The Standard Electrical Dictionary Part 171

(b) The Electric Flyer. (See Flyer, Electric.)

Wimshurst Electric Machine.

An influence machine for producing high potential or static electricity.

Two circular discs of thin gla.s.s are mounted on perforated hubs or bosses of wood or ebonite. Each hub has a groove turned upon it to receive a cord. Each disc is sh.e.l.lacked. They are mounted on a horizontal steel spindle so as to face and to be within one-eighth of an inch of each other. On the outside of each disc sixteen or eighteen sectors of tinfoil or thin metal are cemented.

578 STANDARD ELECTRICAL DICTIONARY.

Two curved bra.s.s rods terminating in wire brushes curved into a semi-ellipse just graze the outer surfaces of the plates with their brushes. They lie in imaginary planes, pa.s.sing through the axis of the spindle and at right angles from each other.

Four collecting combs are arranged horizontally on insulating supports to collect electricity from the horizontal diameters of the discs. These lie at an angle of about 45? with the other equalizing rods. Discharging rods connect with the collecting combs.

The principle of the machine is that one set of sector plates act as inductors for the other set. Its action is not perfectly understood.

It works well in damp weather, far surpa.s.sing other influence machines in this respect. On turning the handle a constant succession or stream of sparks is produced between the terminals of the discharging rods.

Windage.

In a dynamo the real air gap between the armature windings and pole pieces is sometimes thus termed.

Wind, Electric.

The rush of air particles from a point connected to a statically charged condenser.

Winding, Compound.

A method of winding a generator or motor in which a shunt winding is used for the field magnets and in which also a second winding of the magnet is placed in series with the outer circuit. (See Winding, Series--Winding, Shunt.)

Fig. 350. CHARACTERISTIC CURVES OF SHUNT AND SERIES WINDING.

The object of compound winding is to make a self-regulating dynamo and this object is partly attained for a constant speed.

The characteristic curves of shunt and series winding are of opposite natures. The first increases in electro-motive force for resistance in the outer circuit, the latter decreases under the same conditions. If the windings are so proportioned that these conditions for each one of the two windings are equal and opposite, it is evident that the characteristic may be a straight line. This, however, it will only be at a single speed of rotation.

579 STANDARD ELECTRICAL DICTIONARY.

Winding, Disc.

A winding which (S. P. Thompson) may be treated as a drum winding extended radially, the periphery corresponding to the back end of the drum. The magnet poles are generally placed so as to face the side or sides of the disc.

Winding, Lap.

A method of winding disc and drum armatures. It consists in lapping back each lead of wire towards the preceding lead upon the commutator end of the armature. Thus taking the letter U as the diagrammatical representation of a turn of wire in connecting its ends to the commutator bars they are brought towards each other so as to connect with contiguous commutator bars. This carries out the principle of keeping the two members of the U moving in regions of opposite polarity of field, so that the currents induced in them shall have opposite directions, thus producing a total current in one sense through the bent wire.

Winding, Long Shunt.

A system of compound winding for dynamos and motors. The field is wound in series and, in addition thereto, there is a shunt winding connected across from terminal to terminal of the machine, and which may be regarded either as a shunt to the outer circuit, or as a shunt to the series-field and armature winding. (See Winding, Short Shunt.)

Synonyms--Series and Long Shunt Winding.

Winding, Multiple.

A winding of an electro-magnet, in which separate coils are wound on the core, so that one or any number may be used as desired in parallel or in series. For each coil a separate binding post should be provided.

Winding, Multipolar.

Winding adapted for armatures of multi-polar dynamos or motors.

Winding, Series.

A method of winding a generator or motor, in which one of the commutator-brush connections is connected to the field-magnet winding; the other end of the magnet winding connects with the outer circuit. The other armature-brush connects with the other terminal of the outer circuit.

Winding, Series and Separate Coil.

A method of automatic regulation applied to alternating current dynamos.

Winding, Short Shunt.

A method of compound winding for dynamos and motors. The field is wound in series, and in addition thereto there is a shunt winding connected from brush to brush only, thus paralleling the armature. (See Winding, Long Shunt.)

Synonyms--Series and Short Shunt Winding.

580 STANDARD ELECTRICAL DICTIONARY.

Winding, Shunt.

A method of winding a generator or motor. Each commutator-brush has two connections. One set are the terminals of the outer circuit, the other set are the terminals of the field-magnet windings. In other words, the field-magnet windings are in shunt or in parallel with the outer circuit.

Winding, Shuttle.

A method of dynamo or motor-armature winding. A single groove pa.s.ses longitudinally around the core and in this the wire is continuously wound. The system is not now used. The old Siemens' H armature ill.u.s.trates the principle.

Winding, Wave.

A method of winding disc and drum armatures. It consists in advancing the commutator ends of the U shaped turns progressively, so that as many commutator bars intervene between any two consecutive commutator connections of the wire as there are leads of wire on the drum between consecutive leads of the wire. This is carried out with due regard to the principle that taking the letter U as the diagrammatical representation of a turn of wire, its two members must move through regions of the field of opposite polarity.

Wire Finder.

A galvanometer or other instrument used for identifying the ends of a given wire in a cable containing several.

Work.