Page 197 - An Introduction To Predictive Maintenance

Thermography 187

X-ray Electromagnetic waves of short wavelength
from .00001ang. to 3,000ang.

APPENDIX 8.3 Electrical Terminology

Alternating current (AC) Electrical current that reverses direction
periodically, expressed in hertz (Hz) or
cycles per second (cps).

Alternator An AC generator that produces alternating
current, which is internally rectified to
direct current before being released.
Ampacity A term used to describe the current-
handling capacity of an electrical device.
Amperage A term synonymous with current; used in
describing electrical current. The total
amount of current (amperes) flowing in a
circuit.
Ampere The quantitative unit measurement of elec-
trical current.
Armature The main power winding in a motor in
which electromotive force is produced,
usually the rotor of a DC motor or the stator
of an AC motor.

Arrester A device placed from phase to ground
whose nonlinear impedance characteristics
provide a path for high-amplitude
transients.

Attenuator A passive device used to reduce signal
strength.

Brush A piece of conducting material, which,
when bearing against a commutator, slip
ring, or the like will provide a passage for
electrical current.
Capacitor A discrete electrical device that has two
electrodes and an intervening insulator,
which is called the dielectric. A device used
to store an electrical charge.
Circuit (closed) An electrical circuit in which current flow
is not interrupted.