Switch engine

“ There was no express rule as to the speed allowed to the switch engine. Of course, the law requires that such engine should not be run at an unreasonable rate of speed under the circumstances. The engineer of the switch engine must have had a clear view of the approaching engine for at least 420 feet, and it was run at least 370 feet of this distance before the collision occurred. It could have been stopped within a distance of 60 feet unless running at a greater speed than 20 miles an hour ”

“ It is necessary to start them, of course, when light or power is desired, and to stop them when no current is being drawn. There have appeared several makes on the market in which starting and stopping are automatic. Storage batteries are used in connection with these latter plants for starting the engine. When a light is turned on, or current is drawn for any purpose, an automatic switch turns the dynamo into a motor, and it starts the engine by means of the current stored in the battery. ”

“ If one of the cylinders fires regularly, it is an indication that the current is being generated properly, and that no time need be wasted in examining the generator. By means of the switches, the igniters may be tested individually by cranking the engine with one switch closed and the others open. When the clutch is disengaged the engine should run on one cylinder, and if this is the case, the igniter on the line of the closed switch is shown to be in good condition. ”

“ It is, in fact, common practice in central stations to judge the voltage of the new dynamo merely by the appearance of its pilot lamp.
Ques. How is a machine cut out of the circuit?
Ans. When shutting down a machine, the load or current must first be reduced, by gradually closing the stop valve of the engine, or inserting resistance into the shunt circuit by means of the hand regulator; then when the ammeter indicates nine or ten amperes, the main switch is opened, and the engine stopped. ”

“ Turned to the left, the key completes the electrical circuit to the gasoline gage, radio, and other accessories but not to the ignition. The ignition key should always be removed when you leave the car.
Starter Switch The starter is controlled by a button on the toeboard located directly beneath the clutch pedal. By completely depressing the clutch pedal, the electrical circuit through the starter switch is completed. Do not operate starter when the engine is running. ”

“ For very large motors the switching device is generally separate from, the compensator itself and consists of triple and four pole switches for three phase and two phase motors respectively. One double throw switch or two interlocked single throw switches are required for the motor and a single throw switch for energizing the compensator, the running side of the motor circuit being provided with fuses or automatic circuit breakers, or the switches provided with low voltage and overload release attachments. ”

“ Where the capacity of the plant is very large, the oil switches are operated electrically by means of small motors, and in this case the small switch gear for starting and stopping this motor is mounted on the generator panel, also the lamp or lamps to indicate when the switch is open, and when closed. ”

“ With the switch the motorman can turn the current on or off completely, he can regulate the amount of current that reaches the motor so as to start gradually or go slowly in crowded places, or fast in quiet ones, and he can even reverse the motor and make the car go backwards, a thing that neither the driver of the horse-car nor the gripman of the cable-car can do. ”

“ These motors of the larger size are generally started through an auto-transformer. For the smaller ones, it is customary to provide a throw-over switch, one side only of the switch being fused. The motor at starting takes very strong currents which would blow the running fuse. To reverse a two-phase induction motor the two wires of one phase must be reversed. ”

“ Every alternator switch, every selector switch, every group switch, and every feeder switch upon the main floor is here represented by a small switch. The small switch is connected into a control circuit which receives its supply of energy at 110 volts from a small motor generator set and storage battery. ”

“ When the speed of the motor has thus been brought to the desired rate the switch is shifted to throw the main current directly through the motor-circuits, and although the currents in both circuits will now be of the same phase the motor will continue to revolve, becoming a true synchronous motor. To secure greater efficiency, the armature or its polar projections are wound with coils closed on themselves. ”

“ A direct control switchboard has all its apparatus mounted directly on the board and controlled by hand, while in the remote control type, the main current carrying parts are at some distance from the operating board, the control being effected by mechanical devices or by electric motors or solenoids. When the control system of a plant is very extensive, it sometimes occupies a separate building known as the switch house. ”

“ If the current delivered by a dynamo does not flow in the desired direction, it can be reversed by shifting the wires in the binding posts or by throwing a switch. If the motor does not revolve in the desired direction, it can be made to do so by reversing the connections to the armature or field-coils; so that, without knowing which way a current of electricity is to be generated, any practical man can make a motor revolve in a proper direction by simply changing its connections. ”

“ A controller is mounted upon the platform at each end of each motor car, and the entire train may be operated from any one of the points, the motorman normally taking his post on the front platform of the first car. The switches which open and close the power circuits through motors and rheostats are called contactors, each comprising a magnetic blow-out switch and the electro magnet which controls the movements of the switch. ”

“ NOTE.--In starting a motor, first see that the bearings contain sufficient oil and that the brushes bear evenly on the commutator. If a circuit breaker be used, close it; then close the main switch. Rotate slowly the handle of the starting rheostat as far as it will go. Care should be taken, in starting the motor, that the handle of the rheostat be not rotated too fast. To stop a motor, open the circuit breaker or switch, which will cut in the resistance of the starting box. ”

“ When a car is provided with magnetic brakes, the controlling switches are so made that when the handle h is moved back to the stop position it disconnects the motors from the trolley wire and at the same time connects them with the magnetic brakes in such a manner that they will act as generators and thus send current through the coils of the latter. In order that the force with which the brakes are applied may be graduated, the controlling switches are arranged so as to be moved several steps back of the point which in the ordinary type of switch would be the final stop position. ”

“ High wiring is carried entirely on the roof of the car where it is entirely out of the way and where the operator cannot come in contact with it. The switchboard should be of the utmost simplicity. Usually the negative and equalizer switches, and the field break-up switch are mounted on the frame of the converter. The double throw switch for starting and running the converter can be mounted under the floor of the car and operated by handle at the switchboard. The rheostat can be mounted back of the switchboard on brackets bolted to the car super-structure. ”

“ Switchmen are dispensed with by the simplest of expedients at the busiest junctions; the simple placing of an insulated rail in a track, and of disconnecting a current supplied by the car passing over it, being found to throw and replace a switch with absolutely infallible accuracy. And, again, this docile horse will not only do its own work, but anybody else's; for it has been found that where two trolley lines cross, and an accident to one withdraws its power, the power used by the other will leap over into the unoccupied wires of the disabled road and operate them both. ”

“ The chief advantage of this "composite" system of power transmission is that the engine is kept running at a constant speed, while the power it develops at the electric motors is regulated by switches which control the action of the armature and field magnets. When heavy work must be done the engine is supplied with more gaseous mixture, and the generators are so operated as to develop full power. In this manner all the variable speed gears and clutches necessary when the petrol motor is connected to the driving-wheels are done away with. ”

“ The electrically operated switches may be of the open type, mounted on a slate or marble switchboard, when the whole control outfit is placed in a room which is comparatively free from dust or dirt of any kind, and where there is no danger of employees coming in contact with the switches. The other type of switch is entirely enclosed, the main contacts being oil immersed. ”

“ Fig. 759.--Cutler-Hammer multiple switch starter with no voltage release; for use with large motors, or with motors of medium size where the starting conditions are severe or when more than fifteen seconds are required to accelerate the motor. In operation, the cutting out of each step of resistance is accomplished by a separate lever and the levers themselves are so interlocked as to prevent closing switches except in proper order, beginning with the lever on the left. ”

“ In starting an induction motor, the switch is thrown to the end that is not fused and held there until the motor is up to running speed; then it is quickly thrown to the fused position, thus protecting the circuit under running conditions.
Fig. 2,207.—Diagram of connections of Westinghouse fused starting switch for squirrel cage motors. The starting current of induction motors is several times the normal running current and, when the controlling switch is fused to carry the running load only, the fuses are apt to blow when the motor is started. ”

“ Ans. The main coils are of more turns than the auxiliary, being spread over more surface, and are heavier because they are for constant use; whereas the auxiliary coils are used only while starting.
Figs. 1,859 to 1,862.—Detail construction of clutch parts of General Electric drawn shell type fractional horse power single phase motor. The starting switch, which is assembled within the motor frame, consists essentially of three parts: a rotating member mounted on the armature and provided with two spring controlled pivoted levers in contact with an insulated collector ring. ”

“ In other instances they are formed solely through switch contacts. In all cases the control, when from a distance, is received upon relays suitable for being controlled by the small currents which are adapted to flow over long lines. In all instances the power for moving a brush is derived from the main shaft and only the control of the movement is derived from electromagnets, relays, or other electric sources. In many instances the clutch circuit is closed through contacts of its own switch and, therefore, may be closed only when its switch is in some predetermined position. ”

“ To start such a motor, the switch is turned on to a set of contacts which includes in one motor circuit a dead resistance, in the other an inductive resistance, and, the two circuits being in derivation, it is obvious that the difference in phase of the current in such circuits will set up a rotation of the motor. ”

“ It is necessary to provide each generator with means for varying the electro-motive force of the current it generates, otherwise the load could not be properly equalized between the several machines. All these different devices are located upon the switch board, so as to have them in an accessible position. A railway switch board, arranged for four generators and a large number of distributing circuits, is shown in Fig. ”

“ On each of the eleven generator panels there are two selector relay switches, one generator relay switch, and one relay generator field switch. On each of the twenty-two feeder panels there are two relay selector switches. The relay switches on the two interconnecting panels serve to make connections between the two groups of five and six generators respectively in power-house No. 2 and the ten generators of power-house No. 1. On each panel there are relay indicators to show whether the oil switches that carry the main current respond to the movements of their relay switches. ”

“ The controller switch S is so arranged that a greater or lesser number of field coils can be inserted in the field circuit. When the switch arm is 383 on point 1, the motor current will flow through all the field windings, and the strength of the field will be at its maximum. When the switch arm is moved so as to successively occupy positions 2, 3, and 4, thus cutting out of circuit a greater and greater number of field coils the strength of the field will be gradually decreased until practically all of the motor current is led or wired through the armature. ”

“ Then the chief engineer gives a shrill whistle, raises his hand, two quick wrenches at the switchboard in the electrical engine-room, a couple of blinding flashes half an inch long: the first valve-heads rise slowly, hesitatingly, as if unwilling, then quicker, a wild report and hissing, a wild irregular spluttering, then the loud explosions become rhythmical, and faster and faster both machines resume their regular vibrations. ”