[Illustration: FIG. 5.]
This type of machine is entirely theoretical. In the apparatus used
for Prof. Pfaundler's experiments in 1870, the armature revolved with
the solenoid. The core and armature were of soft iron, and the core
was arranged in a manner analogous to the preceding, and remained in
place under the action of its weight, and the shell, forming a
complete circle, revolved with poles fixed in space.
Practically, the machine that we have just described would prove
inconvenient to realize, and would present serious inconveniences. In
the first place, it seems to us quite difficult to transmit the motion
of the solenoid to the axle, supposing the former to revolve within
the armature. In the second place, considerable friction would surely
occur between the spirals and core, and the axle, being submitted to a
lateral stress, would be placed in a poor condition for work. It is
even allowable to doubt whether such a type could be practically got
up. At all events, no trial has as yet been made of it.
Compared with the Gramme machine, from an absolutely theoretical point
of view, the Pfaundler apparatus presents undoubted advantages. A
theoretically perfect dynamo electric machine would be one in which
there was a complete reciprocity between the magnetizing action of the
current and the inductive action of the magnetic field. Now, such is
not the case in the Gramme machine.
Pages:
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91