THE BERLING MAGNETO
The Berling magneto is a true high tension type delivering two impulses per revolution, but it is made in a variety of forms, both single and double spark. Its principle of action does not differ in essentials from the high tension type previously described. This magneto is used on Curtiss aviation engines and will deliver sparks in a positive manner sufficient to insure ignition of engines up to 200 horse-power and at rotative speeds of the magneto armature up to 4,000 r. p. m. which is sufficient to take care of an eight-cylinder V engine running up to 2,000 r. p. m. The magneto is driven at crank-shaft speed on four-cylinder engines, at 11⁄2 times crank-shaft speed on six-cylinder engines and at twice crank-shaft speed on eight-cylinder V types. The types “D” and “DD” BERLING Magnetos are interchangeable with corresponding magnetos of other standard makes. The dimensions of the four-, six- and eight-cylinder types “D” and “DD” are all the same.
Fig. 63.—Type DD Berling High Tension Magneto.
The ideal method of driving the magneto is by means of flexible direct connecting coupling to a shaft intended for the purpose of driving the magneto. As the magneto must be driven at a high speed, a coupling of some flexibility is preferable. The employment of such a coupling will facilitate the mounting of the magneto, because a small inaccuracy in the lining up of the magneto with the driving shaft will be taken care of by the flexible coupling, whereas with a perfectly rigid coupling the line-up of the magneto must be absolutely accurate. Another advantage of the flexible coupling is that the vibration of the motor will not be as fully transmitted to the armature shaft on the magneto as in case a rigid coupling is used. This means prolonged life for the magneto.
The next best method of driving the magneto is by means of a gear keyed to the armature shaft. When this method of driving is employed, great care must be exercised in providing sufficient clearance between the gear on the magneto and the driving gear. If there should be a tight spot between these two gears it will react disadvantageously on the magneto. The third available method is to drive the magneto by means of a chain. This is the least desirable of the three methods and should be resorted to only in case of absolute necessity. It is difficult to provide sufficient clearance when using a chain without rendering the timing less accurate and positive.
Fig. 64.—Wiring Diagrams of Berling Magneto Ignition Systems.