Interborough Rapid Transit Company.

Interborough Rapid Transit: the New York subway; its construction and equipment online

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proximately 10,000 electrical horse




ITCHES MAIN POWER STATION



INTERBOROUGH



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TRANSIT PAGE 95



T H E S L ! B \V A Y



tically as large a unit of the direct-connected type as can be constructed by the engine builders unless more
than two bearings be used an alternative deemed inadvisable by the engineers of the company. The
adoption of a smaller unit would be less economical of floor space and would tend to produce extreme
complication in so large an installation, and, in view of the rapid changes in load which in urban railway
service of this character occur in the morning and again late in the afternoon, would be extremely difficult to
operate.

The experience ot the Manhattan plant has shown, as was anticipated in the installation of less output
than this, the alternators must be put in service at intervals of twenty minutes to meet the load upon the
station while it is rising to the maximum attained during rush hours.

After careful consideration of the possible use of steam turbines as prime-movers to drive the alternators,
the company's engineers decided in favor of reciprocating engines. This decision was made three years ago
and, while the steam turbine since that time has made material progress, those responsible for the decision are
confirmed in their opinion that it was wise.

The alternators closely resemble those installed by the Manhattan Railway Company (now the Man-
hattan division of the Interborough Rapid Transit Company) in its plant on the East River, between 74th Street
and 75th Street. They differ, however, in having the stationary armature divided into seven castings instead
of six, and in respect to details ot the armature winding. They are three-phase machines, delivering twenty-
five cycle alternating currents at an effective potential ot 11,000 volts. They are 42 feet in height, the




PART OF EL'S BAR



MAIN POWER STATION



PAGE g^INTERBOROUGH RAPID TRANSIT



THE S U B \V A Y




diameter of the revolving part is 32 feet, its weight, 332,000 pounds, and the aggregate weight of the
machine, 889,000 pounds. The design of the engine dynamo unit eliminates the auxiliary fly wheel
generally used in the construction ot large direct-connected units prior to the erection of the Manhattan
plant, the weight and dimensions of the revolving alternator field being such with reference to the turning
moment ot the engine as to secure close uniformity of rotation, while at the same time this construction
results in narrowing the engine and reducing the engine shafts between bearings.

Construction of the revolving parts of the al-
ternators is such as to secure very great strength and
consequent ability to resist the tendency to burst
and fly apart in case of temporary abnormal speed
through accident of any kind. The hub of the
revolving field is of cast steel, and the rim is carried
not by the usual spokes but by two wedges ot rolled
steel. The construction of the revolving field is
illustrated on pages 91 and 92. The angular
velocity of the revolving field is remarkably uni-

turm. This result is due primarily to the fact

; , (

DUCT LINE ACROSS 58TH STREET

engine is tar more uniform than is the case, 33 DUCTS




INTER BOROUGH



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TRANSIT PAGE 97



THE SUBWAY



T R U C T I O



EQUIPMENT




1'2 tender Panels



1 - Grogp Panel




|| O Q ^(S)fQ

|'j O"ofcpro

l|Oc<rjj"

l-evU.-r Swilches (ir<-ii|> S llcbcs




MAIX COXTliOLLIXG BOA1JD IX POAVEK STATIOX

for example, with an ordinary two-cylinder engine. The large fly-wheel capacity of the rotating element of
the machine also contributes materially to secure uniformity of rotation.

I he alternators have forty field poles and operates at seventy-five revolutions per minute. The field
magnets constitute the periphery <>f the revolving field, the poles and rim of the field being built up by steel
plates which are dovetailed to the driving spider. The heavy steel end plates are bolted together, the lami-
nations breaking joints in the middle ot the pole. The field coils are secured by copper wedges, which are




PAGE 98



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TRANSIT



T H K S T B \V \ V




DUCTS I XDEK PASSICXOKK STATIOX PLATFORM
G4Dl'< TS



subjected to shearing strains
only. In the body of the
poles, at intervals of ap-
proximately three inches,
ventilating spaces are pro-
vided, these spaces register-
ing with corresponding air
ducts in the external arma-
ture. The field winding
consists of copper strap on
edge, one layer deep, with
fibrous material cemented
in place between turns, the
edges ot the strap being
exposed.

T h e armature is sta-
tionary and exterior to the

field. It consists of a laminated ruin with slots on its inner surface and supported by a massive external cast-
iron frame. The armature, as has been noted, comprises seven segments, the topmost segment being in the
form of a small keystone. I his may be removed readily, affording access to any field coil, which in this
way may be easily removed and replaced. The armature winding consists of U-shaped copper bars in par-
tially closed slots. There are four bars per slot and three slots per phase per pole. The bars in any slot
may be removed from the armature without removing the frame. The alternators, ot course, are separately
excited, the potential of the exciting current used being 250 volts.

As regards regulation, the manufacturer's guarantee is that at 100 per cent, power factor it full rated
load be thrown off" the e. m. f. will rise 6 per

cent, with constant speed and constant ex- _^1P

citation. The guarantee as to efficiency is as
follows : On non-inductive load, the alter-
nators will have an efficiency ot not less than
90.5 per cent, at one-quarter load; 94.75 per
cent, at one-halt load; 90.25 per cent, at
three-quarters load ; 97 per cent, at full load,
and 9~.2<; per cent, at one and one-quarter
load. These figures refer, of course, to elec-
trical efficiency, and do not include windage
and bearing friction. The machines are tie-
signed to operate under their rated full load
with rise of temperature not exceeding _55
degrees C. after twenty-tour hours.

"* W " THREE-CONDUCTOR NO. OOO CABLE

YOR I I, OOO VOLT DISTRIBUTION



_"




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99



T H E S U B W A Y



To supply exciting current for the fields of the alternators and to operate motors driving auxiliary ap-
paratus, five 250-kilowatt direct current dynamos are provided. These deliver their current at a potential of
250 volts. Two of them are driven by 400 horse-power engines of the marine type, to which they are
direct-connected, while the remaining three units are direct-connected to 365 horse-power tri-phase induction
motors operating at 400 volts. A storage battery capable of furnishing 3,000 amperes for one hour is used
in co-operation with the dynamos provided to excite the alternators. The five direct-current dynamos are
connected to the organization of switching apparatus in such a way that each unit may be connected at will
either to the exciting circuits or to the circuits through which auxiliary motors are supplied.

The alternators for which the new I nterborough Power House are designed will deliver to the bus bars

100,000 electrical horse power. The current deliv-
ered by these alternators reverses its direction fifty
times per second and in connecting dynamos just
coming into service with those already in operation
the allowable difference in phase relation at the
instant the circuit is completed is, of course, but a
fraction of the fiftieth of a second. Where the power
to be controlled is so great, the potential so high, and
the speed requirements in respect to synchronous
operation so exacting, it is obvious that the perfec-
tion of control attained in some of our modern
plants is not their least characteristic.

The switch used for the 11,000 volt circuits
is so constructed that the circuits are made and
broken under oil, the switch being electrically oper-
ated. Two complete and independent sets of bus
bars are used, and the connections are such that each
alternator and each feeder may be connected to either
of these sets of bus bars at the will of the operator.
From alternators to bus bars the current passes, first,
through the alternator switch, and then alternatively
through one or the other of two selector switches
which are connected, respectively, to the two sets
of bus bars.

Provision is made for an ultimate total of twelve
sub-stations, to each of which as many as eight feeders
may be installed if the development of the company's
business should require that number. But eight sub-
stations are required at present, and to some of these
not more than three feeders each are necessary.



INSIDE WALL OF TUNNEL
SHOWING O4 DUCTS




__ 'J/)/>t/ 1'iltlt S



'



The aggregate number of feeders installed for the



PAGE too INTERBOROUGH



RAPID



TRANSIT



THE SUBWAY



feeders are arranged in groups, each group
being supplied from a set of auxiliary luis
liars, which in turn receives its supply from
one or the other of the two sets of main hus
bars ; means for selection being provided as
in the case of the alternator circuits by a pair
of selector switches, in this case designated
as group switches. The diagram on page 93
illustrates the essential features of the organi-
zation and connections of the i i ,000 volt
circuits in the power house.

Any and every switch can be opened or
closed at will by the operator standing at the



initial operation of the subway
system is thirty-four.

Each feeder circuit is pro-
vided \\ith a type H-oil switch
arranged to be open and closed
at will by the operator, and also
to open automatically in the
case of abnormal flow of cur-
rent through the feeder. The




tANHOLES IN SIDE WALL OK SUBWAY




CONVERTER FLOOK PLAN

SUB -STATION" NO. 14



PAGE 102 INTERBOROUGH



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TRANSIT



THE SUB \V A Y



control board described. The alternator
switches are provided also with automatic over-
load and reversed current relays, and the feeder
switches, as above mentioned, are provided
with automatic overload relays. These overload
relays have a time attachment which can be set
to open the switch at the expiration ot a pre-
determined time ranging trom .3 of a second
to 5 seconds.

The type H-oil switch is operated by an
electric motor through the intervention of a
mechanism comprising powerful springs which
open and close the switch with great speed.
This switch when opened introduces in each
of the three sides of the circuit two breaks
which are in series with each other. Each
side of the circuit is separated from the others
CROSS SECTION SUB -STATION NO. 14 by ; ts l ocation in an enclosed compartment, the

walls of which are brick and soapstone. The general construction of the switch is illustrated by the photograph
on page 94.





NTERIOR OF SUB-STATION NO. II



PAGE 104 INTERBOROUGH



R A P I D



T R A N S I T



THE SUB W A Y



Like all current-carrying parts of
the switches, the bus bars are enclosed
in separate compartments. These are
constructed ot brick, small doors for
inspection and maintenance being pro-
vided opposite all points where the bus
bars are supported upon insulators. The
photographs on pages 95 and 9.6 are views
ot a part of the bus bar and switch com-
partments.

The oil switches and group bus
bars are located upon the main floor and
extend along the <;<jth Street wall ot the





TWO GROUPS OF TRANSFORMERS



engine room a distance of about 600 feet. The main
bus bars are arranged in two lines of brick compart-
ments, which are placed below the engine room floor.
These bus bars are arranged vertically and are placed
directly beneath the rows of oil switches located upon
the main floor of the powerhouse. Above these rows
of oil switches and the group bus bars, galleries
are constructed which extend the entire length
of the power house, and upon the first ot these
galleries at a point opposite the middle of the
power house are located the control board and
instrument board, by means of which the oper-
ator in charge regulates and directs the entire
output ot the plant, maintaining a supply ot
power at all times adequate to the demands
ot the transportation service.



1 N T E R B O R O U C, H



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THE SUB W A V




,5OO K. W. RUTARY CUNVtKILK



TRANSIT PAGE I0 5

N II K 1,1 1' I I- M E N 1

The control board is shown ^fic Control
in the photograph on page 97.
Every alternator switch, every
selector switch, every uroup
switch, and every tecder switch
upon the main floor is here rep-
resented by a small switch. The
small switch is connected into a
control circuit which receives its
supply ot energy at 110 volts
trom a small motor generator
set and storage battery. I lie
motors which actuate the large
oil switches upon the mam floor
are driven by tins i 10 volt con-
trol current, and thus in the



hands of the operator the control switches make or break the relatively teeble control currents, which, in
turn, close or open the switches in the mam power circuits. The control suitches are systematically assem-
bled upon the control bench board in conjunction with dummy bus bars and other apparent (but not real)
metallic connections, the whole constituting at all times a correct diagram ot the existing connections ot the
main power circuits. Kvery time the operator changes a connection by opening or closing one ot the main
switches, he necessarily changes his diagram so that it represents the new conditions established by opening
or closing the mam switch. In connection with each control switch two small bull's-eye lamps are used, one
red, to indicate that the corresponding main switch is closed, the other green, to indicate that it is open. 1 hese
lamps are lighted when
the moving part ot the
main switch reaches ap-
proximately the end of
its travel. If for any
reason, therefore, the
movement of the con-
trol switch should tall
to actuate the main
switch, the indicator
lamp will not be
lighted.

The control board
is divided into two
parts o n e f o r t h e
connections of the




PAGE io6iNTERBOROUGH RAPID TRANSIT



THE SUBWAY



The
Instrument

Board



alternators to the bus bars and the other tor the connection of feeders to bus bars. The drawing on
page 97 shows in plain view the essential features of the control boards.

A front view of the Instrument Board is shown on page 97. This board contains all indicating instru-
ments for alternators and teeders. It also carries standardizing instruments and a clock. In the illustration
the alternator panels are shown at the left and the feeder panels at the right. For the alternator panels, instru-
ments of the vertical edgewise type are used. Each vertical row comprises the measuring instruments for an
alternator. Beginning at the top and enumerating them in order these instruments are : Three ammeters, one
for each phase, a volumeter, an indicating wattmeter, a power factor indicator and a field ammeter. I he
round dial instrument shown at the bottom of each row of instruments is a three-phase recording wattmeter.

A panel located near the center of the board between alternator panels and feeder panels carries standard
instruments used for convenient calibration of the alternator and feeder instruments. Provision is made on
the back of the board for convenient connection of the standard instruments in series with the instruments to
be compared. The panel which carries the standard instruments also carries ammeters used to measure cur-
rent to auxiliary circuits in the power house.

For the feeder board, instruments of the round dial pattern are used, and for each feeder a single instru-
ment is provided, viz., an ammeter. Each vertical row comprises the ammeters belonging to the teeders
which supply a given sub-station, and from left to right these are in order sub-stations Nos. 11, 12, ij, 14,
i <;, i 6, 17, and 18 ; blank spaces are left for four additional sub-stations. Each horizontal row comprises the
ammeter belonging to teeders which are supplied through a given group switch.

This arrangement in vertical and hor-
izontal lines, indicating respectively feeders
to given sub-stations and feeders connected
to the several group switches, is intended
to facilitate the work of the oper-
ator. A glance down a vertical
row without stopping to reach the
scales of the instruments will tell
him whether the teeders are divid-
ing with approximate equality the
load to a given sub-station. Feed-
ers to different substations usually
carry different loads and, generally
speaking, a glance along a hori-
zontal row will convey no inform-
ation of especial importance. It,
however, for any reason the oper-
ator should desire to know the
approximate aggregate load upon a group
of teeders this svstematic arrangement of

. O

the instruments is of use.

SWITCHBOARD KOR ALTERNATING CURRENT BLOCK SIGNAL CIRCUITS IN SUB-STATION




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THE SUB W A Y




The location and arrangement of
ducts along the line of the subway arc-
illustrated in photographs on pages 98
and 99, which show respectively a sec-
tion of ducts on one side of the sub-
way, between passenger stations, and a
section of ducts and one side of the
subway, beneath the platform of a
passenger station. From City Hall
to g6th Street (except through the
Park Avenue Tunnel) sixty-tour ducts
are provided on each side ot the sub-
way. North of 96th Street sixty-four
ducts are provided for the West-side
lines and an equal number for the
East-side lines. Between passenger
stations these ducts help to form the
side walls of the subway, and are ar-
ranged thirty-two ducts high and two
ducts wide. Beneath the platform of
passenger stations the arrangement
is somewhat varied because of local



From alternators to alternator switches the
11,000 volt alternating currents are conveyed
through single conductor cables, insulated by oil
cambric, the thickness of the wall being I -/-M of
an inch. These conductors are installed in vitri-
fied clay ducts. From dynamo switches to bus
bars and from bus bars to group and feeder
switches, vulcanized rubber insulation contain-
ing 30 per cent, pure Para rubber is employed.
The thickness ot insulating wall is ,'s-2 of an inch
and the conductors are supported upon porcelain
insulators.

From the power house to the subway at 5 8th
Street and Broadway two lines of conduit, each
comprising thirty-two ducts, have been constructed.
These conduits are located on opposite sides of
the street. The arrangement of ducts is 8x4, as
shown in the section on page 96.



,



Alternating
Current
Distribution
to Sub-Stations
Power House
Ducts and
Cables



Conduit
System for
Distribution







EXTERIOR OF SUB-STATION NO. I I



PAGE io8 IN TERBOROUGH RAPID TRANSIT



THE SUBWAY



obstructions, such as pipes, sewers, etc., ot which it was necessary to take account in the construction of
the stations. The plan shown on page 98, however, is typical.

The necessity of passing the cables from the 32x2 arrangement of ducts along the side of the tunnel
to 8 x 8 and 16x4 arrangements of ducts beneath the passenger platforms involves serious difficulties in the
proper support and protection of cables in manholes at the ends of the station platforms. In order to
minimize the risk of interruption of service due to possible damage to a considerable number of cables in one
of these manholes, resulting from short circuit in a single cable, all cables except at the joints are covered with
two layers of asbestos aggregating a full '^.-inch in thickness. This asbestos is specially prepared and is
applied by wrapping the cable with two strips each 3 inches in width, the outer strip covering the line of
junction between adjacent spirals of the inner strip, the whole when in place being impregnated with a solution
of silicate of soda. The joints themselves are covered with two layers of asbestos held in place by steel tape
applied spirally. To distribute the strains upon the cables in manholes, radical supports of various curvatures,
and made of malleable cast iron, are used. The photograph on page 100 illustrates the arrangement of
cables in one of these manholes.




n bUB-Sl A TION Ml I I



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THE SUBWAY



In order to further diminish the risk of interruption of the service due to failure of power supply, each
sub-station south of 96th Street receives its alternating current from the power house through cables carried
on opposite sides of the subway. To protect the lead sheaths of the cables against damage by electrolysis,
rubber insulating pieces ^j- of an inch in thickness are placed between the sheaths and the iron bracket sup-
ports in the manholes.

The cables used for conveying energy from the power house to the several sub-stations aggregate
approximately 150 miles in length. The cable used for this purpose comprises three stranded copper
conductors each of which contains nineteen wires, and the diameter of the stranded conductor thus formed
is % of an inch. Paper insulation is employed and the triple cable is enclosed in a lead sheath %-t of an
inch thick. Each conductor is separated from its neighbors and from the lead sheath by insulation of treated
paper vie of an inch in thickness. The outside diameter of the cables is 2j^ inches, and the weight 8^
pounds per lineal foot. In the factories the cable as manufactured was cut into lengths corresponding to the
distance between manholes, and each length subjected to severe tests including application to the insulation
of an alternating current potential of 30,000 volts for a period of thirty minutes. These cables were
installed under the supervision of the Interborough Company's engineers, and after jointing, each complete
cable from power house to sub-station was tested by applying an alternating potential of 30,000 volts for
thirty minutes between each conductor and its neighbors, and between each conductor and the lead sheath.
The photographs on page 98 illustrates the construction of this cable.

The tri-phase alternating current generated at the power house is conveyed through the high potential
cable system to eight sub-stations containing the necessary transforming and converting machinery. These
sub-stations are designed and located as follows :



Cable

Conveying

Energy

from

Power House to

Sub-Stations



Sub-Station






pg




?


_t






r




1 -


I i




1 - n



Track Returns




DIAGRAMS OF
DIRECT CURRENT FEEDER

AND
RETURN CIRCUITS



PAGE no INTERBOROUGH



RAPID



TRANSIT



THE SUBWAY ITS




and a sub-station site comprising two
tion of a maximum of eight
1,500 kilowatts converters with
necessary transformers, switch-
board and other auxiliary appa-
ratus. In designing the sub-
stations, a type of building with
a central air-well was selected.
The typical organization of ap-
paratus is illustrated in the ground
plan and vertical section on
pages 101, 1 02 and 103 and pro-
vides, as shown, for two lines of
converters, the three transformers



Sub-station No. 11 29-33
City Hall Place.

Sub-station No. 12 108-
1 10 East 1 9th Street.

Sub-station No. 13 - 5~
227 West 53d Street.

Sub-station No. 14 264-
266 West 96th Street.

Sub-station No. 15 606-
608 West I43d Street.

Sub-station No. 16 73~77
West I32d Street.

Sub-station No. 17 Hill-
side Avenue, 301 feet West of
Eleventh Avenue.

Sub-station No. 18 South
side of Fox Street (Simpson
Street), 60 feet north of West-
chester Avenue.

The converter unit selected
to receive the alternating cur-
rent and deliver direct current
to the track, etc., has an output
of 1,500 kilowatts with ability
to carry 50 per cent, overload
for three hours. The average
area of a city lot is 25 x 100 feet,
adjacent lots of this approximate size permits the installa-



SWITCH CONNECTING FF-HI'EK




CONTACT RAIL JOINT WITH FISH PLATE



INTERBOROUGH



RAPID



TRANSIT PAGE



THE SUBWAY




CONTACT KAIL BANDS



which supply each converter be-
ing located between it and the
adjacent side wall. The switch-
board is located at the rear of
the station. The central shah
affords excellent light and ven-
tilation for the operating room.
The steel work of the sub-
stations is designed with a view
to the addition of two storage
battery floors, should it be de-
cided at some future time that
the addition of such an auxiliary
is advisable.


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Online LibraryInterborough Rapid Transit CompanyInterborough Rapid Transit: the New York subway; its construction and equipment → online text (page 8 of 13)