Holders.
(a) The adjustable clamps for holding the armature brushes of dynamos
and motors.
(b) The clamps for holding the carbons of arc lamps.
(c) The clamps for holding safety fuses, q. v.
(d) Holders for Jablochkoff candles and other electric candles. (See
Candle Holders.)
(e) A box or block of porcelain for holding safety fuses.
Hood.
A tin hood placed over an arc-lamp. Such hoods are often truncated cones
in shape, with the small end upwards. They reflect a certain amount of
light besides protecting the lamp to some extent from rain.
Horns.
The extensions of the pole pieces of a dynamo or motor. (See Following
Horns-Leading Horns.)
Synonym--Pole Tips.
Horse Power.
A unit of rate of work or activity. There are two horse powers.
The British horse power is equal to 33,000 pounds raised one foot per
minute, or 550 foot pounds per second, or 1.0138 metric horse power.
The metric horse power (French) is equal to 75 kilogram-meters, or 542
foot pounds per second, or .986356 British horse power.