18WuD2x

350 hypersonic • hysteresis error
hypersonic
Pertaining to speeds of at least five
times that of sound. In air at normal atmospheric
pressure, such speeds are more than approximately
1700 meters, or 5600 feet, per second.
hypersonic speed Any speed greater than five
times the speed of sound in a given medium.
hypersyn motor A high-efficiency, high-powerfactor
synchronous motor combining the advantages
of the direct-current-excited synchronous
motor (stiffness), the hysteresis motor (synchronizing
torque), and the induction motor (high
starting torque).
hypervelocity Velocity in excess of 3 kilometers
per second.
hypotenuse The side of a right triangle opposite to
the right angle.
Hypotenuse
causing magnetization to lag behind the magnetizing
force. 2. A similar electrostatic action in a
ferroelectric dielectric material. 3. In a servo
system, the condition in which a variable quantity
lags the effect or stimulus that causes it to
change. The plot for this is a double-line HYS-
TERESIS CURVE.
hysteresis brake A brake whose retarding action
comes from hysteresis in a permanent-magnet
motor.
hysteresis clutch A magnetic clutch whose output
torque (for synchronous drive or continuous slip)
comes from hysteresis in a permanent-magnet
motor.
hysteresis coefficient In a sample of iron whose
volume is one cubic centimeter, the energy in
ergs dissipated during one cycle of magnetization.
Also called coefficient of hysteresis.
hysteresiscope An oscilloscope that is specially
designed to display the hysteresis curve of a material.
Compare HYSTERESIGRAPH.
hysteresis curve A response curve depicting hysteresis
in a magnetic material, a dielectric, or a
servo system. A graph of the extent to which a
variable quantity lags the effect or stimulus that
causes it to change (e.g., a curve showing the effect
of response delay in a thermostatically controlled
heating/cooling system).
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Hypotenuse
hypothesis An idea, concept, or system that seems
true or workable, but must be subjected to logical
analysis and/or practical testing to prove its validity.
hypsometer An altimeter in which a thermistor
(connected to a battery and current meter) is immersed
in a boiling liquid. Because the liquid’s
boiling point is proportional to altitude, it affects
the resistance of the thermistor and, hence, the
deflection of the meter.
hysteresigram The hysteresis-curve record produced
by a HYSTERESIGRAPH.
hysteresigraph A graphic recorder that displays or
records the hysteresis curve for a material. Also
see HYSTERESISCOPE.
hysteresimeter See HYSTERESIS METER.
hysteresis 1. The tendency of a magnetic material
to saturate and retain some of its magnetism
after the alternating magnetic field to
which it is subjected reverses polarity, thus
Heating
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65 70 75
Temperature, Fahrenheit
hysteresis curve
Cooling
hysteresis cycle A complete hysteresis curve.
hysteresis distortion Signal distortion in ironcore
components, such as coupling transformers,
resulting from hysteresis in the iron.
hysteresis error In a meter, a difference in indications
for increasing and decreasing current, an
effect caused by hysteresis in iron meter parts.
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