It may be remarked in passing that experimenting with large high-tension transformers coupled to condensers of large capacity is exceedingly dangerous work, and the greatest precautions are necessary to avoid accident.
In the construction of transformers intended to be used in this manner, very special precautions have to be taken in the insulation of the primary and secondary circuits, and the insulation of these from the core.
In constructing these transformers we have to set aside all previous notions gathered from the design of low-frequency iron-core transformers.
Electrical transformers are the most efficient of all machines.
The three, transformers cut off, were back in the middle room of their suite.
The method of connecting ordinary distributing transformers to constant pressure mains is shown by the elementary diagram, fig.
An improved type of transformer has been introduced which can be considered either as two superposed shell transformers with coils in common, or as a single core type transformer with divided magnetic circuit and having coils on only one leg.
What kinds of transformers are used for three phase current?
The connections of three transformers for a low tension system of distribution by the four wire three phase system are shown in fig.
Two single phase transformers are used and connections made just as though each phase were an ordinary single phase system.
No specific rule can be given regarding the selection of single phase or three phase transformers since both designs are equally reliable; local conditions will generally determine which type is preferable.
Water cooled transformers may be divided into two classes, as those having: 1.
The connections for a three phase motor using two transformers is shown in fig.
When the secondaries of three transformers are star connected, a fourth wire may be run from the neutral point, thus obtaining the four wire system.
This name is given to all transformers which are cooled by currents of air without regard to the manner in which the air is circulated.
The terminals must have the same polarity at a given instant, and the transformers should have practically identical characteristics.
The proper rating of transformers for two phase and three phase induction motors is given in table on the next page.
In the case of two phase distribution each circuit may be treated as entirely independent of the other so far as the transformers are concerned.
The operating principle and further use of the transformers will be explained later under doorbell transformers.
These transformers are also used to supply current for lighting low-power tungsten lamps that cannot be used with the ordinary voltages employed in house lighting.
Muscles, then, are merely transformerswhich change chemical energy into mechanical work, the diminution of stored-up energy in a muscle being expressed by the sensation of fatigue.
The character of these early transformers and creators is that of the communities in which they originate.
But the same principle as that for the motor may also be applied to transformers themselves, as shown in Figs.
The transformersused in the Lauffen-Frankfort transmission are similar, magnetically, to Fig.
It has been found that if the sheet iron employed for cores of alternating electromagnets or transformers is heated to a temperature somewhere in the neighbourhood of 200 deg.
The secondary circuits of these transformers are generally provided with three terminals, so as to supply the low-pressure side on a three-wire system.
It is there reduced in voltage by transformers and employed as an alternating current, or is used to drive polyphase motors coupled to direct current generators to reproduce the power in continuous current form.
Partridge that alternating-current transformers which had been in use some time had a very considerably augmented core loss when compared with their initial condition.
Where the consumers lie scattered over a large area, it is necessary to carry the high-pressure mains throughout the area, and to place a separate transformer or transformers in each building.
In the latter some of the transformers can be switched off, either by hand or by automatic apparatus, during the time when the load is light, and then no power is expended in magnetizing their cores.
The pressure of the current is then transformed down by these transformers to the required supply pressure.
It is also clear that the secondary currents developed in these transformers are led to the several ringing keys so as to be available for connection with the subscribers' lines at the will of the operator.
The condensers are bridged across the primary windings of the transformers for the purpose of aiding in smoothing out the current waves.
The transformers would all be preferably in series.
In transformers and in a certain class of motors the fluctuation of the poles is not of great importance, but in another class of these motors it is desirable to obtain the theoretical result.
It is obvious that the Tesla electrical transformers which have independent primary currents may be used with the generators described.
Besides, these transformersare expensive to build.
The transformers present an additional advantage in their capability of operating motors.
In this instance, the generator which supplies the current for operating the motors or transformers consists of a subdivided ring or annular core wound with four diametrically-opposite coils, E E', Fig.
In these transformers he provides a series of inducing coils and corresponding induced coils, which are generally wound upon a core closed upon itself, usually a ring of laminated iron.
Transformers have been constructed by me on that plan, but for lack of time, no thorough tests have as yet been made.
Without a word into the transformersthey seized Bradley and Clio.
Three huge dynamo-motor arrangements took up the room's far end, and from them a tangle of wiring led through square black condensers and transformers to a battery of great tubes.
The cubical chambers had been smashed beyond all recognition, the dynamos were masses of split metal and fused wiring, the batteries of tubes were shattered, the condensers and transformers and wiring demolished.
Perhaps the most extreme case of what may be called dilution of field by projections and by closed magnetic circuits intransformers would be that of a block of iron, B, Fig.
The considerations advanced also bring out the relation which exists between closed iron circuit transformers and closed iron circuit (projection) dynamos, as we may call them.
Transformers (1) Transformers of the oil-filled type can be put out of commission if you pour water, salt into the oil tank.
First cost of transformers varies directly with the maximum rate of transmission, and is nearly independent of the voltage, the length of the transmission, and the percentage of line loss.
The use of three transformers for each three-phase generator instead of three transformers for each two or three generators, tends to keep transformers fully loaded when in use, and therefore to increase their efficiency.
If the alternating transmission uses no step-up transformers and delivers either alternating or continuous current by means of motor generators, its efficiency at full load is 83.
Transformers with approximately twice the capacity corresponding to the maximum rate of transmission must be provided, because one set is required at the generating and another at the delivery station.
The mesh or Δ-connection is used between the coils of transformers on some transmission lines of very high voltage.
Continuous current stationary motors draw power from the transmission lines through step-down transformers and rotary converters, like the railway load.
Though three-phase transformers are much used in Europe, they have thus far had little application in the United States.
Three of these larger transformers have a capacity of 2,850 kilowatts, or nearly equal to that of four generators.
The heaping up of the potential only took place when transformers were used, and not when the dynamos were connected direct.
When transformers are used, the field magnets are weak, while the condenser current rises to 40 amperes.
Great benches lined the walls, and there were hundreds of dials, meters, tubes, transformers and other instruments, whose uses Seaton could not even guess.
We may then name, as species, energy-transformers that are motors and energy-transformers that are not motors.
Then the definition will be: Energy-transformers that are adapted to continuously transform energy into cyclical mechanical motion.
In all transformers the effect is greater the more rapidly the current changes direction and the atomic loops turn around.
This whole matter of the proper use of transformersis quite simple but very important in setting up vacuum-tube circuits.
Transformers have an interesting ability to make a large resistance look small or vice versa.
The transformers were treated in the same manner as the motors, with equally gratifying results.
T~ connection of transformers in which three phase current is transformed with two transformers.
Arc lamps with individual transformersfurther reducing the pressure to 50 volts are connected to this circuit as shown.
Why is this arrangement more efficient than when individualtransformers are used?
Ordinarily and for lines of moderate length, current is sent out direct from the alternator to the line and transformed by step down transformers at the points of application.
Part of the functions of the choke coil are performed by the end turns of a transformer and extra insulation is invariably installed in all power transformers built in recent years.
The relay design and action is similar to the reverse current relay previously mentioned, and is connected to the secondaries of current transformers in each high voltage line and pressure transformers in the low voltage bus.
Power to operate relay:~ The relay requires twenty volt amperes for its operation at full load; the influence of this type of relay on the ratio and phase angle of current transformers is small.
This transformation may be accomplished by the use of two transformers connected as in fig.
Another set of step down transformers M reduce the pressure directly to 120 volts for power and lighting, the pressure being regulated by the regulators G.
If the voltage or capacity of the motor make this arrangement inexpedient, the relay may be placed in the secondaries of current or pressure transformers connected in the motor leads.
My thermic inductor transformers melted last week and I'm all in the air.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "transformers" in a variety of sentences. We hope that you will now be able to make sentences using this word.
