ATT Test 11 (Latest 2024/ 2025 Update) Questions and Verified Answers| 100% Correct| Grade A

ATT Test 11 (Latest 2024/ 2025 Update)
Questions and Verified Answers| 100%
Correct| Grade A
Q: What characteristic is a twisting force that causes shaft to rotate?
Answer:
Torque
Q: How is torque calculated in generators?
Answer:
Force X Distance from center of shaft
Q: How are torque and speed related?
Answer:
Inversely proportional
Q: What characteristic is a generated voltage that OPPOSES applied volts?
Answer:
Couterelectromotive Force (CEMF)
Q: How is CEMF produced?
Answer:

By the rotation of motors shaft
Q: How is CEMF related to speed and torque?
Answer:
CEMF is proportional to speed and inversely proportional to torque
Q: What are loads?
Answer:
items that require motion and are driven by rotating shaft (motors) and electrical circuits that
require power (generators)
Q: How are loads related to speed?
Answer:
Inversely proportional
Q: What characteristic is the amount of work accomplished?
Answer:
power
Q: How is power calculated in motors?
Answer:
torque X RPM X K

Q: How is power measured?
Answer:
Watts and HP
Q: How is power related to load and speed?
Answer:
Proportional to load and inversely proportional to speed
Q: When is torque greatest?
Answer:
When RPM is 0 (locked motor)
Q: How much CEMF is generated in locked motor condition?
Answer:
None
Q: What is the definition of one horsepower?
Answer:
Power needed to lift 550 lbs 1 foot in one second or (33000 lbs in one minute)
Q: What principle of magnetism do motors operate on?
Answer:
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What is a motor a device that converts electrical energy into mechanical energy
What is a generator a device that converts mechanical energy into electrical energy
What is an incremental motor a motor whose shaft rotates a specific distance in degrees
What is a continuous motor one whose shaft continuously rotates without interruption when input is applied
What type of generator produces DC volts and uses a commutator? Dynamo
Motors and generators operate on what principle? Electromagnetism
What characteristic describes how fast shaft rotates and is measured in RPM/RPS? Speed
What characteristic is a twisting force that causes shaft to rotate? Torque
How is torque calculated in generators? Force X Distance from center of shaft
How are torque and speed related? Inversely proportional
What characteristic is a generated voltage that OPPOSES applied volts? Couterelectromotive Force (CEMF)
How is CEMF produced? By the rotation of motors shaft
How is CEMF related to speed and torque? CEMF is proportional to speed and inversely proportional to torque
What are loads? items that require motion and are driven by rotating shaft (motors) and electrical circuits that require power (generators)
How are loads related to speed? Inversely proportional
What characteristic is the amount of work accomplished? power
How is power calculated in motors? torque X RPM X K
How is power measured? Watts and HP
How is power related to load and speed? Proportional to load and inversely proportional to speed
When is torque greatest? When RPM is 0 (locked motor)
How much CEMF is generated in locked motor condition? None
What is the definition of one horsepower? Power needed to lift 550 lbs 1 foot in one second or (33000 lbs in one minute)
What principle of magnetism do motors operate on? Attraction/repulsion
What are basic parts of a motor? Stator, armature (rotor), brushes, commutator, shaft
At what points are max flux lines cut and peak volts produced? When armature is parallel to lines of force (90 and 270 degrees)
What are three types of DC generators? permanent magnet, separately excited, self-excited
What are 3 types of DC motors? Series, shunt and compound
What is the assumed value of K? 1
How are speed and total current related in DC shunt field motor? Inversely proportional
What value isn’t affected by speed changes in DC shunt field motor? Field current
What are two types of speed control in DC shunt/series field motors? Armature control and shunt field control
Increasing resistance does what to speed? Decrease
Which type of DC motor has higher resistance and many turns of fine wire? Shunt motor
Which type of DC motor has lower resistance and few turns of heavy wire? Series motor
Which DC motor has more high speed torque? Shunt motor
Which DC motor has higher start current/torque? Series motor
Which DC motor has higher low speed torque? Series motor
When is armature current max? When motor is first turned on (RPM=0 CEMF=0)
Is starter current greater or lesser than running current? Greater than
What are two main factors of motion? Distance and time
How is velocity calculated? change in distance divided by change in time
What is used to measure motion? velocity
How are acceleration and deceleration calculated? change in velocity divided by change in time
Acceleration and deceleration are both changes in what? Velocity
Constant and changing velocity both equal what type of motion? Linear motion
What are two main factors of circular motion? Rotational motion and runout
What is runout? distance traveled from point on circumference in given time period
What is a measure of velocity of rotating point Runout
How is runout rate (ROR) calculated? RPM X 2R (circumference)
How is total runout distance calculated? ROR X T
Circular motion of point A will cause _ motion of plate A Linear Linear motion is equal to circular motion in terms of what? Velocity, acceleration, distance Fixed RPM causes varying ROR and ROD depending on what? Circumference In circular motion, V out is proportional to what? Acceleration What are 3 popular motion sensors? Photo interrupter, photo reflector, magnetic pickup What do position generators do? cause a change in position, use electrical input to produce mechanical output What do position sensors do? detect changes in position, use mechanical input to produce an electrical output Which position device rotates from one position to another according to digital/analog input? Position generators Which position device receives mechanical input and produces analog/digital signal output? Position sensor Define position location of object, defined in 1, 2, or 3 dimensions in respect to reference Torque and RPM depend on the of the shaft Radius
What constant is used in power calculations when HP need to be converted to FT-LBS? 9.55 (Torque X RPM)/9.55
What constant is used in power calculations when HP need to be converted to ft-lbs? 5252.5 (Torque X RPM)/5252.5
What are two types of resolvers? Induction and resistance
Resolvers use what type of motion? Circular
An induction resolver acts like which component? Transformer
Resistance resolvers are specifically designed ? Potentiometers
What are two types of digital position sensors? Increment and wheel
The shaft of which digital position sensor must return to 0 prior to each move Increment wheel
Which digital position sensor would have 4 sensors? Encoder wheel (gray or 8421)
What type of encoder wheel produces incorrect outputs during transition? How is this overcome? 8421, overcome by strobe track or using Gray code
In which speed controller does a low current control a high current motor? Relay controller
What are two types of starters? Series and parallel
A large start torque requires a start current Large
What type of controller is used in small DC motors with small currents? Solid state controllers (emitter follower)
What type of start/speed controller uses D/A converter and comparator array? Digital start/speed controller
What are two types of controllers used by DC motors? Amplitude and Time control
What are 3 types of AC motors? Universal, induction, synchronous
Which AC motor is used for large HP or special applications? Synchronous
Induction type AC motors use what kind of rotor? Squirrel cage
What induces current in the rotor (AC motor)? expanding/contracting stator mag field
What causes a magnetic field in rotor (AC motor)? Rotor current induced by stator mag field
How is slip speed calculated? Field speed minus shaft speed
What is field speed also known as (AC motors)? Synchronous speed
How is torque related to current? Proportional
Why does the rotor attempt to follow the stator? Magnetic attraction
Rotor RPM will always be than stator RPM LESS than (always lags)
How is shaft speed calculated? Field RPM minus slip RPM
“In AC motor which component is thought of as the “”primary”” and which is the “”secondary””?” Stator is primaryRotor is secondary
AC induction motor has _ start torque SMALL
What is the purpose of synchros? To transfer angular information as voltage
Define synchros rotary electromechanical position sensing devices, movement of one device produces voltage that causes movement in another device
What are two main parts of synchro? Stator and rotor
How many stators does synchro use? 3 windings in Y config
What does TX stand for? Torque transmitter
What does TDX stand for? Torque differential transmitter
What does the torque receiver do? Electronically forced to reposition in response to applied voltage (from transmitter), provides mechanical motion
What control component is similar to torque receiver? Control transformer
What are 4 steps of troubleshooting synchro systems? Confirm symptom, remove power, isolate components, locate defect
What is a multimeter used to measure when troubleshooting synchros? Ohms
What fault will cause blown fuses or tripped circuit breaker? Short rotor
What fault causes transmitter to have little effect, receivers attempt to track, and low torque? Open rotor
An open in transmitter rotor will affect one device or whole system? Whole system
What fault causes all devices to point toward good stator axis? Short stator
A short stator in receiver will affect one device or whole system? Whole system
Define gyroscope? mechanical device containing spinning mass that is universally mounted
What gyroscope principle causes wheel to remain in fixed position if no force is applied? Rigidity
What principle of gyroscopes causes spin axis to turn at right angle to angle of applied force? Precession
What factors affect rigidity? Rotor weight and speed, and rotor shape (weight distribution)
Larger diameter of rotor equals (more/less) rigidity? More
Rate of precession is proportional to what? Applied force