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160 Cards in this Set

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name given to a variety of rotary, electromechanical,
position-sensing devices.
SYNCHRO
like the transformer, uses the principle of electromagnetic induction.
SYNCHRO
As the synchro transmitter shaft turns, it converts the
mechanical input into an electrical signal
required to move light loads such as dials, pointers, or similar indicators
Torque-synchro
are used in systems that are
designed to move heavy loads such as gun directors, radar antennas, and missile launchers.
Control synchros
INPUT: Mechanical input to rotor

OUTPUT: Electrical output from stator representing angular position of
rotor to TDX, TDR, or TR.
Torque transmitter TX
INPUT:Mechanical input to rotor

OUTPUT: Electrical output from stator representing angular position of
rotor to CDX or CT
Control transmitter CX
INPUT: Mechanical input to rotor, electrical input to stator from TX or another
TDX.

OUTPUT: Electric output from rotor representing algebraic sum or difference between rotor angle and angle represented by electrical input to TR, TDR, or another TDX.
Torque differential
transmitter TDX
INPUT: Mechanical input to rotor, electrical input to stator from CX or another CDX.

OUTPUT: Electric output from rotor representing algebraic sum or difference between rotor angle and angle represented by electrical input to CT or another CDX.
Control differential
transmitter CDX
INPUT: Electrical input to stator from TX or TDX.

OUTPUT: Mechanical output from rotor. Note: Rotor has mechanical inertia damper.
Torque receiver TR
INPUT: Electrical input to stator from TX or TDX, another
electrical input to rotor
from TX or TDX.

OUTPUT: Mechanical output from rotor representing algebraic sum or difference between angles represented by electrical inputs. Has inertia damper.
Torque differential
receiver TDR
INPUT:Electric input to stator
from CX or CDX, mechanical input to rotor.

OUTPUT: Electrical output from rotor proportional to the sine of the angle between rotor position and angle represented by electrical input to stator. Called error
signal.
Control transformer CT
INPUT: Depending on application, same as TX.

OUTPUT: Depending on application, same as TX or TR.
Torque receiver TRX
What is the difference between a torque synchro and a control synchro?
A torque synchro is used for light loads and a control synchro is used in systems desired to move
heavy loads.
name two synchros that provide a mechanical output.
The torque receiver (TR) and the torque differential receiver (TDR).
Military Standard Synchro Code
- first two digits indicate the diameter of the synchro in tenths of an inch.
- first letter indicates the general function of the synchro and of the synchro system-C for control or T for torque.
- next letter indicates the specific function of the synchro(D Differential, R Receiver,T Transformer,X Transmitter)
- last number in the designation indicates the operating frequency-6 for 60 Hz and 4 for 400 Hz.
- The upper-case letter following the frequency indicator is the modification designation.
synchro designation codes G
Transmitter
synchro designation codes F
Flange Mounted Receiver
synchro designation codes D
Differential Receiver
synchro designation codes DG
Differential Transmitter
synchro designation codes CT
Control Transformer
synchro designation codes H
High-Speed Unit
synchro designation codes B
Bearing Mounted Unit
synchro designation codes N
Nozzle Mounted Unit
synchro designation codes S
Special Unit
has a single coil wound on a laminated core. The core is shaped like a "dumb-bell" or the letter "H."
salient-pole rotor
has coils wound in slots in a laminated core. This
type of rotor is used in most synchro control transformers and differential units, and occasionally in torque transmitters.
drum or wound rotor
is a cylindrical structure of slotted laminations on which three Y-connected coils are wound with their axes 120º apart.
stator of a synchro
How does the stator receive its voltage?
By the magnetic coupling from the rotor.
Where are the external connections made on standard synchros?
At the terminal board.
is simply a measure of how much load a machine can turn
Torque
What unit of measurement refers to the torque of a synchro transmitter?
ounce-inch
Navy prestandard synchros are designed to operate on either
115 volts or 26 volts
Synchros are also designed to operate on a
60- or 400-Hz frequency
What type of equipment normally uses 26-volt 400-hertz synchros?
aircraft
NEVER connect a 400-Hz synchro to 60-Hz voltage, why?
The reduced impedance
results in excessive current flow and the windings quickly burn out.
When will a synchro generate more heat than it is designed to handle?
overloading
How do synchros differ from conventional transformers?
Synchros have one primary winding that can be turned through 360º and three secondary windings spaced 120º apart.
Describe the zero-position of a synchro transmitter.
The transmitter is in its zero-position when the rotor is aligned with the S2 stator winding
The synchro transmitter converts the what of its rotor (mechanical input) into a what output signal.
angular position
electrical
When is the maximum voltage induced into a stator coil?
When the rotor coil is aligned with the stator coil.
What three factors determine the amplitude of the voltage induced into a stator winding?
The amplitude of the primary voltage, the turns ratio, and the angular displacement between the
rotor and the stator winding.
convert the electrical data supplied to its stator from the transmitter, back to a mechanical angular position through the movement of its rotor
Synchro torque receivers
method of preventing
oscillations or spinning must be used
DAMPING
What is the physical difference between a synchro transmitter and a synchro receiver?
A synchro receiver uses some form of damping to retard excessive oscillations or spinning
What two components make up a simple synchro transmission system?
A synchro transmitter and a synchro receiver.
What leads in a simple synchro system are connected to the ac power line?
The rotor leads
What is the relationship between the transmitter and receiver stator voltages when their rotors
are in correspondence?
The voltages are equal and oppose each other.
What is the name given to the angle through which a transmitters rotor is mechanically rotated?
Signal.
What two receiver leads are reversed to reverse the rotor's direction of rotation?
S1 and S3.
What is the most likely problem if the transmitter shaft reads 0º when the receiver shaft indicates
180º?
The rotor leads on either the transmitter or the receiver are reversed
What is the purpose of using differential synchros instead of regular synchros?
Differential synchros can handle more signals than regular synchros and also perform addition
and subtraction functions.
What are the two types of differential synchros?
The TDX and the TDR.
Other than their physical differences, what is the major difference between a TDX and a TDR?
Their application: a TDX has one electrical and one mechanical input with an electrical output.
What determines whether a differential synchro adds or subtracts?
The way the differential synchro is connected in a system is the deciding factor on whether the
unit adds or subtracts its inputs.
In a TDX system when does the TR rotor follow the TX rotor exactly?
When the TDX rotor is on 0º.
What is the angular position of a TX rotor when it is pointing toward the S1 winding? (Hint.
Remember synchros are labeled counter clockwise from 0º.)
240º.
In a TDX system with standard synchro connections, the TX rotor is at 120º and the TDX rotor is at 40º. What position will the TR indicate?
80º.
What connections in a TDX system are reversed to set up the system for addition?
The S1 and S3 leads are reversed between the TX and the TDX, and the R1 and R3 leads are reversed between the TDX rotor and the TR
What connections in a TDR system are reversed to set up the system for addition?
The R1 and R3 leads between the TDR rotor and the TX to which it is connected.
What connections in a TDR system are reversed to set up the system for addition?
The R1 and R3 leads between the TDR rotor and the TX to which it is connected.
In a TDR system connected for addition in what direction will the TDR rotor field turn when the TX rotor to which it is connected turns counterclockwise?
Clockwise.
What type of synchro is used in systems requiring large amounts of power and a high degree of
accuracy?
A control synchro.
What are the three types of control synchros?
CX, CT, and CDX.
How do the CX and CDX differ from the TX and TDX?
The CX and CDX have higher impedance windings
What three things prevent a CT rotor from turning when voltages are applied to its stator windings?
The rotor is specially wound, it is never connected to an ac supply, and its output is always applied to a high-impedance load.
When a CT is on electrical zero, what is the relationship between its rotor and the S2 winding?
They are perpendicular to each other.
What is the amplitude and voltage induced into the rotor when the CX is turned 90º while the CT
remains on electrical zero?
The voltage is maximum and in phase with the ac excitation voltage to the CX.
What is the name given to the electrical output of a CT?
Error signal.
In a control synchro system, when is the output of the CT reduced to zero?
When the CX and CT rotors are in correspondence.
What is the purpose of the synchro capacitor?
To improve overall synchro system accuracy by reducing stator currents.
What type of synchros usually require the use of synchro capacitors?
TDXs, CDXs, and Cts.
What type of current is eliminated by synchro capacitors?
Magnetizing current.
How are synchro capacitors connected in a circuit?
They are delta-connected across the stator windings.
Why are synchro capacitors placed physically close to differentials transmitters and CTs?
To keep the connections as short as possible in order to maintain system.
What is the name given to the synchro system that transmits data at two different speeds?
A dual or double-speed synchro system.
What is the main reason for using a multispeed synchro system instead of a single-speed synchro
system?
Greater accuracy without the loss of self-synchronous operation.
In a dual-speed synchro system what determines the two specific speeds at which the data will be
transmitted?
The gear ratio between the two transmitters
What type of synchro system is used to transmit very large quantities?
A tri-speed synchro system.
What is the disadvantage of using a double receiver instead of two individual receivers?
If one of the receivers goes bad the entire unit must be replaced.
What is the purpose of "stickoff voltage"?
It is used in synchro systems to prevent false synchronizations
What is the reference point for alignment of all synchro units?
Electrical zero.
What is the most accurate method of zeroing a synchro?
The voltmeter method
What is the purpose of the coarse setting of a synchro?
It ensures the synchro is on 0º, not 180º.
When is a synchro receiver (TR) properly zeroed?
TR is zeroed when electrical zero voltages exist across its stator windings at the same time its rotor is on zero or on its mechanical reference position
What should a voltmeter read when a TX is set on coarse zero?
Approximately 37 volts.
What precaution should you take when you use 115 volts to zero a differential?
Never leave the circuit energized for more than 2 minutes.
Why should a synchro be rechecked for zero after it is clamped down?
To ensure that it did not move off zero while it was being clamped.
What is the output voltage of a CT when it is set on electrical zero?
Zero or minimum voltage.
When you zero a multispeed synchro system which synchro should you zero first?
The coarse synchro.
What method of zeroing a synchro is perhaps the fastest but NOT necessarily the most accurate?
The electrical lock method.
What restrictions are placed on the use of the electrical lock method?
It can be used only if the leads of the synchro are accessible and the rotor is free to turn.
When you zero a synchro with a synchro tester, what is indicated by a jump in the synchro tester's
dial when the S1 and S3 leads are momentarily shorted?
The synchro under test is not on electrical zero.
What should you do with a synchro that has a bad set of bearings?
Replace it.
Name two types of trouble you would expect to find in a newly installed synchro system.
Improper wiring and misalignment.
What type of indicator is usually placed in the stator circuit of a torque synchro system?
An overload indicator
What is the most probable cause of trouble in a synchro system that has all of its receivers
reading incorrectly?
The transmitter or main bus.
If an ac voltmeter is connected between the S2 and S3 windings on a TX, at what two rotor
positions should the voltmeter read maximum voltage?
150º and 330º
What precaution should you take when substituting a synchro tester in a circuit for a transmitter?
Use only one receiver so as not to overload the tester.
What two characteristics of IC synchros cause them to differ from standard synchros?
Direction of rotation and amount of torque.
Compare the power sources of synchros and step-transmission systems.
Synchros use ac; step transmission uses dc.
A step transmitter is a modification of what electrical device?
Rotary switch.
What type of mathematical problem is solved by resolvers?
Right-triangle, or trigonometric, problems.
—A servo system that controls the acceleration (rate of
change in velocity) of a load.
ACCELERATION SERVO SYSTEM
—A device that measures acceleration to which it is subjected and
develops a signal proportional to it.
ACCELEROMETER
—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.
ANGULAR POSITION
—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 DRIFT
—The range of frequencies a servo amplifier can amplify without causing
unacceptable distortion to the input signal.
BANDWIDTH
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 DIFFERENTIAL TRANSMITTER (CDX)—
—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 SYNCHRO SYSTEMS
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.
CONTROL TRANSFORMER (CT)
A type of synchro that converts a mechanical input,
which is the angular position of its rotor, into an electrical output signal. The output is taken from the stator windings and is used to drive either a CDX or CT
CONTROL TRANSMITTER (CX)
The term given to the positions of the rotors of a synchro transmitter
and a synchro receiver when both rotors are on 0 or displaced from 0 by the same angle
CORRESPONDENCE
A mechanical or electrical technique used in synchro receivers to prevent the rotor from oscillating or spinning. Damping is also used in servo systems to minimize overshoot
of the load.
DAMPING
The number of axes about which a gyro is free to precess.
DEGREE-OF-FREEDOM
A circuit used in servo systems to convert an ac signal to a dc signal. The
magnitude of the dc output is determined by the magnitude of the ac input signal, and its
polarity is determined by whether the ac input signal is in or out of phase with the ac reference voltage.
DEMODULATOR
A synchro zeroing method. This method is used only when the rotors of the synchros to be zeroed are free to turn and their leads are accessible.
ELECTRICAL-LOCK
A standard synchro position, with a definite set of stator voltages, that is used as the reference point for alignment of all synchro units.
ELECTRICAL ZERO
The positioning of a gyro into a desired position and the maintaining of that position.
ERECTING (A GYRO)
The component in a servo system that determines when the load has
deviated from its ordered position, velocity, etc.
ERROR DETECTOR
The name commonly given to the servo motor in a servo system. So named because it reduces the error signal by providing feedback to the error detector.
ERROR REDUCER
—In servo systems, the signal whose amplitude and polarity or phase are used
to correct the alignment between the controlling and the controlled element. It is also the name given to the electrical output of a control transformer (CT).
ERROR SIGNAL
A mechanical frame, with two perpendicular, intersecting axes of rotation, used to
support and furnish a gyro wheel with the necessary freedom to tilt in any direction.
GIMBAL
A mechanical device containing a spinning mass mounted so that it can assume
any position in space.
GYROSCOPE
—Electromechanical devices, used to transmit information, that operate on the same principles of interacting magnetic fields as synchros, but differ in their direction of rotation and the amount of torque obtainable. Because of their construction, they are
sometimes called reversed synchros.
IC SYNCHROS
The physical tendency of a body in motion to remain in motion and a body at rest to remain at rest unless acted upon by an outside force (Newton's First Law of Motion).
INERTIA
—An electromagnetic device that uses one or more saturable reactors to obtain a large power gain. This device is used in servo systems requiring large amounts of power to move heavy loads.
MAGNETIC AMPLIFIER
—A circuit used in servo systems to convert a dc signal to an ac signal. The
output ac signal is a sine wave at the frequency of the ac reference voltage. The amplitude of
the output is directly related to the amplitude of the dc input.
MODULATOR
A servo system that contains more than one servo loop,
each loop designed to perform its own function
MULTI-LOOP SERVO SYSTEM—
NEWTON’S SECOND LAW OF MOTION—
If an unbalanced outside force acts on a body,
the resulting acceleration is directly proportional to the magnitude of the force, is in the direction of the force, and is inversely proportional to the mass of the body.
—A component in a servo system that measures position and converts the measurement into a form convenient for transmission as a feedback signal.
POSITION SENSOR
The rotation of the spin axis of a gyro in response to an applied force. The direction of precession is always perpendicular to the direction of applied force.
PRECESSION
The magnetic field produced in a synchro by the
combined effects of the three stator magnetic fields.
RESULTANT MAGNETIC FIELD—
The tendency of the spin axis of a gyro wheel to remain in a fixed direction in
space if no force is applied to it.
RIGIDITY
The rotating member of a synchro that consists of one or more coils of wire wound on
a laminated core. Depending on the type of synchro, the rotor functions similar to the
primary or secondary winding of a transformer. In a gyro, the rotating member is sometimes called a gyro wheel.
ROTOR—
—The term used to describe the use of unequal resistors in a servo's summing network to compensate for differences between input and output signal levels.
SCALING FACTOR
—An ac or dc amplifier used in servo systems to build up signal strength. These amplifiers usually have relatively flat gain versus frequency response, minimum phase shift, low output impedance, and low noise level. The dc amplifier is subject to excessive
drift and is relatively unstable.
SERVO AMPLIFIER
—An ac or dc motor used in servo systems to move a load to a desired
position or at a desired speed. The ac motor is usually used to drive light loads at a constant
speed, while the dc motor is used to drive heavy loads at varying speeds.
SERVO MOTOR
—In a gyro, a vector representing the angular velocity of the gyro rotor. The spin vector lies along the spin axis of the rotor.
SPIN VECTOR
The stationary member of a synchro that consists of a cylindrical structure of slotted laminations on which three Y-connected coils are wound with their axes 120 apart.
STATOR
—A low voltage used in multispeed synchro systems to prevent false synchronizations.
STICKOFF VOLTAGE
A combination of two or more parallel resistors used in servo systems as error detectors. The output of the network is the algebraic sum of the inputs.
SUMMING NETWORK
A small motorlike device that operates like a variable transformer and is used primarily for the rapid and accurate transmission of data among equipments and stations.
SYNCHRO
A unit containing three delta-connected capacitors. The synchro capacitor is used in synchro systems to increase the system's accuracy by cancelling or reducing phase shift introduced by synchro inductance
SYNCHRO CAPACITOR
A synchro receiver with a calibrated dial. This receiver is used primarily for locating defective synchros. It can also be used for zeroing synchros.
SYNCHRO TESTER
—A circuit used in servo systems, also called a crossover or switching network, to sense how far the load is from the point of correspondence and then
functions to switch the appropriate signal into control.
SYNCHRONIZING NETWORK
A small ac or dc generator, sometimes referred to as a rate generator, which
converts its shaft speed into an electrical output.
TACHOMETER
The delay in a servo system between the application of the input signal and the actual movement of the load.
TIME LAG
—A measure of how much load a machine can turn. This measurement is expressed
either in ounce-inches for torque synchro systems or in pound-feet for heavy machinery
TORQUE
A type of differential synchro that takes
two electrical inputs, one to the rotor and one to the stator, and produces a mechanical
output. The output is the angular position of the rotor, which represents the algebraic sum or
difference of the two electrical inputs
TORQUE DIFFERENTIAL RECEIVER (TDR)
—A synchro system containing either a TDX or a TDR. This system is used in application where it is necessary to compare two
signals, add or subtract the signals, and furnish an output proportional to the sum or difference between the two signals.
TORQUE DIFFERENTIAL SYNCHRO SYSTEM
A synchro that is functionally the same as the CDX except that it is used in torque systems rather than control systems.
TORQUE DIFFERENTIAL TRANSMITTER (TDX)
A type of synchro that converts the electrical input supplied to
its stator back to a mechanical angular output through the movement of its rotor.
TORQUE RECEIVER (TR)
A synchro that is functionally the same as the CX except that it is used in torque synchro systems.
TORQUE TRANSMITTER (TX)—
In a gyro, a vector representing the rotary motion applied to change the direction of the rotor axis.
TORQUE VECTOR
A servo system that controls the speed of the load it is
driving.
VELOCITY SERVO SYSTEM
X-AXIS—
In a gyro, the spin axis of the gyro
Y-AXIS—
In a gyro, an axis through the center of gravity and perpendicular to the spin axis.
Z-AXIS—.
In a gyro, an axis through the center of gravity and mutually perpendicular to both the spin (X) and Y axes
The process of adjusting a synchro to its electrical zero position.
ZEROING