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No. 2, followed by a spark in cylinder No. 4 and lastly one in cylinder No. 3.

Q. Describe action of distributor system.

A. It is not necessary to use a separate unit for each cylinder to be fired as single induction coil may be used for any number of cylinders, if a combined primary timer and secondary distributor is employed. A distributor system for a six cylinder engine is clearly shown at Fig. 104. The batteries are connected to the switch which is mounted on the face of the spark coil in the customary manner and the connection between the switch lever and the primary winding is made in the regular way, only that the wire does not show because the connect on is made inside of the coil box. The primary timer is just the same as the form used in all battery ignition systems except that the six insulated primary contact segments are joined together by a metal band outside of the body and a single wire leads from these to the primary terminal at the top of the coil, which is exactly the same type as used on a single cylinder engine.

The secondary terminal of the coil is connected to the rotating distributing brush carried at the upper portion of the distributor. This secondary brush establishes contact with the various terminals, which are joined to the spark plugs in the cylinders. The wires are arranged in such a manner that the spark plugs are brought into action progressively as the firing order dictates. The primary timer portion establishes six contacts every revolution and all of these energize the one primary winding. The distributor brush is depended on to do the timing and to convey the high tension current from the spark coil to the plug where the spark is to occur.

Q. What are the advantages of the distributor system?

A. When a separate induction coil unit is used for each cylinder it is difficult to adjust the vibrators on all of the coil units so that they will be exactly the same in adjustment and it is possible for one or more of the vibrators to lag behind the others, i. e. they will not start to vibrate as quickly as those which may differ in adjustment and as a result the spark does not occur at absolutely the same time relative to the piston position in all the cylinders. When a single coil is used on a multiple cylinder engine but one vibrator

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Fig. 104.-Typical High Tension Battery Ignition System With Secondary Distributor for Six-Cylinder

Engine.

is provided and its adjustment is the same for all cylinders. As the one vibrator is depended on it will be kept in constant motion and less primary current will be needed to energize the primary windings.

A properly installed secondary distributor is the simplest method of obtaining synchronized ignition with battery and coil system. The use of a single coil greatly simplifies the system, especially on four and six cylinder engines where the multiple unit coil is large and occupies considerable room. The electrical wiring is simplified and the liability of trouble owing to short circuited wires, loose connections, etc., reduced because less w re is needed

Q. What is the "master vibrator system"?

A. A master vibrator system is similar to the conventional multiple unit coil ignition method, the only exception being that a specially constructed vibrator is used for all four units of the coil. It is wired in circuit with the various coil units and operates regardless of which contact is made at the primary timer. With a master vibrator the advantage offered by the distributor system of only having one vibrator for any number of cylinders is obtained, but the wiring is not simplified and practically all the parts used in the conventional multiple unit coil system are used with the addition of the master vibrator. A master vibrator coil will consume more current than the regular multiple vibrator coil or a single coil used with a distributor.

Q. Describe simple true high tension magneto system.

A. The essential parts of a high tension magneto ignition system are outlined in diagram form at Fig. 95-A and it will be seen that the wiring is very simple and not liable to give trouble. In this diagram the armature is shown in part section so that the various components and the methods of connecting them together can be readily ascertained. When the device is actually in use there are but five external wires. Four of those are heavily insulated and extend from the terminals on the magneto distributor to the spark plugs in the cylinder. The remaining wire is joined to the ground and can be interrupted when desired by a switch. Unlike a battery ignition system, the ground wire circuit is completed when it is

desired to interrupt the magneto action and the switch is opened when the magneto is to supply current.

The internal wiring is not difficult to follow. One end of the primary winding is attached to the condenser case while the other is joined to the ground. The same wire that joins the condenser to the primary coil is attached to one of the leads of the secondary winding. The other end of the secondary winding goes to the col

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Fig. 105.-Explaining Wiring of Splitdorf Transformer Coil Magneto

System.

lector ring carried by the insulating spool on the magneto armature shaft and from thence the current is collected by a carbon brush and delivered to the revolving portion of the secondary distributor. The primary wire attached to the condenser case extends through and is in electrical connection with the insulated contact point in the contact breaker. The other contact lever is

grounded. The condenser casing is made in two parts, one of these being in metallic contact with the ground while the other which is insulated from it serves to convey the primary current to the breaker box.

As the armature revolves, the contact breaker points separate when the bell crank is rocked by the actuating cam rolls and each time that this break occurs, this being timed so that it is simultaneous with the position of maximum current generation of the armature, a spark takes place at whichever spark plug the distributor arm (which is also timed in relation to armature travel) happens to deliver the current to. As will be evident the true high tension magneto system is very simple when compared to battery and coil ignition systems that do not give as hot a spark and that are not nearly as reliable.

Q. Outline transformer coil magneto system.

A. The wiring arrangement of a transformer coil ignition system using magneto current is clearly shown at Fig. 105, the various parts being separated in order to make the action clear. As is true of the simpler high tension system the spark plugs are connected to terminals on a distributor and the high tension current is delivered to the central revolving member of the magneto distributor. Instead of the derived current being taken directly from the magneto armature it is passed through the primary winding of an induction coil which is similar in action and construction to the form used with batteries except that it has no vibrator. One end of the primary winding is grounded while the other goes to the magneto terminal of the switch and from thence through the magneto armature from which it flows back again to the ground through the medium o the magneto contact breaker.

When the armature is in the position of maximum current generation, the platinum points of the contact breaker are separated by the cam and the primary current must rush through the primary winding of the coil before it reaches the ground instead of having a short circuit to the ground through the contact points of the contact breaker, as is possible when these are together. The rush of current through the primary winding induces a secondary current

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