Chapter I: Preface

So rapidly has the use of electric bells and similiar signalling appliances extended, in modern houses, offices, hotels, lifts, and ships, that every bell-fitter must have felt the need of accurate knowledge of the manner in which these instruments act and are made.

In the following pages the author has attempted to supply this need, by giving full details as to the construction of batteries, bells, pushes, detectors, etc., the mode of wiring, testing, connecting up, localizing faults, and, in point of fact, by directing careful attention to every case that can present itself to the electric-bell fitter.

CARSHALTON, SURREY,
_November, 1888_.

CONTENTS.

CHAP. PAGE

I. PRELIMINARY CONSIDERATIONS 1

II. ON THE CHOICE OF BATTERIES FOR ELECTRIC BELL WORK 18

III. ON ELECTRIC BELLS AND OTHER SIGNALLING APPLIANCES 59

IV. ON CONTACTS, PUSHES, SWITCHES, KEYS, ALARMS, AND RELAYS 109

V. ON WIRING, CONNECTING UP, AND LOCALISING FAULTS 144

LIST OF ILLUSTRATIONS.

FIG. PAGE

1. Direction of current in cell 9

2. " " out of cell 10

3. Bar and horse-shoe magnets 14

4. The Dynamo 16

5. " Smee cell 28

6. " Daniell cell 30

7. " Gravity cell 32

8. " Leclanch['e] cell and parts 34

9. " Agglomerate cell 40

10. " Judson cell 42

11. " Battery in box 43

12. " Gent cell 44

13. " Bichromate cell 48

14. " Fuller cell 50

15. " Cells coupled in series 54

16. " " " Parallel 57

17. Outline of electric bell 61

18. Frame of bell 62

19. E-shaped frame 63

20. Electro-magnet, old form 64

20A. " " modern form 65

21. Magnet frame 66

21A. Winder 72

22. Mode of joining electromagnet wires 73

23. Armature spring 74

24. " " Another form 74

25. Platinum tipped screw 75

26. " " spring 76

27. Binding screws 77

28. Bell or gong 78

29. Pillar and nuts 78

30. Washers 78

31. Trembling bell 81

32. Bell action enclosed in case 88

33. Ordinary trembling bells 90

34. Single stroke bell 91

35. Continuous ring bell 94

36. Release action 95

37. Continuous ringing with relay 96

38. Continuous ringing action with indicator 97

39. Relay and detent lever for indicator 97

40. Callow's attachment 99

40A. Thorpe's arrangement 101

41. Jensen bell, _section_ 102

42. " " _exterior_ 104

43A. Circular bell 106

43B. Mining bell 106

44. Electric trumpet (Binswanger's) 107

45. Various forms of pushes 110

46. Pressel 111

47. Pull 112

48. Bedroom pull 113

49A. " " Another form 114

49B. Floor contact, ball form 114

50. Burglar alarm 115

51. " " Another form 115

52. Floor contact 115

53. Door contact 116

54. Sash contact 117

55. Shop door contact 117

56A. Closed circuit system, _single_ 119

56B. Closed circuit system, _double_ 119

57. Modified gravity, Daniell 120

58. Contact for closed circuit 121

59. Thermometer alarm 122

60. Fire alarm 123

61A. " " Another form 123

61B. " " " " in action 123

62. Binswanger's "watch alarm" contact 125

63. Watchman's electric tell-tale clock 126

64. Lever switch, _two-way_ 128

65. Morse key, _double contact_ 133

66. Relay 134

67. Indicator, drop 137

68. " Semaphore 138

69. " Fall back 139

70. " Pendulum 140

71. " Coupled up 142

72. " Gent's tripolar 143

73. Soldering iron and wires 148

74. Push, interior of 151

75. Bell, battery and push 159

76. " " And earth return 160

77. " and two pushes 161

78. " two pushes and one pull 161

79. Two bells in parallel 162

80. " " Another mode 162

81. " " with two-way switch 163

82. Series coupler 163

83. Bell with local battery and relay 164

84. Continuous ringing bell with wire return 165

85. Bells with Morse keys for signalling 165

86. Bells with double contact pushes for signalling 166

87. Bells with double contact with one battery only 167

88. Two-way signalling with one battery only 168

89. Complete installation of bells, batteries, pushes, etc. 169

90. Mode of getting out plan or design 170

91. Lift fitted with bells 173

92. Magneto bell: generator 174

93. " " Receiver 175

94. " " Combined 176

95. Detector or galvanometer 176

ELECTRIC BELLS.