disconnected either through accident or neglect, this fuse will burn, thus protecting generator and field against excessive voltage, which would result if the field circuit were not opened.

To start the engine the operator presses the starting switch, which puts the motor armature into motion, engages the gearing and clutch, and turns the engine over. When the engine is running under its own power the clutch and engine are automatically disengaged and the unit operates only as a generator. The lamp load of the car is carried by the generator at about 12 miles per hour. As a "tell-tale" an indicator is employed, from which the operator may determine whether the generator is working properly. A simple lighting switch is used for turning on any combination of lamps. No side lamps are used, as the head lamps contain small independent bulbs for signal lamps. The two-wire system of wiring is used. It has been carefully developed, resulting in a very simple layout, as may be seen from the accompanying wiring plan of the system as applied to the six-cylinder National car.

Faults in Motors and Generators.-While every effort has been made by the manufacturers of electric starting and lighting systems to have the various units function as nearly automatically as possible, it will be evident that some attention will be needed by the various units. The generator should be looked over from time to time and should any carbon dust be worn from the brushes by the commutator and deposited in the lower part of the casing it should be blown out with compressed air. It is stated that an accumulation of this dust may result in a ground to the generator case or produce a short circuit between the brush carrier and case. If the commutator is blackened or rough it must be smoothed down with fine sandpaper while the armature is rotating. Never use emery cloth for this purpose. After smoothing down the commutator remove all particles of metal which may bridge across between the copper segments. The insulating material between the commutator segments should not be higher than the surfaces of the segment, and if any of it projects it must be filed down slightly lower than the copper pieces by using a small file.

The brushes are the part of the generator that demand the most attention and to which most of the troubles in devices of this kind

are due. They should be examined to see that they are in perfect contact with the commutator and that they do not stick in the brush holders. Any dirt or grease on the brush assembly should be removed. One of the most fertile causes of poor brush contact with the commutator is on account of insufficient spring tension. When examining the brushes care should be taken to see that these are maintained positively in contact with the copper segments. Care should be taken not to have the spring pressure too great, as this would produce rapid depreciation of the brushes and heating of the commutator. Brushes that have worn down till they are short must be replaced with new ones. When replacing brushes be sure that they fit the commutator surface exactly over the whole area of the end of the brush, and in all cases use brushes for replacement furnished by the maker of the generator. In some generators, shunt connections, which are called "pigtails," are used for connecting the brushes. If the new brushes furnished by the factory have these connections attached care should be taken to make the connection exactly the same as on the old brushes.

It is imperative that the commutator be kept clean, as any oil or grease on the segments will collect carbon dust and produce short circuiting. The brush holders should be entirely insulated from the carrying case, and if any of the insulating bushings, washers or plates are found defective they must be replaced with new ones. Should the battery or generator be disconnected for any reason, do not operate engine again until they are connected. Never run a generator unless connected to the battery. With the engine running and lamps burning, if the amperemeter hand stays at zero it indicates that the generator is producing exactly the same amount of current as the lamps are consuming. If the hand is on the discharge side of zero it means that the current-consuming units are burning more than the generator is producing. If the pointer is on the charging side of the scale it shows that the generator is producing more current than is being used by the lamps.

The starting motor is subject to the same electrical troubles as the generator is. These are grounds, short circuits, brush and commutator troubles. Defects in either the motor or generator drive are of a purely mechanical nature and can be easily located by any

competent repairman. The centrifugal governor used on many generators is not apt to give any trouble unless some of the parts fail or the action becomes clogged with oil and grease. If the springs tending to return the weights are broken or become weakened the generator will not deliver the proper amount of current because the drive will not be positive. Any accumulation of oil that will interfere with proper frictional adhesion between the clutch parts where a governor is employed will also result in failure to drive.

Faults in Wiring.-In the two wire system every wire, connector and socket must be insulated from the car and should not be in metallic contact at any point except at the terminal. It is imperative that all wires be insulated from each other and the car frame except at points where permanent connections are made. All connections should be soldered to insure positive contact and securely wrapped with insulating tape. The wires must be held. securely by means of cleats of insulating material and must be mounted in such a way that there is no possibility of sharp metal corners or edges wearing through the insulation and causing grounds or short circuits.

All wiring should be protected from the rotting action of grease, oil and water, and when the wiring is run where these substances are apt to accumulate, the regular insulation should be supplemented by a conduit of insulating material such as circular loom or fiber tubing, or armored cable should be used. All wires should be so installed that there is no danger of interference between them and operating rods and levers. The abrasion of these members will wear through the insulation, and result in short circuits. Brass or copper terminal connections should be used at all points and no connection should be made by winding the strands of wire around the terminal. One or more of the strands may bridge across the terminal or to some metal part and cause a short circuit or ground. Special care should be taken with the connections in the lamps and other points. By the term "short circuit" electricians mean that two wires of opposite polarity are in metallic contact. Under such conditions the storage battery will be discharging and there will be no lights at the lamps. A short circuit may occur at any point

in the wiring system, but is usually found at terminals that have been carelessly made or by worn insulation on wires.

A short circuit will be indicated by the position of the amperemeter pointer. Always note the position of the index hand of that instrument when the car is stopped. With the engine at a standstill and no lamps burning the hand should point to zero. If it does not the amperemeter is either out of calibration or there is a leak of current from the battery at some point in the wiring. To ascertain if the amperemeter is correct, uncouple one of the battery terminals of the lighting system. Obviously, if the hand swings to zero, the trouble is leakage of current, which should be immediately corrected after the trouble is located. If the index does not point to zero when the battery terminal is disconnected, the instrument is out of calibration, and while this does not affect the operation of the system it should be taken into account when reading the amperemeter. If the engine backfires when the ignition is interrupted and it makes one or two revolutions in the reverse direction, the amperemeter pointer may be found at the extreme of the scale on the discharge side. This is caused by the circuit breaker contact being held closed and means a short circuit of the battery through the generator winding. This must be corrected at once by momentarily disconnecting one of the generator wires or starting the engine. If the wires are removed from the generator for any reason make sure that they are connected to the same terminals as they were originally. If the wires are reversed the amperemeter will indicate a dead short circuit by swinging to the extreme on the discharge side of the scale when the engine is started, and if this defective condition is not corrected the battery will be soon discharged. In case of a short circuit examine all of the wires connected to the battery terminals and to the lighting switch. Make sure that the insulation is perfect and that it has not been cut through at any point. Whenever any wires are removed from any of the units always mark the terminals and the wire so that they will be replaced exactly as they were originally. If a short circuit exists when all the switches are opened, if one takes off a battery terminal and makes and breaks contact between the wire and that member a small spark will be in evidence. If no sparking occurs,

connect up the terminal to the battery and then with the engine at a standstill close the switches to the lighting circuit one at a time and watch the amperemeter closely as each switch makes contact. If the pointer does not move far from zero it shows that the current consumption is normal; if, however, the pointer swings to the extreme of the discharge scale it is evident that a short circuit exists somewhere in the circuit just brought into action. All the circuits can be tried in this manner one at a time. If the amperemeter indicates only a normal amount of current consumption for the various lighting circuits it is apparent that no further search is necessary. If, however, the needle indicates a short circuit on one or more of the switch positions, examine the wires carefully for the circuits at fault, and if the trouble does not exist there it may be located in the lamp socket, the connector or the bulb itself. In case one or more lamps fail to burn the trouble is due to either a broken wire or a defective connection at the switch, connectors or lamp sockets or a bulb or fuse is burnt out.

The following instructions relative to the care of the lamps and storage battery of the Auto-Lite system are taken from an instruction book prepared by this company and apply to similar components of all systems. Complete directions for the care and charging of storage batteries are given in the preceding chapter, but at the same time a review of the important points to keep in mind in connection with the maintenance of the batteries used in lighting and starting systems will prove of value to the motorist or repairman who does not desire to go thoroughly into the subject of storage battery charging or maintenance.

To clean head and side lamp reflectors, remove from lamp body and carefully blow out any dust which may have collected on the reflecting surfaces. Then dip a small piece of absorbent cotton in alcohol and lightly wipe over the surface-always from the back to the front. To focus the lamps, open the swinging front of the lamp and direct the light upon some smooth vertical surface at a distance of about ten feet. Loosen the adjusting screw on the slide at the rear of the reflector, and move the bulb and socket out and in until all rings disappear in the illuminated area. Then tighten down the adjusting screw and close the lamp. Any further adjust