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shaft over. Similarly as soon as the engine starts revolving under its own power the device becomes a generator. The wiring is extremely simple, as is outlined at Fig. 154. This shows only the wiring of the generating and motor starting functions and does not show any lighting or ignition circuit, though these may be taken
Fig. 155.—One Type of Westinghouse Starting Motor and Parts Com
prising the Assembly.
from the battery in the usual manner. The lighting system operates on six volt current, though the starter requires a 12 cell or 24 volt battery. The lighting current is taken from only three cells of the battery.
The Westinghouse motors, generators, and motor-generators are designed particularly for their location alongside the engine, under the hood. As they are entirely enclosed, they are not affected by dirt, oil, gasoline or water. The end frames that carry the bearings are machined magnalium castings of substantial design, and are each fastened to the frame by heavy screws with lock washers, effectively preventing vibration from disturbing the alignment of the bearings. The size and proportions of the machines are such that they can be conveniently located without interfering with the balance of the car equipment. The frame is
of cast steel (except the smaller motors), which not only gives ample strength, but because of its high magnetic permeability results in a saving in weight.
The armature is of the laminated drum type, with windings laid in slots. A special insulation is used, which after treatment makes the armature a solid mass that does not soften even at a continuous temperature of 250 degrees Fahrenheit. It will stand even higher temperature for short periods. The insulation and treatment absolutely prevents the winding from working loose under vibration, and makes it impervious to oil, water, and gasoline. The design provides for easy removal of the armature.
The field coil winding is also treated with the same insulating composition and cannot possibly jar loose. Wherever possible, aluminum wire is used to reduce the weight. The insulation is applied by a special process that saves space.
The commutator and brushes are of proper proportions and of sufficient size to last for years without renewal of either. The brushes are mounted firmly, and can be removed and replaced without the use of tools. The current is carried to the brush by a low-resistancce copper shunt, and not by the brush spring. Proper silver-tipped connections are made by the brushholders when the brushes are inserted.
The shaft has a large diameter. The motor shaft has either square or taper end, as desired. A Woodruff key is provided, and a large locknut and washer, held by a spring cotter.
The bearings of the generators are magneto type ball bearings of a high grade, requiring minimum space. Starting motors are provided with either ball bearings or plain sleeve bearings. A starting motor receives such a small amount of actual running that ball bearings are a refinement not actually required.
The Westinghouse generators are shown at Figs. 149 and 150. The simple form of motor shown at Fig. 155 is intended for use with external reduction gearing. That depicted at Fig. 156 has internal planetary gearing to give the required speed reduction between motor armature shaft and engine crankshaft.
Generator Driving Methods.- When electric lighting was first applied to automobiles it was not considered necessary to drive the generators by positive connection, and the early devices were furnished with pulleys for flat or V belt drive. At the present time it is considered highly important to provide a positive mechanical connection that will not slip between the generator and the engine crankshaft. The common systems where the generator is a separate unit from the starting motor and in those forms where the
Fig. 157.—Plan View of 1916 Maxwell Chassis Showing Location of Starting System Parts. Note Belt
Drive to Generator Driving Shaft.
spur gears and chain, as shown at A-2, or by a chain to a shaft connected with the timing gear, as in A-3. The method at A-4 is a very popular one, including a reduction to an intermediate shaft, which carries a sliding pinion designed to engage the gear on the flywheel rim. The method at A-5 is used with the Rushmore starter, the
Fig. 159.—Diagram Showing Methods of Transmitting Power of Starting
Motor to Gasoline Engine at A. Simplified Diagram at B Depicts
pinion being brought into direct engagement with the gear on the flywheel by the axial movement of the armature when the current is supplied to the field winding. The method at A-6 permits of attaching the starting motor securely to the frame side member at a point near the gear box, where it will be out of the way and not interfere with the accessibility of the power plant. When mounted