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"The New York Municipal Car -- Motors, Control, Conduit and Collectors " (1915)

ELECTRIC RAILWAY JOURNAL · Vol. 45, No. 11 · March 13, 1915 · pp 496-503.

The New York Municipal Car -- Motors, Control, Conduit and Collectors

NEW YORK MUNICIPAL CAR -- THE FIRST EIGHT-CAR TRAIN READY FOR A TRIAL RUN ON THE NEW SEA BEACH LINE.

Tapped-Field Motors Give Economical Operation in Both Local and Express Service -- The Control Ties in with the Auxiliary Circuits and Its Switches Are Placed in One Box to Obtain Lowest Weight and Simplest Inspection -- Conduit Runs Have Been Reduced by Eliminating Separate Conduits for Each of the Wires in the Main Circuits.

The motors, the control and the accessories of both on the New York Municipal car embody the same principle of progress that characterizes the features of design and equipment which have been previously described in these columns. (See New York Municipal Car articles on "Design," "Body" and "Trucks, Brake Rigging and Draft Gear," June 6, June 13, and Dec. 26, 1914, respectively.) As the following paragraphs will show, the New York Municipal Railway Corporation has not only taken advantage of the latest advances in the art but it has also set up new standards and devised new practices which will accrue to the benefit of other electric railway operators.

Character of Forthcoming Service

To appreciate the reason for electing to use the tap-field motor in the forthcoming service it is well to point out that three distinct services -- local, express and a combination or these two -- are contemplated. For purely local runs the schedule speed will be 15 m.p.h. with an average station stop of 20 seconds, and for purely express service the speed will be 25 m.p.h. with an average stop of 30 seconds.

On a typical local run like that of Fifty-ninth Street, New York, to Coney Island, by way of the Manhattan Bridge and Brighton Beach line, the shortest distance between stations will be 1100 ft., the longest 6220 ft., exclusive of the Manhattan Bridge, and the average 2430 ft. The length of this run will be 68,090 ft. plus the 10,560 ft. of the Manhattan Bridge.

On a typical express run like that from Forty-eighth Street, New York, to Sheepshead Bay, the shortest distance between stations will be 3930 ft., the longest, 9870 ft. and the average 7230 ft. The length of this run will be 43,380 ft.

On a typical combined express and local run like that from Forty-eighth Street, New York, to Coney Island via a 7000-ft. tunnel and the Brighton Beach line the shortest distance between stations will be 1263 ft., the longest, 9870 ft. and the average 4573 ft. The length of the run will be 82,327 ft. In general the local runs will be longer but the express runs shorter than on the present rapid transit lines of New York.

It was obvious that the tap-field motor was ideal for running conditions of the character described, inasmuch as such a motor could b6 run on full field in local service and on tapped field in express service. Self-ventilation was also desirable for the motor because the limiting weight per driving axle made it essential to combine greatest output with least weight. Besides this, the motor equipments will be kept in almost continuous service, as some of them will have only three minutes lay-over at terminals during continuous working periods of eighteen hours. Local trains will consist of two to five cars each and express trains of two to eight cars each.

The Motor

The motor selected for the first 100 cars (two per car) is the GE-248-A commutating pole type with fan assembled on the pinion end of the armature head. The frames are also constructed with openings in the covers. The motor weight, including the gear, pinion and gear case, is 5975 lb. The motor, under the A. I. E. E. standards, has an hourly rating of 160 hp at 600 volts.

This motor must operate over a voltage range of 450 to 750 volts, and its continuous ratings up to 600 volts are as follows: 140 amp at 300 volts, 147 amp at 400 volts, 154 amp at 500 volts and 157 amp at 600 volts, with a temperature rise in the windings not exceeding 75 deg. Cent, when all the covers are off. The general characteristics are shown in the curves on page 497. The ability of two of these motors to propel at an average of 550 volts a car weighing 113,000 lb. fully-loaded (200 passengers at 140 lb. each) is based on an assumed adhesion of 27.5 per cent between the driving wheels and rails, a curve resistance of 0.8 lb. per ton per degree of curvature and the following train resistance values:

The train resistance values were derived from tests made on near-by rapid transit lines.

The motor frame is of the box type, of cast steel fitted with a removable wearing plate of hardened steel on the motor suspension lug, and with cast bales for handling the completely assembled motor. A feature in the construction of the field coils is that their final coating of insulating compound has the unusually high melting point of 135 deg. Cent. Other features are that metal shields are fastened on the inner perimeter of the coils to prevent chafing on the pole pieces and that all the field coils are held in place against flat steel springs to prevent their movement in service.

The brush-holders, which are designed to permit 1-in. safe radial wear of the commutator, have shunts so constructed that they will not have any wearing action against the brush-holder casting. The brushes are placed in staggered relation, and their tension is adjustable between 3 lb. and 10 lb. The mica insulation between the commutator bars is cut 3/64 in. and extends 1/8 in. back of the commutator neck.

Lubrication has received special attention in the design of this motor. The bearing housings are supplied with separate oil gage wells and waste chambers. By removing the wooden plug of the external well and inserting a gaging ruler, the shopman can determine the quantity of oil in the gage well and if necessary can replenish the oil supply without exposing the lubricating packing to dust or needless handling. Oil deflectors are provided on the armature shaft to prevent the oil from working into the motor windings, onto the commutator or onto the brush-holders. The housings also contain grooves for conducting overflow oil to an auxiliary chamber on the outside of the motor. Wool waste is used in both the armature and axle bearings.

As the motors are of self-ventilating type special care was taken to prevent, as far as possible, dust from entering the bearings or wearing surfaces, dust guards being used at exposed points. Further, the axles are entirely inclosed in a shield to exclude dust from the inner ends of the bearings.

Safety straps are provided to prevent the fall of the lower half of the gear case should the nuts from the clamping bolts be lost. The gears and pinions are made of Grade F forged steel and have a ratio of 61:22. The gearing has teeth with a stub profile to meet the severe conditions anticipated.

Control

The control system is designated by its manufacturer, the Westinghouse Electric & Manufacturing Company, as Type 100 ABF. While it represents no great change in principle from a combination of the Westinghouse ABF and PK types of control, old elements have been combined in new ways and special duties have been added, as hereinafter detailed.

In this control the following features have been met for the first time:

First -- Combined design, which includes provision for the use of the storage battery furnished for emergency car lighting, common use of apparatus of the brake and electrical equipment, provision for signal and other functions in the control equipment and particular adaptability to the use of automatic electric couplers.

Second -- Selective acceleration, the current input being determined by the load.

Third -- Operation of sixteen motor cars from a common train line.

Fourth -- Use of a common eighteen-wire train line, including provision for auxiliary circuits.

Fifth -- The combination of all control apparatus in a single box to obtain the lowest weight and the simplest inspection.

The company considered also the use of control current taken direct from the 600-volt line, but it decided in favor of the 34-volt battery train line for the following reasons:

First -- In a 600-volt train line if the power is off the first car, none is available for operating the control for the rest of the train.

Second -- Since the brake actuating circuits should be independent of line voltage, it would be objectionable to have a 600-volt control circuit in a common train line with the low-voltage brake circuit.

Third -- The use of the battery permits the bucking of motors for emergency braking if the line power fails.

Fourth -- Low voltage secures greater freedom than line voltage from derangement of circuits such as those due to grounding and short-circuits.

Fifth -- A material saving in the cost of control power is secured.

Sixth -- Installation is simpler, with the elimination of switches, fuses and resistance elements.

Seventh -- There is greater certainty of reliable operation of a low voltage automatic electric coupler.

Eighth -- There are no high-voltage connections in the control apparatus above the floor of the car.

Ninth -- The storage battery required for emergency lighting and brake control can, without change, supply power for the control purposes.

Tenth -- Simpler design and installation of accessory apparatus, such as automatic electric couplers, is secured.

Eleventh -- The form and design of apparatus and contacts for handling the control circuit are simpler, with the elimination of burnouts on the master controllers and interlock fingers.

Battery and Train Line

In order to make the battery circuit available for signal lights, door circuit interlocks and to insure correct operation for a maximum possible train length of 1075 ft. the control battery had to be raised from the old standard of 14 volts to 34 volts. The cross-section of the train wires was also increased to avoid excessive drop, each conductor in the eighteen-conductor train line consisting of seven strands of No. 24 wire. The door signal circuit involves the use of train wires which extend in series to a distance equivalent to more than twice the train length.

All control circuits are energized from storage batteries on each car, all of which are permanently grounded on the negative side. The valve magnets require approximately 1.5 amp per car when the motors are in series, and 1.8 amp per car when the motors are in parallel. The storage battery has an estimated capacity of not less than 20 amp-hr. Charging current is available from the compressor during operation. Therefore the battery is mainly for emergency lighting, end and rear marker lights and for the operation of the electro-pneumatic brake circuit.

A total of eighteen wires is included in the train line, disposed as follows: Battery positive, one; brakes and speed control, five; local signal circuits between cars, one; starting signal and door interlock circuits, one; control circuits, seven; extra, three; total, eighteen.

The train line has three junction boxes, and includes wires for the operation of the magnet valves of the air-brake system, suitable outlets being provided for the circuits to the brake apparatus in the center of the car, and for the engineer's valves at each end. This includes provision for the automatic speed control device ind for synchronizing the compressor governors.

The air supply for the operation of the switching apparatus and the reverser of the control box is taken from the common air brake supply outside the reducing valve of the air-brake system.

With the reverse drum of the master controller in either the forward or the reverse position, the battery plus circuit is completed to the main drum of the controller, which in turn energizes the series wire, the progression wire and the multiple wire, on the first, second and third notches of the controller, respectively. On the first notch the main drum also completes the battery plus circuit for the operation of the reverser magnets to throw the reverse drum to the desired position. The interlocking on the main switches, reversers and the commutating switch is such that all operation must take place in the sequence indicated, and all main circuit apparatus is protected against injury due to the false operation of any part. It is necessary to complete the circuit for three wires at the master controller before power can be applied to the motors. These wires are the series wire, one or the other of the reversing wires, and the wire which is the return circuit for all magnet coils. With this provision and low-voltage control practically absolute insurance is given against any possibility of a faulty connection in the train line which might cause the operation of the train to be taken from the control of the motorman.

The Control Box

Another innovation in control equipment was promoted by the customer's specification that all of the usual under-car motive power apparatus, namely, unit switches, commutating switch, reverser, circuit-breaker and relays should be mounted in one box to effect a large saving in the length, weight and cost of conduit; and also to simplify inspection and to avoid shopping a car for several days when overhauling of the main control parts is required.

This control box includes the following parts: Two unit switches acting as circuit breakers; four unit switches for series paralleling the motor; one drum type reverser; one drum type commutating switch; one limit switch; one overload trip relay; one main circuit terminal board; one control circuit terminal board.

Unit construction is the basis of the switch design, and each switch, magnet, jacket and cylinder may be removed independently of the other parts of the apparatus.

The control is so designed that the upper compartment of the control box accommodates a main circuit junction box. By removing the motor leads and resistance leads from the terminal board and from a few of the studs the main assembly can be lowered from the car by loosening four supporting bolts, following which a new group may be substituted. It is estimated that within thirty minutes one man with the proper hoisting equipment can remove and replace the switch group.

The top frame of the switch group box is constructed to hang from the center sills of the car underframe by means of four lugs, no hanger straps being used. As shown in one of the under-car views, this box is mounted under the center of the car in such fashion that a man can walk around it on all sides. He is therefore able to remove with ease the doors which cover each compartment and then inspect the group and unit switches and the terminal board above them.

The general layout of the equipment in the control box is shown in part in an accompanying halftone and drawing, and further data on the location of individual parts are presented in the following paragraphs.

The current limit relay is placed alongside the reverser while the 34-volt terminal board is placed beneath the limit switch at the reverser end of the switch group. To this board is brought the conduit through which the control wires are run. All the necessary wiring connections for the motive power circuits were made at the factory, the only job left to the user being the attachment of ten motor leads, eight resistance leads, eight control wires, one ground lead and one trolley lead.

The overload trip relay is mounted next to the limit switch and consists of a plunger actuated by an arm which lifts at a predetermined current in the trip coil. The relay is calibrated in five steps at 100-amp intervals, starting with 450 amp which is approximately twice the one-hour rating of the motor. Contact disks on the plunger open the control circuits to all switches, and these circuits are re-established by unlatching the plunger by means of the reset coil, which may be energized by pressing a button in the top of the master controller after the main handle has been returned to the off position.

On the opposite end of the group of switches is mounted the PK head. The double air cylinder operating this drum is controlled by the unbalanced pressure system whereby the drum is moved from notch to notch under the control of the limit switch. Full pressure of air is maintained in both cylinders, and is intermittently exhausted from one side in order to allow the drum to move from notch to notch. After the drum has advanced, cutting out resistance and changing the field circuits to normal field in series, it returns to the first position after the closing of the J switch and advances again after the bridging and parallel connection has been made by the unit switches.

It will be noted that in normal operation no arcs can be broken on the commutating switch and drum, since the main switches are so arranged that no current is passing through the resistance fingers at a time when they are leaving the ground. However, a magnetic blow-out is provided to protect the field fingers in case a motor-lead becomes open-circuited. In passing from series to parallel, the J switch is closed, thus short-circuiting all resistance before the drum falls back to the first position, and in shutting off from any position on the master controller all the unit switches open before the drum starts to move backward.

For the specific manipulation of the main circuits, six steps are provided in series and four in multiple, with closed circuit or bridging transition between series and multiple to insure uniform acceleration. Each contact with this method carries the current for a single motor only. The two switches which are used as circuit breakers are isolated and have a separate vent for the expulsion of the arc to, atmosphere. They differ from the other unit switches only in the use of extended arc chutes, thus making all switch parts interchangeable. The remaining four unit switches establish the motor circuit connection to secure the series-parallel connection. In the operation of the overload trip all these switches open at the same time.

For the minor changes in the motor circuit the PK head is used. The PK contacts care simply for changes in resistance and for the changes in the field connections. They carry current for a single motor only. The adoption of this modified form of PK equipment eliminated eight control switches, made possible the use of a control box 4 ft. in length instead of 6 ft., and reduced the weight of the switch group to 850 lb.

The course of the circuit is as follows:

From the 500-amp position of the knife-switch connection to the current collectors, the circuit passes directly to the control box and to the overload trip. From the trip the circuit divides, passing through the two circuit-breaker switches, and then through each of the two motors with their starting resistance, and to the ground connection on the car body.

As shown on the main schematic diagram the circuit passes through LS-1 on the first notch; through the switching resistance; the No. 1 motor; the main starting resistance; through the JR switch; the resistance for the No. 2 motor, and through the No. 2 motor and the limit switch to ground. LS-2 closes for the second notch, and the remaining notches to full series are secured by cutting out the main starting resistance.

In passing from series to parallel, the bridging transition circuit is formed through the switches M-2, J and G. After the J switch is opened, the motors are in parallel with resistance, the resistance is then cut out step by step and the field connections changed to normal field in the same manner as was done in the series connection.

The line relay, which is placed on a switchboard located between the two center doors instead of being in the control box, is energized directly from the 600-volt circuit. Its contact disk is so connected in the control circuit that all unit switches open whenever power fails, permitting the control to advance in regular sequence when power is restored, without the master controller being returned to the off position. The relay is so adjusted that it will lift at approximately 350 volts and drop at approximately 150 volts. With this range, the relay has sufficient travel to insure positive action of the contacts and contact disk. The line relay also has auxiliary contacts to light the emergency lamps.

Master Controller

The master controller is equipped with the usual three notches for switching, series and multiple positions and with a separate reversing drum and the usual deadman's handle. The movement of the reverser handle to an operating position energizes the control-circuit supply, thereby eliminating an auxiliary cut-out switch. Inserted in the case at the right-hand side of the controller are an emergency cut-out switch for the 34-volt control circuit, a circuit-breaker reset button, a line relay cut-out button and marker-light switch button.

The deadman's handle on this controller acts by the application of battery current to the emergency train line wire. This application instantly energizes all emergency valves in the train upon the relaxation of the motorman's grasp at any position of the handle, whether the reverser is forward or reverse. By the same operation a special device completely cuts off power from the propulsion circuits.

The marker-light switch was added to the controller by the New York Municipal Railway. The signal lights which indicate that all doors have been closed are also installed in the master controller to avoid too many individual pieces of apparatus in the cab.

In addition to the usual contacts and fingers for the control circuit, the master controller has interlock contacts mounted on the reversing-drum shaft to provide for three auxiliary contacts. Two of these contacts are for signals and one is for tail-lights. These unusual features will be described in a later article in connection with the door signals, marker lights and train line coupler. The reverse drum acts as a switch to close the battery circuit to the control.

Still another new feature is that both polarities of the control circuits are broken at the controller. This is accomplished by running an extra train line wire for the negative side of the magnet coils. As no attempt has been made to ground the return circuit of the control, local grounds cannot create false circuits or cause false operation.

The line relay cut-out will permit the feeding up of the control when power is off the line and the bucking of the motors, as an emergency method of stopping the train should power be off the line and the air brake fail.

Selective Acceleration

In order to obtain the same rate of acceleration with all passenger loads from minima to maxima there is provided an extra winding on the limit switch which modifies the current input to the motors. The amount of current through this winding is controlled from a switch operated in connection with the empty and load brake mechanism. The adjustment of this mechanism corresponds directly to the deflection of the bolster springs under load.

Conduit

In the earlier installations of equipment separate conduits were used for each of the wires in the main circuits. In the present installation, however, multi-conductor cables are used. Consequently one large conduit pipe serves for each set of motor leads. Likewise, all resistance leads are formed into a cable and are carried from the switch group to the resistors through a single conduit with a Crouse-Hinds eight-conductor outlet. In order to reduce the weight of the conduit itself, material of the following character was used: For straight runs inside the car, circular steel tubing of 1/32-in. wall, inside diameter corresponding to standard pipe sizes, fitted at each end with one Ellcon conduit fitting, lock nuts and spring lock washers; for straight runs under the car sherardized steel tube with suitable thickness of wall and inside diameter to correspond to standard; pipe size fitted at each end with one Ellcon conduit fitting, lock-nuts and spring lock washers; for runs requiring bends, "Sherarduct" with lock-nuts and spring lock washers. By the use of this system of conduit, the weight was reduced to a great extent.

Third-Rail Collector and Knife Switch

The current collector is the usual type of overrunning shoe with rack adjustment at the ends but with a bolt adjustment in the center to take care of finer adjustments within a range of 1 in. The terminals are somewhat unusual in having a taper fit so that by removing a nut the connection may be slipped off very readily. In order to eliminate the breakage of fuses and connections due to vibration, the fuse box is spring-supported. Another feature is that the cover of the box is formed of a single arch of Hemmit molded insulation. Instead of building the box of wood with joints and fastenings, in the present construction only the base of the box is of wood, and this is covered with transite. The shoe beam is supported from the journal boxes with proper link action for any difference in movement between the two boxes from which it is carried. It has no permanent fastenings but is slipped into 1-5/8-in. deep side pockets on the side of each box. Between each shoe-beam rack and journal box is a compression spring to prevent rattling of the beam. Armored cable is used for the connections to the car body, but rigid conduit is employed as the conductor between the shoe-beams of the same truck. Castle nuts with cotters are used throughout.

In conclusion it should be noted that the main knife switch not only has a 500-amp position for the connection to the current collectors described, but also a 75-amp position. With the switch in the 75-amp position the light, compressor and heater circuits are connected to an inspection attachment within the switch box, through which line voltage may be plugged from any convenient point for inspection purposes when it is desired to have the source of power disconnected from the main circuit. This main knife switch is of single-pole double-throw break type.

NEW YORK MUNICIPAL CAR -- CHARACTERISTIC CURVES OF 160-HP TAP-FIELD MOTOR; OUTLINE DRAWINGS OF 160-HP MOTOR, USED TWO PER CAR, SHOWING ALSO ARRANGEMENTS FOR VENTILATION, OUTSIDE OIL GAGE WELLS AND ARRANGEMENT OF LEADS.

NEW YORK MUNICIPAL CAR -- COMBINED SIDE AND END VIEW OF COMPLETELY EQUIPPED CAR.

[Top] NEW YORK MUNICIPAL CAR -- AXLE SIDE, COMMUTATOR END OF MOTOR. [Bottom] NEW YORK MUNICIPAL CAR -- SUSPENSION SIDE, PINION END OF MOTOR.	NEW YORK MUNICIPAL CAR -- INTERIOR OF CONTROL CAB WITH CURTAIN RAISED. Note projection of motorman's seat, which is hinged to back of passenger seat.

NEW YORK MUNICIPAL CAR -- SWITCH GROUP-CONTROL BOX WITH WIRING AND PIPING COMPLETE, OPENED TO SHOW THE MAIN SWITCHES AND PK HEAD. J, G, J R and M2 are main bridging switches for going from series to parallel. LS-l and LS-2 are circuit-breaker switches which open on overloads and short-circuits.	NEW YORK MUNICIPAL CAR -- SWITCH GROUP-CONTROL BOX CLOSED WITH EXTENDED ARC CHUTES OF CIRCUIT-BREAKER SWITCHES EXPOSED.

NEW YORK MUNICIPAL CAR -- TWO VIEWS OF THE UNDERFRAME, SHOWING ARRANGEMENT OF AIR AND ELECTRICAL APPARATUS AND THE LAYOUT OF THE CONDUIT.

NEW YORK MUNICIPAL CAR -- ORIGINAL SCHEMATIC LAYOUT OF EQUIPMENT AND CONNECTIONS TO MASTER CONTROLLERS AS SUBMITTED BY THE MAKER; THE LAYOUT ON THE CAR IS SOMEWHAT DIFFERENT, BUT THE EQUIPMENT IS THE SAME.

NEW YORK MUNICIPAL CAR -- OUTLINES OF SWITCH GROUP, PK HEAD AND REVERSER.	NEW YORK MUNICIPAL CAR -- CROSS-SECTION THROUGH UNIT SWITCHES.

NEW YORK MUNICIPAL CAR -- SIDE ELEVATION OF COMMUTATING SWITCH -- SCHEMATIC DIAGRAM OF MAIN CIRCUITS AND SEQUENCE OF SWITCHES.

NEW YORK MUNICIPAL CAR -- DETAILS OF THIRD-RAIL CURRENT COLLECTOR AND SPRING-SUPPORTED FUSE BOX MADE WITH COVER OF MOLDED INSULATION.

NEW YORK MUNICIPAL CAR -- MOTOR TRUCK CARRYING FUSE BOX WITH COVER OF MOLDED INSULATION.

Sources: Electric Railway Journal, McGraw Hill Company, Digitized by Microsoft, Americana Collection, archive.org.