The Standard Electrical Dictionary Part 21

Bell, Automatic Electric.

A bell which rings as long as the circuit is closed, having a circuit breaker operated by its own motion. (See Bell, Electric.)

Synonyms--Trembling Bell--Vibrating Bell.

Bell, Call.

A bell operated by electricity, designed to call attention, as to a telephone or telegraphic receiver. (See Bell, Electric.)

79 STANDARD ELECTRICAL DICTIONARY.

Bell Call.

A calling device for attracting the attention of any one, consisting of some type of electric bell.

Bell, Circular.

A gong-shaped bell, whose clapper and general mechanism is within its cavity or behind it.

Bell, Differentially Wound.

An electric bell, whose magnet is wound differentially so as to prevent sparking.

Fig 57. AUTOMATIC ELECTRIC BELL.

Bell, Electric.

A bell rung by electricity. Generally it is worked by a current exciting an electro-magnet, attracting or releasing an armature which is attached to the vibrating or pivoted tongue of the bell. It may be worked by a distant switch or press-b.u.t.ton, q. v., ringing once for each movement of the distant switch, etc., or it may be of the vibrating bell type as shown in the cut. When the current is turned on in this case it attracts the armature. As this moves towards the poles of the magnet it breaks the circuit by drawing the contact spring, q. v., away from the contact point, q. v. This opens the circuit, to whose continuity the contact of these two parts is essential. The hammer, however, by its momentum strikes the bell and at once springs back. This again makes the contact and the hammer is reattracted. This action continues as long as the circuit is closed at any distant point to which it may be carried. The ordinary vibrating bell is a typical automatic circuit breaker, q. v., this type keeping up the ringing as long as the circuit is closed. Other bells have no electric contact and simply ring once every time the circuit is closed. Others worked by an alternating current ring once for each change of direction of current.

80 STANDARD ELECTRICAL DICTIONARY.

Bell, Electro-mechanical.

A bell which has its striking train operated by a spring or descending weight, and which train is thrown into action by the release of a detent or equivalent action by the closing of an electric circuit. It rings for any given time after being started.

Bell, Indicating.

A bell which by drop-shutter or other indicator connected in circuit with it, indicates its number or other designation of its call.

Bell, Magneto.

An electric bell operated by the alternating current from a magneto generator. It has a polarized armature and no circuit breaker. The armature is attracted first in one direction and then in the other, as the current alternates and reverses the polarity of the electro-magnet.

Bell, Relay.

A bell operated by a relay circuit.

Bias.

In polarized relay the adjustment of the tongue to lie normally against one or the other contact. (See Relay, Polarized.)

81 STANDARD ELECTRICAL DICTIONARY.

Fig. 58. RESISTANCE COILS SHOWING BIFILAR WINDING.

Bifilar Winding.

The method followed in winding resistance coils to prevent them from creating fields of force. The wire is doubled, and the doubled wire starting with the bend or bight is wound into a coil. The current going in opposite senses in the two lays of the winding produces no field of force.

Binary Compound.

A chemical compound whose molecule contains only two elements, such as water (H2 0), lead oxide (Pb 0), and many others.

Binding.

In a dynamo or motor armature the wire wound around the coils to secure them in place and prevent their disturbance by centrifugal action.

Fig. 59. DOUBLE BINDING POST.

Fig. 60. BINDING POST, ENGLISH PATTERN.

FIG. 61. WOOD SCREW BINDING POST.

Binding Posts or Screws.

Arrangements for receiving the loose end of a wire of an electric circuit, and securing such end by a screw. Several constructions are used, as shown here. Sometimes the wire is pa.s.sed through a hole, and a screw tapped in at right angles to the hole is screwed down upon the wire. Sometimes the wire is clamped between two shoulders, one on the screw, the other on the post. The screw is often a flat-headed thumb screw or has a milled edge. Sometimes the screw has a slot and is turned by a screw-driver.

Several openings are often provided in the same post for different wires.

Binnacle.

The case containing a mariner's compa.s.s on s.h.i.+pboard. It is enclosed completely; it has a gla.s.s side or window through which the compa.s.s can be seen, and is provided with one or two lamps arranged to light the card, while showing as little light as possible outside.

82 STANDARD ELECTRICAL DICTIONARY.

Bioscopy, Electric.

The diagnosis of life and death by the action of the animal system when subjected to an electric current or electrification.

Bis.m.u.th.