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77 Cards in this Set
- Front
- Back
As motor load is increased, what decreases? |
RPM |
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how is the start winding of an AC induction motor disconnected from the circuit? |
with a centrifugal switch |
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an AC motor produces maximum output torque _____ |
just before locked rotor |
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stator field rotation is also called ______ |
synchronous speed |
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which of the following defines synchronous speed? (N = Pole Pairs) |
60*f/n |
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Rotor rotational speed is also called ________ |
shaft speed |
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what is slip speed |
synchronous speed - shaft speed |
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an AC motor is typically described as a one-, two-, or three-_____ motor |
phase |
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CEMF and speed are ______ |
proportional |
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1 horsepower is the power rate corresponding to _______ |
33000 ft*lb/s |
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what are the 2 basic components of a motor |
poles and armature |
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what best describes torque? |
a twisting action |
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As CEMF increases, what happens to conductor speed and torque? |
speed increases, torque decreases |
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100% efficiency means the _______ |
input power equals the output power |
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if a motor is supplied 2500 watts of electrical energy, how much horsepower would it supply |
3.35 hp |
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if a motor is producing 1.5 hp, how much electrical power is it absorbing? (assume no internal loss) |
1119 W |
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inefficiency means the _______ |
input is much greater than the output |
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electrical power is defined in terms of _________ |
watts |
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Speed and torque are _________ |
inversely proportional |
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efficiency is measured as a _______ |
percent |
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what is motor efficiency? |
Ratio of output power to input power. |
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what is the efficiency rating of a theoretically "perfect" rotating machine |
100% |
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what does CEMF stand for? |
Counter Electromotive Force |
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when is torque maximum? |
locked condition. |
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CEMF opposes the ___________ |
applied voltage and original conductor magnetic field |
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1 hp equals how many watts? |
746 w |
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mechanical power is defined in terms of ________ |
horsepower |
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what is the major difference between the torque synchro system and the control synchro system? |
the control system provides drive signals for a servo system |
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how is positional reference derived in a control synchro system |
mechanically coupled to the CT |
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control synchro systems provide high current to rotate radars |
false |
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which device in the control synchro system performs the same function as the torque transmitter? |
control transmitter |
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when synchronized, what is the output from a control transformer? |
out of phase |
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what is a control differential trasmitter? |
CDX |
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how does a control transolver differ from a control transformer? |
the control transolver has an additional rotor winding |
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what principle of magnetism do generators operate on? |
attraction and repulsion |
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how is pulsating DC output eliminated in DC generators |
using a multiple-loop armature |
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what part of a motor allows reversing the magnetic poles in the rotor? |
comutator and brushes |
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what principle of magnetism allows the use of electromagnetic stators |
passing a current through a conductor produces a magnet |
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in a motor it is important to know that the starting current _________ |
is higher than the running current |
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in the motor's voltage source circuit, what is the purpose of U1 |
difference amplifier |
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in a generator, when the armature rotation is parallel to the stator magnetic field, what is the output voltage? |
zero |
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what principle of magnetism allows a generator to power its own windings and still generate an output voltage? |
retentitivity |
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during troubleshooting of a motor-generator set, if the set is not rotating, what is the probable faulted area? |
motor and motor circuits |
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A TR synchro is a torque _________ |
receiver |
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A TX synchro is a torque ________ |
transmitter |
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Two basic components of a synchro are the staor and the ________ |
rotor |
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the mechanical movement of a synchro produces a voltage that represents _________ |
angular information |
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the rotor in a synchro ________ |
is a rotable winding |
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A CT synchro is a control _______ |
transolver |
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the 2 classifications of synchros are control synchros and ___________ |
torque synchros |
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the purpose of a synchro system is to transfer |
angular information |
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in an F/V converter, the ration between the input and the output voltage is known as the _______ |
conversion factor |
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the most common motion detectors convert motion into ______ |
frequency |
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What is the relationship between distance and time when solving for velocity (V) |
(change)D/(change)T |
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if the number of sensing holes were doubled from 16 to 32, for a given rpm, the pulse train _______ |
Tcycle would decrease to 1/2 |
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an rpm detector circuit with an F/V converter chip uses a dis with 100 marks/revolution and has a conversion factor of 2v/khz. each 0.2 volts of the chip represents ________ rpm |
60 |
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what are the 2 principle factors of motion |
Distance and Time |
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what is motion? |
a change in distance per change in time |
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the differentiator provides an output ________ |
during acceleration and deceleration |
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for calculating the velocity of the disk holes at various rpm values, the radius to the center of the holes and the distance between the holes are used to solve for ________ |
runout rate |
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to convert rpm to rps, simply perform the following: |
rpm / 60 |
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An electrical differentiator circuit will sense a ________ voltage and disregard _______ values |
changing, absolute |
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if the sensor holes were moved closer to the center of the disk but the same number of holes were used, at a given rpm, _________ |
D is decreased so V would decrease |
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which is not a popular motion sensor used in industry |
photo inductor |
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runout rate is expressed in terms such as ________ |
feet/second |
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for measuring rpm on a spinning shaft, the distance between the sensing edges is |
unimportant |
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the ________ is the actual operating parameter or actual measured value |
process variable |
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the ________ is the optimum operating parameter, or a reference to which an operator adjusts the process for optimum operation |
set point` |
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proportional control uses an ______ as the means to increase rise time |
adjustable gain |
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what control compensates for a changing value and inhibits rapid changes in the output value? |
derivitive |
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the _______ control reaches the set point value but degrades rise time |
PI |
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which control system provides a fast rise time, minimal overshoot, and quick response to outside influences? |
PID |
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which control system provides the poorest performances? |
P |
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the _______ control reduces overshoot |
PD |
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what is the condition which indicates that the values of a circuit have settled and tend to remain constant? |
steady-state |
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stabilization is reached as the _______ reduces the overshoot of the signal. |
proportional control mode |
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l |