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