Voltmeters are removed and the armature short circuited with the ammetersin circuit.
The field current is then varied, the armature driven at synchronous speed, and the armature current measured by the ammeters in circuit.
In ammeters for small currents it is customary to pass the whole current through the heating wire.
For switchboard use in electric supply stations where space is valuable, instruments of the type called edgewise ammeters are much employed.
Hot-wire ammeters are, however, liable to a shift of zero, and means are always provided by some adjusting screw for slightly altering the sag of the wire and so adjusting the index needle to the zero of the scale.
From this it follows that hot-wire ammeters are generally not capable of giving visible indications below a certain minimum current for each instrument.
Another large class of ammeters depend for their action upon the fact that an electric current creates an electric field round its conductor, which varies in strength from point to point, but is otherwise proportional to the current.
The calibration of ammeters is best conducted by means of a series of standard low resistances and of a potentiometer (q.
Hot-wire ammeters are open to the following objections:--The scale divisions for equal increments of current are not equal in length, being generally much closer together in the lower parts of the scale.
The sensitiveness of this instrument is such that it may be substituted in numerous cases for the non-portable reflecting type of galvanometer; as for instance, in the checking of ammeters and voltmeters to an accuracy of .
Ammeters and voltmeters, which are simply special forms of galvanometer, and which are largely used are fully described in the preceding chapter.
How are shunt ammeters arranged to correctly measure the current?
According to the principle of operation, ammeters and voltmeters are classified as: 1.
How does the winding differ inammeters and voltmeters?
Instruments called galvanometers and ammeters for the most part operate on this principle.
Ammeters to measure the volume, and voltmeters to determine the pressure of current supplied to the baths, should also be provided.
Footnote 11: If you can afford to buy, or if you can borrow, ammeters and voltmeters of the proper range you should take the characteristic yourself.
The ammeters and voltmeters which we use for the measurement of audion characteristics and the like are usually electromagnetic instruments.
In the case of ammeters we sometimes let all the current go through the current-measuring part but generally we let only a certain fraction of it do so.
Ammeters and voltmeters are alike in their design.
The panel which carries the standard instruments also carries ammeters used to measure current to auxiliary circuits in the power house.
Each vertical row comprises the ammeters belonging to the feeders which supply a given sub-station, and from left to right these are in order sub-stations Nos.
Ayrton and Perry lately described and exhibited before the Physical Society their new ammeters and voltmeters, also a non-sparking key.
The well known ammeters and voltmeters of the authors used for electric light work are now constructed so as to dispense with a constant, and give the readings in amperes and volts without calculation.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "ammeters" in a variety of sentences. We hope that you will now be able to make sentences using this word.
