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76 Cards in this Set
- Front
- Back
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What is the name given to a variety of rotary electromechanical, position sensing device? |
The synchro |
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What is the primary purpose of a synchro system? |
Precise and rapid transmission of data betwen equipment and stations |
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Name the two general classifications of synchro systems? |
Torque and control
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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
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What two synchros provide a mechanical output? |
The torque receiver (TR) and the torque differential receiver (TDR)
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What does the code 26V-11TX4D mean on a synchro nameplate? |
It is the third modification of a 26 volt 400 hertz (torque) synchro transmitter whose body diameter is between 1.01 and 1.10 inches
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Which of the two synchro designation codes is indicated by 5DG on a synchro nameplate? |
The Navy prestandard designation code
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On the synchro schematic symbol, what indicates the angular displacement of the rotor? |
The position of the arrow
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What are the two major components of a synchro? |
The rotor and the stator
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Which of the two main types of rotors can have either a single winding or three Y connected windings? |
The drum or wound rotor
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How does the stator receive its voltage? |
By the magnetic coupling from the rotor |
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Where are the external connections made on a standard synchros? |
At the terminal board
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What major factors determine the load capacity of a torque synchro transmitter? |
The number and type of synchro receivers, the mechanical loads on these receivers and the operating temperatures of both the transmitter and receivers
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Define the term torque? |
A measure of how much load a machine can turn
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What unit of measurement refers to the torque of a synchro transmitter? |
Ounce-inches
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What type of equipment normally uses 26 volts 400 hertz synchro? |
Aircraft
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When will a synchro generate more heat than it is designed to handle? |
When it is overloaded
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How do synchros differ from conventional transformers? |
Synchros have one primary winding that can be turned through 360 degrees and three secondary windings spaced 120 degrees apart
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Describe the zero position of a synchro transmitter. |
The transmitter is in its zero position when the rotor is aligned with the S2 stator windings
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When is the maximum voltage induced into a stator coil? |
When the rotor coil is aligned with the stator coil
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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
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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
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What method is used to prevent oscillations in large synchro units? |
Mechanical damping
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What two components make up a simple synchro transmission system? |
A synchro transmitter and a syncro receiver
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What leads in a simple synchro system are connected to the ac power line? |
The rotor leads
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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 |
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What is the name given to the angle through which a transmitters rotor is mechanically rotated? |
Signal
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What two receiver leads are reversed to reverse the rotor's direction of rotation? |
1 and S3
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What is the most likely problem if the transmitter shaft reads 0 degree when the receiver shaft indicates 180 degrees? |
The rotor leads on either the transmitter or the receiver are reversed
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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 subtractions functions |
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What are the two types of differential synchros? |
The TDX and the TDR
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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
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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
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In a TDX system when does the TR rotor follow the TX rotor exactly? |
When the TDX rotor is on 0 degree
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What is the angular position of a TX rotor when it is pointing toward the S1 winding? |
240 degrees
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In a TDX system with standard synchro connections, the TX rotor is at 120 degrees and the TDX rotor is at 40 degrees. What position will the TR indicate? |
80 degrees
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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
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What connections in a TDR syste are reversed to set up the system for addition? |
The R1 and R3 leads between the TDR rotor and the TX to which is is connected
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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
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What type of synchro is used in systems requiring large amounts of power and a high degree of accuracy? |
A control synchro
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What are the three types of control synchros? |
CX, CT, and CDX
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How do the CX and CDX differ from the TX and TDX? |
The CX and CDX have higher impedance windings
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What three things prevent a CT rotor from turning when voltages are applied to is 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
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When a CT is on electrical zero, what is the relationship between its rotor and the S2 winding? |
They are perpendicular to each other
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What is the amplitude and voltage induced into the rotor when the CX is turned 90 degrees while the CT remains on electrical zero? |
The voltage is maximum and in phase with the ac excitation voltage to the CX
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What is the name given to the electrical output of a CT? |
Error signal |
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In a control synchro system, when is the output of the CT reduced to zero? |
When the CX and CT rotors are in correspondence
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What is the purpose of the synchro capacitor? |
To improve overall synchro system accuracy by reducing stator currents
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What type of synchros usually require the use of synchro capacitors? |
TDXs, CDXs, and CTs
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What type of current is eliminated by synchro capacitors? |
Magnetizing current
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How are synchro capacitors connected in a circuit? |
The are delta connected across the stator windings
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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
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What is the name given to the synchro system that transmits data at two different speeds? |
A dual or double speed synchro system |
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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
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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 transmitter
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What type of synchro system is used to transmit very large quantities? |
A tri-speed synchro system
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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
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What is the purpose of stickoff voltage? |
It is used in synchro systems to prevent false synchronizations
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What is the reference point for alignment of all synchro units? |
Electrical zero
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What is the most accurate methods of zeroing a synchro? |
The voltmeter method
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What is the purpose of the coarse setting of a synchro? |
It ensures the synchro is on 0 degree, not 180 degree |
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When is a synchro receiver (TR) properly zeroed? |
A 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
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What should a voltmeter read when a TX is set on coarse zero? |
Approximately 37 volts
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What precaution should you take when you use 115 volts to zero a differential? |
Never leave the circuit energized for more than 2 minutes
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Why should a synchro be reached for zero after it is clamped down? |
To ensure that it did not move off zero while it was being clamped
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What is the output voltage of a CT when it is set on electrical zero? |
Zero or minimum voltage
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When you zero a multispeed synchro system which synchro should you zero first? |
The coarse synchro
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What method of zeroing a synchro is perhaps the fastest but NOT necessarily the most accurate? |
The electrical lock method
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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
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When you zero a synchro with a synchro testerm what is indicated by a jump in the synchro teser's dial when the S1 and S3 leads are momentarily shorted? |
The synchro under test is not on electrical zero
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What should you do with a synchro that has a bad set of bearings? |
Replace it
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Name two types of trouble you would expect to find in a newly installed synchro system? |
Improper wiring and misalignment
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What type of indicator is usually placed in the stator circuit of a torque synchro system? |
An overload indicator
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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 |
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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? |
150 degrees and 330 degrees
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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 |
