Motors and Transformers Final
Shunt generators contain only a shunt field winding connected in _____ with the armature.
parallel
A compound motor has _____ field windings.
Series and shunt
The non-rotating part of an alternator is called the
stator
A ___ is used to measure the difference in voltage and frequency between two alternators
synchronoscope
In a 3-phase motor, the speed of rotation of the magnetic field is called the ___ speed.
synchronous
A synchromotor operated with no load and used for power factor correction is sometimes called a ____.
synchronous condensor
The pushing or turning force created by the magnetic field of the pole pieces and the magnetic field of the loop or armature is called ___
torque
Counter Electromotive Force (CEMF) and Back-EMF are names for the voltage induced into the armature of a d/c motor
true
The compound motor connection that should generally be avoided is the ___
differential
Compound generator both series and shunt that oppose each other
differential - compound
The direct current that is an output to the alternator's rotor is the ___ current
excitation
A series motor may be operated with no load connected.
false
The synchronous motor is an induction motor
false
series field windings are wound with ____ turns of fairly ____ wire.
few / large
The higher power output alternators use a revolving _____.
field
Using a ___ is a method of preventing induced voltage from becoming excessive.
field discharge resistor
The output voltage of a generator is usually controlled by the amount of ____
field excitation current
Armature winding wound for moderate voltage and moderate current
frogleg-wound
What is a device that converts mechanical energy into d/c electrical energy?
generator
The wound rotor inductor motor is popular in industry because it has ____ starting torque and ____ starting current.
high / low
Permanent magnet motors have ____ efficiently than conventional field-wound motors
higher
In order to increase the efficiency of the cooling, some alternators operate in an atmosphere of ____
hydrogen
Armature winding wound for low voltage and high current
lap-wound
The revolving armature type alternator is capable of _____ power output and is, therefore, _____ often used than the revolving field type.
less / less
shunt field windings are wound with ____ turns of fairly ____ wire.
many / small
a device that converts electrical energy into mechanical energy
motor
The rotating part of an alternator is called the
rotor
Some motors are constructed so that they will operate on either of two voltages. When they are connected to operate on the higher of two voltages, the windings are connected in ___
series
The series generator has only a series field, which is connected in ____ with the armature.
series
In a generator, the _____ permits part of the current that normally flows through the series field to flow through the resistor.
series field shunt rheostat
The servomotor featuring a fiberglass and copper rotor is the ____ motor
servodisc
Small permanent magnet motors that have lightweight rotors are often used as _____.
servomotors
The squirrel cage rotor code letters indicate the shape (type) of the rotor bars. Different types of bars have a large effect on the ___ of a motor.
starting torque
Armature winding wound for high voltage and low current
wave-wound
The torque of a squirrel-cage induction motor will be maximum when the phase angle between the stator and rotor fields is ___
zero degrees
Because some of the input energy to the alternator ends up being converted into heat, often cooling is required. The main types of cooling media are ____
air and hydrogen
_____ operate on the same principle of electromagnetic induction as DC generators, but they have no commutator.
alternators
The set of squirrel cage bars on the rotor of a synchronous motor is used to start the motor and is known as the ____.
amortisseur winding
To reverse the direction of rotation of a 3-phase motor, reverse ___
any two leads
The rotating part of a generator is called the ____
armature
In a compound D/C motor control circuit, the field loss relay will disconnect the ____ if power is lost to the ____
armature / shunt field
___ is the twisting or bending of the magnetic lines of flux of the pole pieces
armature reaction
The speed regulation of a d/c motor is proportional to the ____
armature resistance
The squirrel-cage rotor is constructed of ___ and end ___ embedded in steel laminations
bars / rings
The ____ ride against the commutator segments and are used to connect the armature to the external circuit of the d/c machine.
brushes
The motor that does not contain a wound armature, commutator, or brushes is the ____.
brushless d/c
When a squirrel-cage motor is first started, the value of the current draw is ___
several times the running current
The D/C motor, known as a "constant speed motor" is the ____ motor
shunt
When the field winding of a DC motor is connected in parallel with the armature, the motor is called a _____ motor.
shunt
When a motor is connected differential compound, the _____ determines the direction of rotation of the motor at no load or light load.
shunt field
Selsyn motors operate on ___ voltage.
single phase
Three lines supply power to a three-phase motor. If one of these lines should open, the motor will be connected to single-phase power. This condition is known as _____.
single phasing
Connection to the armature of an alternator is normally done using ____
sliprings
For most squirrel-cage induction motors the typical percent slip is about _____ percent.
two to five
A motor is operating at 3450 RPM and is producing a torque of 32 lb-in. What is the output horsepower of the motor?
1.75 HP
An alternator containing eight poles per phase is turning at 1500 RPM. What is the output frequency?
100 Hz
The differential selsyn has 3 stator windings connected in wye and a rotor made of ____ .
3 windings connected in wye
A motor has a synchronous speed of 3600 RPM and an actual rotor speed of 3450 RPM. What is the percentage slip?
4.17%
The output frequency of an alternator is controlled by the ___
number of stator polls and rotor rotation speed
An alternator containing eight poles per phase is turning at 900 RPM. What is the output frequency?
60 Hz
A 3-phase alternator containing eight poles per phase is turning at 900 RPM. What is the output frequency?
60 Hz
The servodisc motor is often called a ____ motor.
printed-circuit
The speed of the disc servomotor can be varied by changing the amount of voltage supplied to the armature. The voltage is generally varied using ___.
pulse-width
An alternator that uses a separate small alternator mounted on the shaft of its motor is equipped with a ____
brushless excitor
What is the component of a d/c generator that converts the armature a/c to d/c?
commutator
When a d/c machine is used as a generator, the ____ performs the function of a mechanical rectifier to change the a/c produced in the armature into d/c before it exits the machine thru the brushes.
commutator
Generator that is both series and shunt
compound generator
The relationship of the strengths of the two fields in a generator determines the amount of _____
compounding
___ is a measure of useful electric energy produced by the generator
countertorque
Compound generator both series and shunt that aid each other
cumulative - compound
In the consequent pole motor, if the number of poles is doubled, the motor speed will be ___.
cut in half
Frequency of the current in the rotor ___ as the rotor approaches synchronous speed.
decreases
If one alternator does not produce sufficient power to supply a load, another alternator can be connected to the circuit. The second alternator is connected in _____.
parallel
Some motors are constructed so that they will operate on either of two voltages. When they are connected to operate on the lower of the two voltages, the windings are connected in ___
parallel
The direction of magnetic field rotation is known as ___ rotation
phase
If a piece of machinery needs a replacement motor and will be damaged if the new motor rotates the wrong way, the test equipment needed to test the rotation direction fo the new motor is a ___
phase rotation meter
What provides the magnetic field necessary for the operation of a d/c machine?
pole pieces
