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HOW TO INSTALL Electric Bells, Annunciators, and Alarms.
HOW TO INSTALL Electric Bells, Annunciators, and Alarms.
INCLUDING Batteries, Wires and Wiring, Circuits, Pushes, Bells, Burglar Alarms, High and Low Water Alarms, Fire Alarms, Thermostats, Annunciators, and the Location and Remedying of Troubles. BY NORMAN H. SCHNEIDER, Author of “The Study of Electricity for Beginners,” “Care and Handling of Electric Plants,” etc., etc. SECOND EDITION, ENLARGED NEW YORK SPON & CHAMBERLAIN, 123 LIBERTY STREET LONDON E. & F. N. SPON, Limited, 57 HAYMARKET, S.W. 1913 [No. 4] Copyright 1904 Copyright 191
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PREFACE
PREFACE
Among all the applications of electricity to domestic or commercial uses, few are as widespread as the electric bell. Practically every building used for a dwelling, storage or manufacture requires an electric bell, annunciator or alarm system. This book was written to explain in practical language how an electric bell system operates and how it is installed; its success shown by its large sale has resulted in this new edition which brings the subject up to date. Many new diagrams of annunciator
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INTRODUCTION
INTRODUCTION
An electric bell depends for its action on the fact that a piece of iron wound with insulated wire becomes a magnet and will attract another piece of iron just so long as an electric current is allowed to travel through the wire. The instant the current ceases, the magnetism also ceases, and the attracted piece of iron (termed the armature) is no longer held in contact. The general construction of an electric bell is shown in Fig. 1 . M M are coils of insulated wire wound on soft iron cores. A i
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The Battery Cell.
The Battery Cell.
In setting up this cell about four ounces of sal ammoniac (chloride of ammonia) are put into the jar and enough water added to come about half way up the jar. The porous jar P and the zinc Z are then inserted, and the cell is ready for use in a few minutes after the liquid has soaked through the earthenware into the carbon-manganese mixture. Water is often poured into the porous jar through holes in its top to hasten this wetting. Wires are clamped by nuts or set-screws to the negative terminal
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The Dry Cell.
The Dry Cell.
The Leclanche cell being a cell with much free liquid is liable to dry up if not watched. The dry cell ( Fig. 3 ) is a modern form of the Leclanche where the liquid is held by an absorbent material, such as blotting paper, or plaster. A typical dry cell A is shown in the figure. An outside case of zinc is lined with blotting paper dampened with chloride of zinc and sal ammoniac. A carbon rod is then inserted in the centre and packed around with carbon dust and peroxide of manganese. The latter m
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The Gravity Daniell Cell.
The Gravity Daniell Cell.
The gravity cell, Fig. 4 , has a zinc block Z suspended from the side of the jar and a number of copper leaves C standing on edge at the bottom. A quantity of bluestone (sulphate of copper) is poured over the copper leaves and the jar filled with water. During the working of this cell, copper is deposited on the copper plate, and sulphate of zinc formed at the zinc. To hasten the action a small quantity of zinc sulphate can be added to the solution when setting up the cell. The name of this cell
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E. M. F.
E. M. F.
The e. m. f. of a gravity cell is within a fraction of one volt, its current nearly one-half ampere. Warmth makes it give a greater current; on no account let a gravity cell freeze....
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Resistance of a Cell.
Resistance of a Cell.
The fluids in a cell do not conduct electricity as well as copper does; they offer more resistance and thus reduce the current output. The internal resistance of a cell may be lowered by using large zinc plates curled around the porous pot. The Samson cell has a large zinc plate bent in the form of a cylinder, the carbon-manganese combination standing in the centre of it. The dry cell also has a large zinc, the internal resistance being thus much lowered, the current output is increased. This is
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Grouping of Cells.
Grouping of Cells.
Cells may be grouped in a battery to get increased voltage, or increased amperage. When connected for the former, they are in series, the carbon of one is connected to the zinc of the next, and so on. If all the carbons are connected together and all the zincs, they are in multiple, and will give the same voltage as of one cell but the combined amperage of all. In ordinary bell work the series is the general connection, the higher the resistance of the circuit, or the longer the wires, the more
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Electric Bells.
Electric Bells.
The two main types of house bells are the iron box and the skeleton. The iron box has a cast-iron frame, or base, and a cast- or stamped-iron cover over the mechanism. The skeleton bell has an iron frame but no cover, and is generally better finished and more expensive than the iron box bells. For fire alarm purposes, mechanical bells or gongs are made, in which a clockwork mechanism causes the hammer to strike the gong upon being released by electromagnetism. Marine or waterproof bells have an
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The Single-stroke Bell.
The Single-stroke Bell.
The bell before described, and again shown in Fig. 5 , is a vibrating, or trembling, bell. It is often desired to have the hammer give only one stroke for each pressure of the push, as in signaling with a code of taps; in this case a single-stroke bell is used. The circuit from the binding posts is then directly through the magnet coils without any break at the contact screw, as in Fig. 6 . In adjusting such a bell to give a clear sound, press the armature up against the iron magnet cores and th
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The Shunt Bell.
The Shunt Bell.
There is a form of bell, Fig. 7 , known as the shunt, or short circuit bell, which is often used when two or more are to be connected in series, as will be seen in the description of circuits. In this bell the circuit through the magnets is not broken at the contact screw, but the forward movement of the armature short circuits the coils. As the short, or shunt, circuit is very much lower in resistance than the wire on the magnet coils, the main current flows around the latter and they do not be
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The Differential Bell.
The Differential Bell.
Sparking at the breaking contacts of an electric bell is detrimental to the platinum points, and many remedies have been devised to overcome it. Sparking is due to the self-induction of one turn of the wire coil acting on its neighbor, and this property is utilized in the gas engine, or gas-lighting spark coil, where a fat spark is needed to ignite gas. The differential bell has two windings in opposite directions. The action of one would be to produce an N-pole at one end and an S-pole at the o
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Continuous-ring Bell.
Continuous-ring Bell.
In some classes of bell work, such as burglar alarms, it is desired that the bell when once started shall continue to ring until stopped by the person called. In this case a continuous-ringing bell is needed, such as in Fig. 8 . When the push P is pressed, the current flows in the usual way through contact screw L , armature spring A , magnet coils M M , battery B , back to P , and the bell rings. But on the first forward movement of the armature it releases the spring contact S , which flies fo
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Waterproof Bells.
Waterproof Bells.
In Fig. 9 is an example of a waterproof bell where the mechanism is almost all entirely encased in a waterproof brass case. The circuit is made and broken inside the case, but the magnet cores project through it and act on a second armature placed outside. This second armature carries the hammer which strikes the gong and is governed in speed by the contact-breaking armature inside....
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Forms of Bell Gongs.
Forms of Bell Gongs.
In order to provide a variety of sounds, bells are provided with gongs of various shapes. Fig. 10 shows the ordinary form of gong. Fig. 11 , a tea gong; Fig. 12 , a cow gong; and Fig. 13 , a sleigh bell. A coil of steel wire is also used, as in Fig. 14 , which on being struck by the hammer gives a pleasant but not loud tone....
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The Buzzer.
The Buzzer.
The buzzer is the mechanism of a vibrating bell less the hammer and gong. As the armature vibrates it makes a buzzing noise which does not carry as far as the sound from a struck gong. It is used chiefly for a desk call and in telephone exchange work, or any place where general attention is not desired to the signal....
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Operating Bells at a Distance.
Operating Bells at a Distance.
When it is desired to ring a bell situated at a considerable distance from the push, the resistance of the line becomes objectionable. On lines of 500 feet, No. 18 copper wire and upwards, the battery necessary would be very large, two small batteries and a relay would prove more satisfactory. In Fig. 15 the circuit of a simple form of relay is given. An adjustable contact screw C is placed where an extension S of the armature A can strike it. This extension is provided with a platinum contact.
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Reducing Resistance of a Bell.
Reducing Resistance of a Bell.
Sometimes it is desired to reduce the resistance the bell coils offer to the current, the bell then working over a very short line with few cells of battery. Or the bell coils may have been wound with fine wire for large battery voltage and a long line. The bell coils may be put in multiple, the current then dividing and one-half going through each spool. Untwist the joint between the spools near the yoke or iron bar to which the spools are attached. Join one of these ends to the wire at the arm
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The Push Button.
The Push Button.
Push buttons, or pushes, are made in a variety of forms, with metal, wood, hard rubber, or porcelain bases. Fig. 16 has a metal base, and is suitable for a front door. Fig. 17 is a wooden pear push, and is attached at the end of a cord which has the two conductors braided in it, each, however, having its own insulation. Fig. 18 is a plate push for an outside door. Fig. 19 is either of metal, wood, or porcelain, and is the shape most commonly used. A three-point push has three contact springs. On
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Indicating Push Button.
Indicating Push Button.
A push button is made which contains in the base a small electromagnet in series with the line. An armature on a spring is fixed near the magnet poles. When the push is depressed, the current travels through this electromagnet, and as the circuit is made and broken at the distant bell, it is also interrupted in the electromagnet. The armature vibrates in unison with the bell and thus gives an audible indication that the bell is ringing....
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The Wire.
The Wire.
The size of the copper wire used in bell work is No. 16, or No. 18, B and S gauge, and sometimes smaller, such as No. 20 to 22. But smaller wire than No. 18 has too much resistance, and would necessitate a larger battery power, even if its mechanical strength were not too low. The insulating coverings are cotton saturated with paraffin wax or compounds. The covered wires are variously known as annunciator, office, or weatherproof wire, these terms being mostly for distinction of the coverings an
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Joints.
Joints.
Upon the care with which a joint is made much depends, a loose or poorly made joint will offer much resistance to the current. The correct way to start a joint in annunciator, or office, wire is shown in Fig. 22 . About three inches of each wire to be joined is bared of its insulation and scraped bright. The ends are then bent at right angles to each other, hooked together and one end firmly twisted around the other, as shown in Fig. 23 . Any projecting pieces are cut off, and the joints should
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Running the Wires.
Running the Wires.
To detail all the operations of installing a complex system of bell, alarm and annunciator wires would be impossible from the reasons that conditions vary and space is limited. General directions will then only be given to enable the inexperienced to run such wires as may be needed in ordinary domestic work and to guard against the most common causes of failure. Wires may be run in tin tubes to prevent the depredations of rats and mice, or they may be run with simply their own covering for prote
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Combinations of Bells and Pushes.
Combinations of Bells and Pushes.
One of the wires in a bell circuit may be replaced by the ground ( Fig. 26 ). Connection may be made to a gas or water pipe or to a metal plate buried deep in damp earth. Any wire fastened to such a plate must be thoroughly soldered to it or a voltaic action will be set up, which will eat it away at the point of contact. When one bell is to be rung from two or more points the pushes are to be connected in multiple ( Fig. 27 ) as if they were in series; all would have to be closed to complete the
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Faults in Bells.
Faults in Bells.
On examining many electric bells it will be noted that only one binding post is insulated from the frame when the latter is of iron ( Fig. 34 ). As the armature spring S is in electrical connection with the frame F by reason of its metal screws and support, the circuit may run from the insulated post U to the magnet coils, thence through the insulated contact screw C through the armature spring (when it is making contact) and through the frame to the uninsulated post I . This saves labor, wire a
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Faults in Line.
Faults in Line.
In looking for a fault in a bell circuit make sure the battery is working; if only one or two cells, put the ends of two wires attached to the terminals on the tongue: a metallic taste will indicate current. Then see that the circuit wires are firmly clamped in the terminals and no dirt or corrosion on the connections. Next examine the push button and see that the wire connections at the springs are perfect. If there is no movement of the bell at all when the push is pressed in, take a pocket kn
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Fire Alarms.
Fire Alarms.
Thermostats, heat alarms and fire alarms are all practically the same, the term thermostat being applied principally to the apparatus which closes the electrical circuit. Thermostats act on the principle that heat causes expansion whether of substances, liquids, or gases. The degree in which different substances expand varies for the same increase in temperature. This fact is used in a common form of thermostat shown in Fig. 38 . A strip of wood or hard rubber R has a strip of thin sheet metal S
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Water Level Alarms.
Water Level Alarms.
Where it is desired to signal the rising or falling of water in a tank above or below a given point, a water level indicator as in Fig. 41 may be used. A hollow ball H is mounted on the end of a rod which slides vertically in guides, not shown. Adjustable stops S S press against a spring arm R , pressing it up or down, according as the water level is rising or falling. If rising, R makes contact with the adjustable screw A , if falling, with D , in both cases completing the electrical circuit of
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Burglar Alarms.
Burglar Alarms.
A burglar alarm is a device for indicating the opening of a door or window, by the ringing of a bell or operation of an annunciator. The contact apparatus at the points to be protected may either open an electrical circuit or close one, in the latter case being mere modifications of push buttons. The simplest form is the latter or open-circuit method. The spring contact to be inserted in the door jamb or window frame is so constructed that while under pressure the contacts are kept apart and the
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Door Trip Alarm.
Door Trip Alarm.
A swinging contact door trip can be attached over a door to ring a bell when the door is opened. In Fig. 51 the door trip is screwed over the door so that the lowest arm A is struck by the door. When the door is opened, in the direction of the arrow, the arm A is thrust forwards, and in its turn moves the contact arm C , completing the bell and battery circuit. But when the door is being closed, A swinging in the reverse direction does not move C and no alarm is given....
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Miscellaneous Alarms.
Miscellaneous Alarms.
The Applegate electrical matting is composed of wooden slats with springs so arranged that the weight of any person stepping on it will close a circuit and ring a bell. It is intended to be put under the ordinary door mat or under stair and room carpeting. The Yale lock switch is a Yale lock and switch combined. Upon any key but the right one being inserted, a circuit is closed and an alarm bell is rung....
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The Annunciator.
The Annunciator.
The mechanism of an annunciator consists of electromagnets which allow shutters to drop or needles to move on the circuits being closed. A bell is also rung in most cases to call attention to the annunciator. The number of the circuit is marked on the shutter, or near the needle, either shutter or needle being replaced by a reset device, which may be mechanical or electrical. Annunciator drops are made in a variety of forms. Fig. 52 illustrates the principle underlying nearly all of them. When c
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Wiring up an Annunciator.
Wiring up an Annunciator.
A diagram of the connections for an annunciator with a separate bell is given in Fig. 57 . Where the bell is contained in the case a terminal will be generally found for connection. The figure shows a wire running from the battery to one side of each push button. This is the common return, or battery wire, and saves installing two wires from each push. It should be larger, however, than the rest of the wires, generally about No. 16 B. & S. All the wires for an annunciator should be run b
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Three Wire Return Call System.
Three Wire Return Call System.
A three wire return call annunciator system is shown in Fig. 60 . There are two battery wires installed, from which taps are taken off and led to each room or push button. Three way or return call push buttons are used as shown at points marked B . In the diagram, the bells are marked A , the drops in the annunciator D , the annunciator bell C and the return call buttons in the annunciator E . The batteries are as shown at F . The heavy black outline encloses the annunciator mechanism and connec
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Installing Elevator Annunciators.
Installing Elevator Annunciators.
The installing of electric bells and annunciators in elevators does not present any special problems, although the apparatus used must be selected with a view to its being suitable to withstand the shocks incident to elevator service. In general the wires leading from the push buttons on the different floors to the bell or annunciator in the elevator, are flexible and made up into a cable. One end of this cable is attached to the underside of the elevator car, the other end being fixed usually t
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Burglar Alarm Annunciators.
Burglar Alarm Annunciators.
Although almost any annunciator may be used for open circuit burglar alarm work, they usually do not contain certain devices which are desirable in burglar alarm work. In Fig. 62 is shown a diagram of a burglar alarm annunciator, the view being schematic of the back board. The references are as follows: A is the main alarm bell situated wherever desired and connected to the binding posts BB . The battery connection leading directly to the battery K is marked C and that leading to the contact spr
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Clock Alarm Circuit.
Clock Alarm Circuit.
A diagram of the wiring and connections on the back board of all clock alarms is illustrated in Fig. 63 . This diagram embodies the principles of the last described circuit, but includes the circuit of a clock-operated alarm....
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Bells for High Voltages.
Bells for High Voltages.
The use of electric bells on lighting circuits is becoming quite general, as it obviates the necessity of using batteries, and thereby simplifies both installation and maintenance. There is no fundamental objection to operating make and break bells on electric light circuits. Providing the voltage and amperage are the same, there is little difference between the current from a direct-current dynamo and that from a battery. But owing to the higher voltages of the lighting circuit over that genera
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Bell-ringing Transformers.
Bell-ringing Transformers.
The best system for operating bells and annunciators from alternating current circuits is undoubtedly that employing small specially constructed transformers to reduce the voltage. These transformers are being used universally for hotel and office work where alternating current is available. They are simple, being merely one or more coils of well insulated wire wound on soft iron cores and having connections for both the lighting circuit and the bell circuit. As a general rule the coils are divi
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Combination Circuits.
Combination Circuits.
Circuits intended primarily for electric bells or annunciators in houses and apartments may often be also made to serve for other electrical devices such as door openers, house telephones, etc. This subsidiary apparatus may be installed with a little additional wiring or perhaps will not need any other wires, as when both the devices are not used at once. Electrical door openers are great conveniences and are practically indispensable where the outside door is on another level to the location of
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Fire Alarm Circuits.
Fire Alarm Circuits.
A fire alarm circuit suitable for factories, private plants or groups of buildings is shown in Fig. 68 . It is a series system, with closed circuit, the gongs sounding whenever the circuit is opened whether by the contact breaker in the boxes or by the accidental breaking of a wire. This insures that it remains in good working order, as when any part of the circuit is opened, a warning tap is sounded on every bell or gong. The boxes have contact breakers which send a separate number of impulses
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Interior Fire Alarm System.
Interior Fire Alarm System.
Another system suitable more particularly for indoor operation is illustrated in Fig. 69 . Here the alarm is given by breaking the glass front of an alarm box and releasing or pressing an electrical contact. The box sounded indicates by causing a drop to fall on an annunciator and at the same time rings an alarm bell. The latter are generally provided with constant ring attachments, which keep the bell sounding until shut off. The annunciator shown in the diagram has switches for controlling eac
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Fire Alarm System for Considerable Areas.
Fire Alarm System for Considerable Areas.
Where the area is more extensive and the number of stations considerable, the system illustrated in Fig. 70 is very suitable. It consists of the requisite number of break-glass boxes, bells and a more elaborate annunciator system. In general details it resembles the last system, but uses a relay to send out the current for ringing the alarm bells. When a box operates, the current impulses sent on the line act on the relay instead of directly on the bells. Each stroke of the relay closes a local
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Dubelle’s Famous Formulas.
Dubelle’s Famous Formulas.
By G. H. DUBELLE. A practical Receipt Book for Druggists, Chemists, Confectioners and Venders of Soda Water. SYNOPSIS OF CONTENTS. Introduction. —Notes on natural fruit juices and improved methods for their preparation. Selecting the fruit. Washing and pressing the fruit. Treating the juice. Natural fruit syrups and mode of preparation. Simple or stock syrups. FORMULAS. Fruit Syrups. —Blackberry, black current, black raspberry, catawba, cherry, concord grape, cranberry, lime, peach, pineapple, p
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A PRACTICAL HANDBOOK ON THE Distillation of Alcohol FROM FARM PRODUCTS AND DE-NATURING ALCOHOL.
A PRACTICAL HANDBOOK ON THE Distillation of Alcohol FROM FARM PRODUCTS AND DE-NATURING ALCOHOL.
By F. B. WRIGHT. Including the Free Alcohol Law and its Amendment, the Government regulations therefore and a number of U. S. government authorized de-naturing formulas. In the preparation of this, the second edition, the author has followed his original plan of writing a plain practical handbook on the manufacture of alcohol and de-naturing for industrial purposes. This industry is bound to grow to enormous proportions as it has in Germany where over 100,000,000 gallons were manufactured last y
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