Central Station Distribution or Supply.
The system of supplying electric energy in current form from a main
generating plant to a district of a number of houses, factories, etc. It
is in contrast with the isolated plant system in which each house or
factory has its own separate generating installment, batteries or
dynamos.
Centre of Gravity.
A point so situated with respect to any particular body, that the
resultant of the parallel attracting forces between the earth and the
several molecules of the body always passes through it. These are
resultants of the relative moments of the molecules. If a body is
suspended, as by a string, the centre of gravity always lies vertically
under its point of suspension. By two trials the point of intersection
of plumb lines from the point of suspension being determined the centre
of gravity is known. The vertical from the point of support coincides
with the line of direction.
Centre of Gyration.
The centre of gyration with respect to the axis of a rotating body is a
point at which if the entire mass of the body were concentrated its
moment of inertia would remain unchanged. The distance of this point
from the axis is the radius of gyration.
Centre of Oscillation.
The point referred to in a body, suspended or mounted to swing like a
pendulum, at which if all the mass were concentrated, 1t would complete
its oscillations in the same time. The distance from the axis of support
to this point gives the virtual length of the pendulum which the body
represents.
Centre of Percussion.
The point in a suspended body, one free to swing like a pendulum, at
which an impulse may be applied, perpendicular to the plane through the
axis of the body and through the axis of support without shock to the
axis. It is identical with the centre of oscillation, q. v., when such
lies within the body.
Centrifugal Force.
The force which draws a body constrained to move in a curved path away
from the centre of rotation. It is really due to a tangential impulse
and by some physicists is called the centrifugal component of tangential
velocity. It has to be provided against in generator and motor
armatures, by winding them with wire or bands to prevent the coils of
wire from spreading or leaving their bed upon the core.