AI-1
APPENDIX I
GLOSSARY
ACCELERATION SERVO SYSTEM—A servo system that controls the acceleration (rate of
change in velocity) of a load.
ACCELEROMETER—A device that measures acceleration to which it is subjected and
develops a signal proportional to it.
ANGULAR POSITION—The counterclockwise angular displacement of a synchro rotor,
measured in degrees from its electrical zero position, as viewed from the shaft extension end
of the synchro.
APPARENT DRIFT—The effect of the Earth's rotation on a gyro, which causes the spinning
axis to appear to make one complete rotation in one day. Also called APPARENT
PRECESSION or APPARENT ROTATION.
APPARENT PRECESSION—See apparent drift.
APPARENT ROTATION—See apparent drift.
AXIS—A straight line, either real or imaginary, passing through a body, around which the body
revolves.
BANDWIDTH—The range of frequencies a servo amplifier can amplify without causing
unacceptable distortion to the input signal.
CONTROL DIFFERENTIAL TRANSMITTER (CDX)—A type of synchro that transmits
angular information equal to the algebraic sum or difference of the electrical input supplied
to its stator, and the mechanical input supplied to its rotor. The output is an electrical voltage
taken from the rotor windings.
CONTROL SYNCHRO SYSTEMS—Synchro systems that contain control synchros and are
used to control large amounts of power with a high degree of accuracy. The electrical
outputs of these systems control servo systems, which in turn generate the required power to
move heavy loads.
CONTROL SYSTEM—A group of components, systematically organized to perform a specific
control purpose. These systems are categorized as either closed- or open-loop systems. The
main difference between the two is that the closed-loop system contains some form of
feedback.
CONTROL TRANSFORMER (CT)—A type of synchro that compares two signals: the
electrical signal applied to its stator and the mechanical signal applied to its rotor. The output
is an electrical voltage, which is taken from the rotor winding and is used to control a power
amplifying device. The phase and amplitude of the output voltage depend on the angular
position of the rotor with respect to the magnetic field of the stator.
