Joint, Sleeve.
A joint in electric conductors, in which the ends of the wires are
inserted into and secured in a metallic sleeve or tube, whose internal
diameter is just sufficient to admit them.
Joint, Splayed.
The method of joining the ends of stranded conductors. The insulating
covering is removed, the wires are opened out, and the center wire,
heart or core of the cable is cut off short. The two ends are brought
together, the opened out wires are interlaced or crotched like the
fingers of the two hands, and the ends are wound around the body of the
cable in opposite directions. The joint is trimmed and well soldered.
Tinned wire with rosin flux for the soldering is to be recommended.
Insulating material is finally applied by hand, with heat if necessary.
Joints in Belts.
Belt-joints for electric plants where the belts drive dynamos should be
made with special care. The least inequality affects the electro-motive
force. Butt joints are, generally speaking, the best, where the ends of
the belt are placed in contact and laced. Lap-joints are made by
overlapping the belt, and unless the belt is carefully tapered so as to
preserve uniform strength, the speed of the dynamo will vary and also
the electromotive force.
Joulad.
A name proposed to be substituted for "joule," q. v. It has not been
adopted.
Joule.
This term has been applied to several units.
(a) The practical C. G. S. unit of electric energy and work--the
volt-coulomb. It is equal to 1E7 ergs--0.73734 foot pound.--.00134 horse
power seconds. A volt-ampere represents one joule per second.
(b) It has also been used as the name of the gram-degree C. thermal
unit--the small calorie.
Synonym--Joulad.
Joule Effect.
The heating effect of a current passing through a conductor. It varies
with the product of the resistance by the square of the current, or with
(C^2)*R.
Joule's Equivalent.
The mechanical equivalent of heat, which if stated in foot-pounds per
pound-degree F. units, is 772 (772.55). (See Equivalents.)
Junction Box.
In underground distribution systems, an iron casing or box in which the
feeders and mains are joined, and where other junctions are made.
Synonym--Fishing Box.
K.
The symbol for electrostatic capacity.
Kaolin.
A product of decomposition of feldspar, consisting approximately of
silica, 45, alumina, 40, water, 15. It was used in electric candles of
the Jablochkoff type as a constituent of the insulating layer or
colombin. Later it was abandoned for another substance, as it was found
that it melted and acted as a conductor.