Automobile starting and lighting
AUTOMOBILE STARTING AND LIGHTINGA Non-Technical Explanation of the Construction, Upkeep and Principles of Operation of the Electrical Equipment of Automobiles.
BY HAROLD P. MANLY
CHICAGO, FREDERICK J. DRAKE, 1918
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Automobile starting and lighting
PREFACE
Automobile Starting and Lighting has been written to give a working knowledge of the construction and action of the various parts of electrical equipment, together with a necessary understanding of the principles that govern their operation. The necessity for such a work is evident in that more than ninety-eight per cent of all cars now produced are electrically started and lighted.
Detailed explanation is given of all types of construction at present in use or that have been adopted in former installations, thus allowing the user to apply the information to future developments as well as to all those now found. By treating the subject according to the several units entering into all constructions, the entire field has been covered without the necessity of too brief explanation or such repetition as would be called for by other methods. The particular applications found in the well-known makes of apparatus have been outlined in one portion of the book.
The attention of the practically inclined user is called to the chapter on storage batteries, to the chapter describing the action of regulating and cutout devices, to the chapter on Troubles and Remedies, and to the last chapter, in which has been explained the meaning of two hundred of the words and terms generally used in starting, lighting and ignition work, and in the application of electrical science found in this field.
Detailed explanation is given of all types of construction at present in use or that have been adopted in former installations, thus allowing the user to apply the information to future developments as well as to all those now found. By treating the subject according to the several units entering into all constructions, the entire field has been covered without the necessity of too brief explanation or such repetition as would be called for by other methods. The particular applications found in the well-known makes of apparatus have been outlined in one portion of the book.
The attention of the practically inclined user is called to the chapter on storage batteries, to the chapter describing the action of regulating and cutout devices, to the chapter on Troubles and Remedies, and to the last chapter, in which has been explained the meaning of two hundred of the words and terms generally used in starting, lighting and ignition work, and in the application of electrical science found in this field.
CONTENTS
- Electric Lighting and Engine-Starting Equipment
- Lighting Dynamos and Starting Motors
- Storage Batteries
- Lamps and Wiring
- Controlling Devices, Cut-Outs and Regulators
- Drive Methods and Starting Switches
- Indicating Devices and Trouble Location
- Makes and Types of Equipment
- Electrical Words and Terms
CHAPTER I - ELECTRIC LIGHTING AND ENGINE-STARTING EQUIPMENT
The fundamental principles employed in all of the various makes of automobile electrical equipment are the same regardless of the particular application chosen by the designers and builders. All systems must provide parts which accomplish certain results essential to the operation of the system as a whole.
In some cases a single part may perform two or more functions, in other cases separate parts will be provided for each function, while in still other cases some of the parts may apparently be absent. Nevertheless, every successful electrical installation must cause the same actions to take place, and parts must be provided that will bring about the effects necessary for continued operation.
It is first of all necessary to cause a flow of electric current, and this is done by the dynamo, or generator, operated by the gasoline engine. A certain amount of power is required to run the dynamo, and this power is taken through gears, chains or belts between the engine and dynamo or by mounting the dynamo on the engine crankshaft. The dynamo may be defined as the mechanism that changes the mechanical power received from the engine into electric current.
It is evident that the engine cannot always be running when current is required, inasmuch as it is necessary to light the lamps under this condition and to start the engine from rest. It is, therefore, necessary to accumulate and store the surplus energy that is produced during the time the engine runs under its own power, and this is accomplished by the storage battery which is a vital part of every electrical equipment.
Having a source of current and a means of retaining a part of the energy until it is needed, it remains to attach the parts that consume current in lighting, starting, ignition and control of the automobile. These parts include the various lamps, an electric motor for cranking the engine, and in many cases the parts for ignition, gear shifting, carburetor heating and the many electrical accessories which are found in use.
Thus, the four essentials of the electric system are dynamo, battery, lights and starting motor. In order to allow the operator of the car to use these parts, and to cause them to perform their duties properly and without danger to themselves, certain controlling and regulating devices are necessary.
For convenience in further explanation, the electrical apparatus of the car will be divided into three principal parts (Figure 1), the charging system, the lighting system, and the starting system. The charging system will include the dynamo, the battery, and all the parts required for their operation and use. The lighting system will include the lamps and their wiring, also the parts needed for their control. The starting system will include the starting motor, the starting switch and the necessary wiring.
In order to prevent confusion, the following usages have been adopted and will be followed throughout this work. While both words refer to the same instrument, the word “dynamo” will be used in preference to “generator” whenever the dynamo-electric machine is used to cause a flow of current. The word "motor" will refer to the electric starting motor and not to the automobile engine. The combination of dynamo and motor in one unit will be called a "motor-dynamo." For an explanation of the meaning of electrical words and terms used in starting and lighting, see Chapter IX.
CHARGING SYSTEM
Dynamo - The dynamo consists of a revolving element, operating in connection with a stationary element. The rotation of one of these parts with reference to the other generates a flow of electric current in one of them, called the armature, and the current then passes from the armature out of the dynamo to the battery and other electrical parts. The second element is called the field magnet, and provides the necessary magnetism.
The usual construction, Figure 2, makes the armature the rotating element, and the most common form of armature is built by mounting on a shaft a sufficient number of soft iron discs to make a cylinder, or else a cylindrical piece of soft iron is used in one piece. This part is called the armature core. Running lengthwise of the core are a number of grooves or slots, these slots being of sufficient width and depth to allow a quantity of insulated wire to be wound on the core and in the slots. The coils formed by this wire are called the armature windings, and it is in these windings that the current flow is first generated. Various forms are adopted for the field magnet, the shape depending on the size and mounting that will be required for the particular machine being designed. If a single magnet is used, that is, a magnet having but two ends, these ends are placed in such a position that they are at opposite sides of the armature core and the magnetism that passes from one end to the other must therefore pass across and through the armature core. The ends of the magnet are curved to bring them close to the armature, and the cylindrical passage between them, in which the armature rotates, is called the armature tunnel.
Should the magnets be formed with four or six ends, as is often the case, the ends are placed so that they form pairs on opposite sides of the armature and are directly across from each other. The machine is then called a four-pole or six-pole dynamo (Figure 3), depending on whether there are four or six magnet ends placed around the armature.
The magnets that produce the field are made from soft iron, and the soft iron, called the magnet core, is surrounded with a coil of insulated wire. When a flow of current passes through this wire, the soft iron becomes a magnet, this type being known as an electro-magnet, as differing from a permanent magnet, which is made from hardened steel. The coil of wire around the magnet core is called the field winding, and the current that passes through this winding to make the core magnetic is secured by taking a part of the current generated in the armature.
As the armature rotates between the field magnet poles, the current caused to flow through each one of the armature coils travels in one direction through the wire while the armature and coil make a half revolution, and then, on the next half revolution, the current is caused to pass in the opposite direction through the winding. A current that reverses its direction of flow in this way is called an alternating current, and is not suitable for battery charging purposes because of the fact that the reversal of flow would take out as much current as it would put into the battery.
In order to change this alternating current into a flow that always travels through a wire in one direction, the commutator is used. The current having a continuous direction of travel is called direct current, and is the only form suitable for battery chaining.
The commutator consists of a number of copper bars arranged in a circle around one end of the armature shaft and fastened to the shaft so that they turn with it. These bars are separated from each other by some material that will not carry electric current; in other words, are insulated from each other. Each pair of copper bars is fastened to an armature winding coil that rests in one pair of slots, and the other bars are fastened to the other coils of wire that form the armature. This construction makes it necessary to have double the number of commutator bars that there are armature windings, each pair of bars forming the two ends of one coil on the armature.
Because of the fact that a flow of current is generated in an armature coil while it is passing across one of the magnet poles, one electrical impulse is generated in each direction by a two-pole machine, as already mentioned. One complete revolution of the armature. Figures 4 and 5, will cause both sides of the coil, which means the whole coil, to pass first across the end of one pole of the magnet, then across the end of the other pole. This action will send an impulse to the commutator bars first in one direction, then in the other.
Two brushes, made from some material that carries electricity with ease, are placed so that they rest against the surface of the commutator bars and at opposite points on the commutator surface. The brushes are therefore in contact with opposite bars at the same time, and with the two ends of the armature coil. Any flow of electric current generated in the armature winding will pass into these brushes.
Now, bearing in mind the fact that the current reverses each half revolution, and also the fact that the commutator bar in contact with one brush at one position will have changed to the other brush when a half revolution has been made, it will be seen that the current will always be given to the brushes in the same direction. This is true because, while the direction of flow has reversed, the position of the commutator bars with reference to the brushes has also.
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Automobile starting and lighting
In some cases a single part may perform two or more functions, in other cases separate parts will be provided for each function, while in still other cases some of the parts may apparently be absent. Nevertheless, every successful electrical installation must cause the same actions to take place, and parts must be provided that will bring about the effects necessary for continued operation.
It is first of all necessary to cause a flow of electric current, and this is done by the dynamo, or generator, operated by the gasoline engine. A certain amount of power is required to run the dynamo, and this power is taken through gears, chains or belts between the engine and dynamo or by mounting the dynamo on the engine crankshaft. The dynamo may be defined as the mechanism that changes the mechanical power received from the engine into electric current.
It is evident that the engine cannot always be running when current is required, inasmuch as it is necessary to light the lamps under this condition and to start the engine from rest. It is, therefore, necessary to accumulate and store the surplus energy that is produced during the time the engine runs under its own power, and this is accomplished by the storage battery which is a vital part of every electrical equipment.
Having a source of current and a means of retaining a part of the energy until it is needed, it remains to attach the parts that consume current in lighting, starting, ignition and control of the automobile. These parts include the various lamps, an electric motor for cranking the engine, and in many cases the parts for ignition, gear shifting, carburetor heating and the many electrical accessories which are found in use.
Thus, the four essentials of the electric system are dynamo, battery, lights and starting motor. In order to allow the operator of the car to use these parts, and to cause them to perform their duties properly and without danger to themselves, certain controlling and regulating devices are necessary.
For convenience in further explanation, the electrical apparatus of the car will be divided into three principal parts (Figure 1), the charging system, the lighting system, and the starting system. The charging system will include the dynamo, the battery, and all the parts required for their operation and use. The lighting system will include the lamps and their wiring, also the parts needed for their control. The starting system will include the starting motor, the starting switch and the necessary wiring.
In order to prevent confusion, the following usages have been adopted and will be followed throughout this work. While both words refer to the same instrument, the word “dynamo” will be used in preference to “generator” whenever the dynamo-electric machine is used to cause a flow of current. The word "motor" will refer to the electric starting motor and not to the automobile engine. The combination of dynamo and motor in one unit will be called a "motor-dynamo." For an explanation of the meaning of electrical words and terms used in starting and lighting, see Chapter IX.
CHARGING SYSTEM
Dynamo - The dynamo consists of a revolving element, operating in connection with a stationary element. The rotation of one of these parts with reference to the other generates a flow of electric current in one of them, called the armature, and the current then passes from the armature out of the dynamo to the battery and other electrical parts. The second element is called the field magnet, and provides the necessary magnetism.
The usual construction, Figure 2, makes the armature the rotating element, and the most common form of armature is built by mounting on a shaft a sufficient number of soft iron discs to make a cylinder, or else a cylindrical piece of soft iron is used in one piece. This part is called the armature core. Running lengthwise of the core are a number of grooves or slots, these slots being of sufficient width and depth to allow a quantity of insulated wire to be wound on the core and in the slots. The coils formed by this wire are called the armature windings, and it is in these windings that the current flow is first generated. Various forms are adopted for the field magnet, the shape depending on the size and mounting that will be required for the particular machine being designed. If a single magnet is used, that is, a magnet having but two ends, these ends are placed in such a position that they are at opposite sides of the armature core and the magnetism that passes from one end to the other must therefore pass across and through the armature core. The ends of the magnet are curved to bring them close to the armature, and the cylindrical passage between them, in which the armature rotates, is called the armature tunnel.
Should the magnets be formed with four or six ends, as is often the case, the ends are placed so that they form pairs on opposite sides of the armature and are directly across from each other. The machine is then called a four-pole or six-pole dynamo (Figure 3), depending on whether there are four or six magnet ends placed around the armature.
The magnets that produce the field are made from soft iron, and the soft iron, called the magnet core, is surrounded with a coil of insulated wire. When a flow of current passes through this wire, the soft iron becomes a magnet, this type being known as an electro-magnet, as differing from a permanent magnet, which is made from hardened steel. The coil of wire around the magnet core is called the field winding, and the current that passes through this winding to make the core magnetic is secured by taking a part of the current generated in the armature.
As the armature rotates between the field magnet poles, the current caused to flow through each one of the armature coils travels in one direction through the wire while the armature and coil make a half revolution, and then, on the next half revolution, the current is caused to pass in the opposite direction through the winding. A current that reverses its direction of flow in this way is called an alternating current, and is not suitable for battery charging purposes because of the fact that the reversal of flow would take out as much current as it would put into the battery.
In order to change this alternating current into a flow that always travels through a wire in one direction, the commutator is used. The current having a continuous direction of travel is called direct current, and is the only form suitable for battery chaining.
The commutator consists of a number of copper bars arranged in a circle around one end of the armature shaft and fastened to the shaft so that they turn with it. These bars are separated from each other by some material that will not carry electric current; in other words, are insulated from each other. Each pair of copper bars is fastened to an armature winding coil that rests in one pair of slots, and the other bars are fastened to the other coils of wire that form the armature. This construction makes it necessary to have double the number of commutator bars that there are armature windings, each pair of bars forming the two ends of one coil on the armature.
Because of the fact that a flow of current is generated in an armature coil while it is passing across one of the magnet poles, one electrical impulse is generated in each direction by a two-pole machine, as already mentioned. One complete revolution of the armature. Figures 4 and 5, will cause both sides of the coil, which means the whole coil, to pass first across the end of one pole of the magnet, then across the end of the other pole. This action will send an impulse to the commutator bars first in one direction, then in the other.
Two brushes, made from some material that carries electricity with ease, are placed so that they rest against the surface of the commutator bars and at opposite points on the commutator surface. The brushes are therefore in contact with opposite bars at the same time, and with the two ends of the armature coil. Any flow of electric current generated in the armature winding will pass into these brushes.
Now, bearing in mind the fact that the current reverses each half revolution, and also the fact that the commutator bar in contact with one brush at one position will have changed to the other brush when a half revolution has been made, it will be seen that the current will always be given to the brushes in the same direction. This is true because, while the direction of flow has reversed, the position of the commutator bars with reference to the brushes has also.
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Automobile starting and lighting
