the regulator 16. The latter comprises in one unit the cut-out 35 connected between generator 10 and battery 21 and the voltage and current regulators 36, 37 and co-operating generator field-reducing resistance 38. The invention provides a testing apparatus 62, Fig. 4, having leads 30-33 emerging therefrom which are clipped (see Fig. 3) to the -regulator terminals: 17 (armature); 18 (field); 19 (battery); 20 (ground) and need not be disturbed throughout the tests. The apparatus 62 has instruments, switchgear, &c., and circuits made via leads 30- 33 for checking battery and generator voltage and current and (i) by-passing the cutout 35, (ii) by-passing the voltage and current regulators 36, 37 for an externally grounded field (light duty) generator, Fig. 1, or an internally grounded field (heavy duty) generator, Fig. 2, (iii) selecting testing components appropriate for tests on batteries of different voltage rating, e.g. 6, 12 or 24 volts. The dials of the voltmeter 41 and ammeter 42 may be inscribed or coloured to indicate test limit readings. Preliminary of test preparation procedure.-The four clip leads 30-33 are applied to terminals 17-20 of regulator 16 as shown, Fig. 3. Next according to whether the system is 6, 12 or 24 volt working the system selector switch 51, Fig. 4, is positioned to the right, left or centre to select suitable values of(i) voltmeter multiple resistances 48, 49 and 50; (ii) battery load resistances 52 to 54; (iii) artificial load resistances (replacing normal battery load on generator test) 52 to 57. The operator may then close the generator selection switch 59 to right or left according to whether the test generator is a heavy or light duty type and thus prepare for regulator by-pass switch 60 to be grounded or connected to the armature. Actual test procedure for 6-volt system.-The field flash switch 45 is momentarily closed so that battery 21 flashes the armature circuit of generator 10 to check for short-circuits or high resistance in the armature circuit and polarize the polepieces of the field windings. The voltmeter switch 46 is now closed to battery and the load switch 58 is closed in the left hand position and voltmeter 41 reads the voltage drop across calibrated resistance 52 and tests the battery circuit resistance. The battery-starter circuit is also checked by reading the voltmeter 41 with the engine cranked and ignition turned off. The voltmeter switch 46 is now changed to the generator position and the running generator is loaded with lights, heater, &c. and with the regulator by-pass switch 60 closed momentarily ammeter 42 indicates generator overload output. The engine is now idled and the speed gradually increased so that the generator output voltage at which the cut-out 35 closes is read on the voltmeter 41. Next with the generator running the voltage and current at which the regulators 36, 37 operate is read on voltmeter and ammeter 41, 42 and for these tests the battery lead 27 is removed from ammeter shunt 29, Fig. 3, and the generator is loaded by changing the load switch 58 to its right hand position to introduce load resistances 52, 55. A high current shunt 39, Fig. 3, may be added to the test apparatus (i.e. plugged into jack 44 belonging to ammeter 42) to check the current drawn by the starter motor 24 when the engine is being cranked. Also, if desired, voltage drop tests on any component may interrupt normal test procedure and for this purpose voltmeter 41 has a shorting jack 61 so that insertion of plugs from voltagedrop check leads disconnects the voltmeter 41 from other inputs.