By cutting in such resistance--by the simple expedient of turning the rheostat handle on the switchboard,--the field coils are so weakened that the voltage is kept at the desired point in spite of the excessive speed of the machine.
Turn the rheostat handle gradually; as you advance it, the voltmeter needle will advance.
This is done by means of a starting rheostat, similar to the regulating rheostat on the dynamo switchboard.
But within a wide range, the switchboardrheostat can be used for voltage regulation.
Regulating Voltage at Switchboards The voltage of any given machine may be regulated, within wide limits, by means of the field rheostat on the switchboard.
If it registers too high, reduce the voltage of the generator slightly, by means of the field rheostat connected to the generator.
If he did, he could walk over to his generating station, and raise the voltage a further 7 volts by turning the rheostat handle another notch.
If you have designed your transmission line for a drop of 5 volts at half-load, advance the rheostat handle still further, until the needle points to 115 volts.
He was busy with a rheostatthat made thunderous roaring of the blast behind their ship: that swung them in a sweeping arc through velvet skies, away from the far side of the moon, to follow the path of the setting sun--homeward bound.
He moved the rheostat under his hand, and the thunder slackened.
How to Make a Lead Pencil Rheostat [145] Take an ordinary lead pencil and cut seven notches at equal intervals on the pencil down to and around the lead, leaving it bare.
I have been using the same method for my waterrheostat (homemade).
If a gradual transformation is desired, a double-pointed rheostat could be used, so that as one light dims the other increases in brilliancy, by the insertion and removal of resistance coils.
The outer ends of the five platinum wires are soldered to ordinary copper wires and connections made to various points on a rheostatas shown.
How to Make a Water Rheostat [78] A water rheostat may be made by fitting a brass tube with a cork, through which a piece of wire is passed.
A resistance for the arc may be made by running the current through a water rheostat or through 15 ft.
When using on a 110-volt circuit there must be some resistance in connection, which may be had by using German silver wire, or a water rheostat heretofore described.
A Simple Battery Rheostat [445] A spring from an old shade roller is mounted on a board 4 in.
The best way to add salt to a liquidrheostat is to make a strong solution in a separate vessel and add as much of this solution as is needed.
The switch and rheostat must be located within sight of the motor, except in cases where special permission to locate them elsewhere is given, in writing.
A is equipped with the ordinary motor-starting rheostat only.
Where the circuit-breaking device on the motor-starting rheostat disconnects all wires of the circuit, the switch may be omitted.
In the above case, 110 volts and a rheostat with 2.
Where the circuit-breaking device on the motor-starting rheostat disconnects all wires of the circuit, the switch called for in this section may be omitted.
A field rheostat is provided to adjust the field strength of B.
The field strength may be further regulated by the rheostat R.
The heating of a rheostatis proportional to the square of the current it carries.
If a reactance is used in place of a rheostat in an alternating-current circuit, the loss of energy is greatly reduced.
Bolts for supporting the rheostat shall be countersunk at least one-eighth inch below the surface at the back of the slab and the bolt heads shall be covered with insulating material.
The speed of each horse, moreover, can be regulated at will by means of a rheostat interposed in its particular circuit.
A rheostat is placed in shunt with the series winding so that the current passing through the winding may be regulated to control the voltage of the machine.
A rheostat is placed in series with the field coils, and by varying the resistance, more or less current will flow through the coils, thus regulating the field strength.
The method of varying the current through the field coils by means of a rheostat inserted in series with the field winding as shown in fig.
Neither for this reading, however, nor for the following readings of the test should the field rheostat be altered.
It may seem unnecessary to employ a rheostat in each of two separate field circuits to regulate the voltage of the alternator, but these rheostats are not both used to produce the same result.
It is obtained practically in the same manner as for the shunt characteristic curve, except that no field rheostat is employed.
Reduce driving power until the load has been transferred to the other alternators, adjusting fieldrheostat to obtain minimum current; 2.
If the dynamo be compound wound, the equalizing switch will generally be mounted on the frame of the machine, and in some cases the field rheostat will be operated from a pillar mounted in front of the switchboard gallery.
A rheostat for steadying and adjusting the current should be connected in series with the motor.
When a considerable variation of pressure is required, the exciter rheostat is manipulated, whereas for a fine adjustment of voltage the alternator rheostat is preferably employed.
By varying the field excitation with a rheostat in the alternator field circuit.
The rheostat is now in the field circuit, the voltage at once falls off, the main contacts are closed, and relay armature released, and shunt circuit across the rheostat again completed.
Several sets of readings are taken, with successive reductions of waterrheostat resistance.
The rheostatcan be mounted back of the switchboard on brackets bolted to the car super-structure.
The electrodes of the water rheostat should be adjusted for maximum resistance and main circuit closed, and a second set of readings taken.
This counter-electro-motive force, which develops while the machine is in motion, makes it unnecessary to hold back the current longer by the extra resistance of the rheostat and hence that is usually cut out.
The wires t and u form a loop from the armature of the motor and connect this rheostat in series with the armature.
When the welder switch is closed in making a weld, that portion of the rheostat resistance between two arms determining the voltage is short circuited.
The Dim-a-lite attachment is a lamp socket in which is enclosed a miniature rheostat or resistance unit.
You can assemble a resistance which will do fairly well if you will buy a small rheostat which will give a resistance varying by steps of ten ohms from zero to one hundred ohms.
The rheostat is mounted in the end of the potentiometer as shown in fig.
A hand regulator or rheostat R may be inserted in series with the battery or dynamo circuit to regulate the strength of the current passing.
Care should be taken, in starting the motor, that the handle of the rheostat be not rotated too fast.
When both plugs are in, therheostat slide wires are in series with the potentiometer circuit.
Since therheostat coils are adjusted to an accuracy of only 1/5 of 1 per cent.
In this test only one of the two regular bridge arms is used, the other being replaced by the rheostat giving an arm of large adjustment.
One of the commonest errors is to select a rheostat of insufficient capacity.
When the rheostat has been set to secure a balance, insert the large plug at 1, set the switch on E.
If it move toward +, the rheostat resistance is too high; if toward -, too low.
This gives the greatest resistance in the rheostat circuit.
If the galvanometer deflect, the regulating rheostat must again be adjusted until the galvanometer shows no deflection.
The rheostat lever P is then moved to the first contact to allow a moderate amount of current to pass through the armature.
Open the main knife switch and let the starting rheostat take care of itself.
The single pole switch is then closed and as the exciter field rheostat is short circuited, the exciter voltage will at once rise and bring up the voltage of the alternator.
This value depends upon the setting of the regulating rheostat in parallel with the pressure coil of the ammeter.
The rheostat is first turned in until the exciter voltage is greatly reduced and the regulator circuit is then closed.
This short circuits the rheostat through contacts in the regulator and the voltage of the exciter and alternator immediately rise.
A starting compensator is similar to a rheostat except that inductive windings are used in place of the resistance grids.
In construction,~ the control magnet is connected in series with the alternating current control magnet on the regulator and the contacts are connected in series with the rheostat shunt circuit.
The main contacts will then be again closed, the exciter field rheostat short circuited through the relay contacts and the cycle repeated.
Set the vacuum tube amplifier back of the rheostat and the A and B batteries back of the parts or in any other place that may be convenient.
A rheostatthat has a resistance of 6 ohms and a current carrying capacity of 1.
Then set the variable condenser in front of it, set the vacuum tube detector at the right hand end of the tuning coil and the rheostat in front of the detector.
The rheostat for regulating the battery current is the same as that used in the preceding experimental transmitter.
Rheostat for the A or Storage-battery Current (A) Fig.
As with the receptors a rheostat is needed to regulate the current that heats the filament.
This done connect the other terminal of the filament to one post of the rheostat and the other post of this to the - or negative side of the A battery.
The rheostat consists of an insulating and a heat resisting form on which is wound a number of turns of resistance wire.
Next connect one end of the resistance coil of the rheostat to one of the posts of the amplifier tube that leads to the filament and the other filament post to the + or positive electrode of the A battery.
A rheostat is also useful in that it keeps the filament from burning out when the current from the battery first flows through it.
A rheostat of this kind is shown at I and is listed at $1.
By means of the rheostat the current through the lamp is adjusted until the brightness of the filament is just equal to the brightness of the image produced by the lens L, Fig.
The variable rheostat R is then adjusted until the current flowing is such that as it flows through the standard resistance CD, the fall in potential between C and D is just equal to the voltage of the standard cell SC.
Never turn up the rheostat without watching the lamp.
The rheostat having been previously adjusted to heat the electrode to nearly white heat, the circuit is broken and the electrode introduced cold.
Each group has its own rheostat and pair of binding posts.
Slowly he closed the rheostat and put the power into the coil.
He waited, but when nothing more startling occurred, he gave the rheostat a sharp turn.
To the left of this coil was a large relay switch, and a rheostat control.
Diagram of rheostat and resistances in series with it 36 19.
At the left is the regulating rheostat and motor and snap-switch.
The rheostat for heating the air-spaces and the returning air-current about the zinc wall is placed on the observer's table and is indicated in the diagram as R{2}.
One end of the rheostat is connected directly with the 110-volt circuit through the main switch S{5}.
The electric motor is provided with a snap-switch on one of the posts of the table and a regulating rheostat which permits variations in the speed of the motor and consequently in the ventilation produced by the blower.
The details of these resistances and their connection with the rheostat are shown in fig.
One end of the rheostat is connected directly with the 110-volt circuit.
Diagram of rheostat and resistances in series with it.
To vary the current passing through the manganin heating coils in the air-spaces next the zinc wall, a series of resistances is installed connected directly with the rheostat R{2} in fig.
The motion of the boat in the fire-rimmed window kept drawing it swiftly away from us, and Charlie showed me how to move the dial of his rheostat to keep the girl in view.
Charlie fell to adjusting his rheostat and switches.
He manipulated the rheostat that controlled the current through the electromagnet, and continued to read his instruments.
O; the receiving coil and the sendingrheostat being marked with the same divisions.
We have now two sets of apparatus, alike in all respects, one sending rheostat at right angles to the other; one receiving solenoid at right angles to its mate.
Let us suppose our rheostat at V connected with a circuit extended to the receiving station.
We place a second rheostat along the foot of our sending tablet, not along its side, and slide a second wire along its bared surface with motions always parallel to those of the marking pencil.
Quickly Made Rheostat A short time ago I found it necessary to melt some silver, and in setting up an arc light to obtain the heat I made a rheostat by winding wire around a large earthenware jar.
Illustration: Diagram Showing the Connections for a Small Motor Where a Rheostat Is in the Line (Fig.
Such a rheostat can be purchased from an electrical store, but if the person constructing the shocking machine desires to make one, it is not difficult if a lathe is at hand.
The binding post E of the rheostat is connected to the base binding post J.
The rheostat controls the amount of current passing through the hand pieces.
Such a rheostat may be used in combination with a special switch F.
This can, however, be accomplished by means of a small rheostat placed in series with the motor.
The rheostat acts in an electrical circuit in just the same way a valve does in a hydraulic circuit.
The rheostat is of the miniature-battery type, which has a round base and a coil of resistance wire with a lever passing over the coil.
Illustration: Detail of the Upper and Lower End Plates That are Used in Making a Rheostat (Fig.
Illustration: The Rheostat That is Used to Regulate the Flow of Current in the Carbon Hand Pieces (Fig.
The connections for the buzzer and rheostat are made on the under side of the base, where grooves are cut to run the wires in, so that they will be below the surface of the wood.
The rheostat is now complete with the exception of a coat of shellac.
A very simple and inexpensive rheostat may be constructed as follows: Procure a piece of thin fiber, about 1/16 in.
Illustration: Diagram of a Small Motor Where a Rheostat and Switch Are in the Line (Fig.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "rheostat" in a variety of sentences. We hope that you will now be able to make sentences using this word. Other words: device; generator; parts; relay
