When loaded, the crane can
operate at the following speeds: bridge, 250 feet per minute; trolley,
100 feet per minute; main hoist, 12 feet per minute; and auxiliary
hoist, 28 feet per minute.
The power house is provided with an extensive tool equipment for a
repair and machine shop, which is located on the main gallery at the
northerly side of the operating room.
[Illustration: 5,000 K. W. ALTERNATOR--MAIN POWER HOUSE]
CHAPTER V
SYSTEM OF ELECTRICAL SUPPLY
[Sidenote: _Energy from
Engine Shaft
to Third Rail_]
The system of electrical supply chosen for the subway comprises
alternating current generation and distribution, and direct current
operation of car motors. Four years ago, when the engineering plans
were under consideration, the single-phase alternating current railway
motor was not even in an embryonic state, and notwithstanding the
marked progress recently made in its development, it can scarcely yet
be considered to have reached a stage that would warrant any
modifications in the plans adopted, even were such modifications
easily possible at the present time. The comparatively limited
headroom available in the subway prohibited the use of an overhead
system of conductors, and this limitation, in conjunction with the
obvious desirability of providing a system permitting interchangeable
operation with the lines of the Manhattan Railway system practically
excluded tri-phase traction systems and led directly to the adoption
of the third-rail direct current system.
Pages:
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117