464 ELECTRICAL APPARATUS
and the machine thus a synchronous induction generator. In
concatenation, the first machine always acts as frequency con-
verter. The frequency converter has the advantage of lesser
machine capacity than the motor generator, but the disadvantage
of not being standard yet.
Heyland Motor.—59, 210. Squirrel-cage induction motor with
commutator for power-factor compensation.
Hunt Motor.—36. Internally "concatenated induction motor.
(See " Concatenation (1).")
Hysteresis Motor.—X, 98. Motor with polyphase stator and
laminated rotor of uniform reluctance in all directions, without
winding. Gives constant torque at all speeds, by the hysteresis
of the rotor, as motor below and as generator above synchronism,
while at synchronism it may be either. .Poor power-factor and
small output make it feasible only in very small sizes, such as
motor meters.
Inductor Machines.—XVII, 156. Synchronous machine, gen-
erator or motor, in which field and armature coils stand still and
the magnetic field flux is constant, and the voltage is induced by
changing the- flux path, that is, admitting and withdrawing the
flux from the armature coils by means of a revolving inductor.
The inducing flux in the armature coils thus does not alternate,
but pulsates without reversal. For standard frequencies the
inductor machine is less economical arid little used, but it offers
great constructive advantages at high frequencies and is the only
feasible type at extremely high frequencies. Excited by alter-
nating currents, the inductor machine may be used as amplifier
(see "Amplifier"); excited by polyphase currents, it is an induc-
tion inductor frequency converter, 162; with a direct-current wind-
ing on the inductor, it is a direct-current high-frequency converter.
(See "Eickemeyer Inductor Alternator.")
Leading current, power-factor compensation and phase control
can be produced by:
Condenser.
Polarization cell.
Overexcited synchronous motor or synchronous converter.
Induction machine concatenated to condenser, to synchronous
motor or to low-frequency commutating machine.
Alternating-current commutating machine with lagging field
excitation.
I/eblanc'sPanchahuteur,—145, Synchronous rectifier of many