Making a Master Vibrator for Automobiles 



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THE ignition of any motor car 

 equipped with a vibrating coil may 

 be greatly improved by the insertion of 

 a device known as a "master vibrator" 

 in the circuit. It is very difficult to ad- 

 just the separate vibrators for each 

 cylinder, so that sparks of the same in- 

 tensity are produced 

 in each of the 

 cylinders ; but by 

 substituting one vi- 

 brator for the sev- 

 eral originally used, 

 this difficulty is 

 overcome. 



A discarded unit 

 coil may be secured 

 from any garage or 

 second - hand parts 



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The master vibrator 

 as completed 



house, the only requirement being that 

 the vibrator on the end of the coil shall 

 "buzz" when current is passed through 

 the terminals. It is not necessary for 

 this coil to deliver a spark. Hence the 

 condition of tlie secondary winding is 

 unimportant. A single coil which has 

 been removed from a set of two or more, 

 will prove very satisfactory, the box not 

 being required. 



This coil will have three terminals, 

 two for the battery current and one that 

 led to the spark plug. Connect four or 

 five dry cells, as shown, and touch the 

 two wires to any two of the three ter- 

 minals until a pair is found which causes 

 the vibrator to operate. Comiect either 

 one of the two terminals just found to 

 the third (the one that did not cause 

 vibration). This short-circuits the 

 secondary winding of the coil, and makes 

 it inoperative. The two terminals which 

 did cause vibration are to be used. If 

 this coil has no protecting box, it will 

 be best to make one of a size that just 

 takes the coil, with a cover hinged or 

 screwed on over the vibrator end. The 

 two terminals to be used should be 

 brought to the outside of this box, pre- 

 ferably through the .end opposite the 

 cover, and the box containing the coil 

 should then be mounted solidly on the 

 dashboard by the side of the two, four 

 or six-unit coil-box already there. 



It will now be necessary to prepare 



the coils on the car which have been 

 in use for ignition purposes. A per- 

 manent electrical connection must be 

 made between the two platinum points 

 on each vibrator. This may be done 

 in either of two ways. The best meth- 

 od is to run a short piece of copper 

 wire from the metal piece carrying 

 the vibrator-spring to the metal piece 

 on which the other platinum contact 

 is carried. This allows the current 

 that formerly flowed from one contact 

 to the other, to pass through the cop- 

 per wire, and the spring will no longer 

 tremble when current flows. A quicker, 

 although not as satisfactory a method- 

 is to turn the adjusting screw^ on each 

 coil until the two contacts are held 

 tightly together, making the circuit 

 complete at all times and preventing 

 vibration of the spring. 



The wires running from the coil 

 originally used to the timer on the en- 

 gine and to the spark plugs, are to re- 

 main, but all other wires to battery, 

 magneto and switches are to be re- 

 moved from the coil terminals. This 

 completes the preparation of the coil 

 formerly used. 



If the car is equipped with two sets 

 of batteries, or a set of batteries and a 

 magneto (such as the Ford magneto), 



When the contacts are properly adjusted, 



the addition of this master vibrator greatly 



improves the ignition circuit 



it will be necessary to fit a switch hav- 

 ing three terminals, one for the batter- 

 ies, one for the magneto or reserve set 

 of batteries and the other for the coil 

 connection. This switch will have 



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