Fig. 98.-Defining Construction of Connecticut Magneto. Between Magnets Above Armature Tunnel. A Form in Which the Transformer Coil is Placed The Connecticut magneto, which is a transformer coil type, is shown in longitudinal section and end elevation at Fig. 98. In this, the transformer coil is mounted between the magnets above the armature tunnel and the secondary current is applied directly to the distributing brush by means of a secondary collecting member which bears against a suitable terminal in the bottom of the coil Fig. 99. Showing Application of High Tension Principle in K. W. Four Cylinder Magneto. casing. With this magneto the wiring is as simple as it would be with the true high-tension form and only five wires are needed in the external circuit. Of these, four secondary leads run direct from the distributor to the plug while the remaining one is a primary ground wire having a switch in circuit through which the primary coil current may be grounded instead of going to the transformer coil, thus stopping the motor. Fig. 100.-K. W. High Tension Magneto. A Distinctive Form Utilizing Stationary Winding and Revolving Inductor Elements to Produce Current for Ignition. All magnetos do not employ a revolving winding. Some utilize a stationary coil of wire and use rotating inductor members to cause the lines of magnetic force to flow through the wire and generate a current therein. A simplified wiring diagram of the K. W. magneto, which is an igniter of this type, is shown at Fig. 99, while a sectional view of the device itself is presented at Fig. 100. The stationary coil is composed of two windings, a primary and a secondary, and is mounted in the center of the device so that the rotary inductor shaft passes through it, one inductor being placed at each side of the stationary coil. The secondary wire passes through the insulated electrode through a bridge or strap member which is connected at one end to the spark gap and at the other to a bent conductor which conveys the current to a revolving distributor arm. When the contact points are separated by the cam a current of electricity is induced in the primary coil and transformed to a hightension current in the secondary winding and is delivered to the spark plugs by the conventional form of distributor. Except for the stationary winding and the use of inductor pieces to reverse the lines of magnetism through the coil, the construction does not differ from the forms previously described. It is advanced that the stationary winding offers some advantages inasmuch as brushes are not required to collect the primary current. The function of the safety spark gap is to take care of any excess current which might damage the insulation of the winding by allowing it to go to the ground. The air gap between the points has high enough resistance so that the spark will not jump it under normal conditions, but should the voltage become suddenly increased in value, as might be the case if one of the plug wires became disconnected, it will leap this gap in preference to overcoming the resistance of the insulation of the winding. The purpose of the condenser in a magneto is the same as that used in a coil, i.e., it is interposed in the primary circuit in such a way that it is in shunt connection with the contact-breaker points and absorbs any current which would tend to produce excessive sparking. Simple Low Tension Magnetos.-Simple forms of magneto igniters have been devised for use in connection with stationary and marine engines that have not been adapted for service on the automobile power plant. Two very simple magnetos are shown at Fig. 102, these having been used to some extent in tractor work as well as on the various forms of stationary power plants employed for miscellaneous duties in the shop or on the farm. The form at A has an oscillating armature instead of the usual form of rotating Fig. 101.-Rotary Inductor with Fixed Winding at Top of Illustration and Conventional Form of Rotating Winding Shuttle Armature at Bottom, 1 |