AC/DC Machines Test 1

The speed of the disc servo motor can be varied by changing the amount of voltage supplied to the Armature the voltage is generally varied using?

Pulse width modulation

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 servo motor which has a fiberglass and copper rotor is?

Servo disc motor

Small permanent magnet motors have lightweight rotors that are often used as?

Servo motors

When a motor is connected differential compound the __________determines the direction of rotation of the motor at no load or light load

Shunt field

The DC motor known as a constant speed motor is?

Shunt motor

If current is flowing in a circuit containing an inductor in the Place which is open the magnetic field surrounding the inductor collapses and induces voltage into the inductor resulting in a voltage spike

True

The amount of voltage induced into a conductor depends on the terms of wires the strength of the magnetic field and the speed of the cutting action

True

A ____________ may occur when current flows through an inductor, stops, and the current also decreases at an exponential rate

Voltage spike

Armatures are wound to provide high voltage high current or some specific combination of voltage and current the winding that provides high voltage and low current is

Wave wound

The magnetic quantity weber is equal to 100,000,000 lines of flux if a conductor cuts through one weber per second in a voltage of _________ is induced into the conductor

1v

When a conductor cuts magnetic lines of force a voltage is induced into the conductor this principle is called?

Electromagnetic induction

A series motor may be operated with no load connected

False

The unit of inductance is the

Henry

An induced voltage opposes the motion that caused it according to

Lenz's law

A force that tends to cause rotation is known as?

Torque

Counter electro motive force and back EMF our names for voltage induced into the Armature of a DC motor

True

The rotating part of a generator is called

armature

The _______ ride against the commutator segments and are used to connect the armature to the external circuit of the Dc machine

brushes

The ___________ describes the rate of certain occurrences

exponential curve

One device used for spike suppression in either direct or alternating current circuits is the _____ _____ _____.

metal oxide varistor (MOV)

A device that converts electrical energy into mechanical energy is called?

motor

When using the left hand generator rule the thumb points to the direction of?

thrust

Inductors always _________ a change of current

Oppose

If a conductor is moved upward the polarity of induced voltage is reversed in the current flows in the __________ direction

Opposite

Shunt generators contain only a shunt field winding connected in ________ with the Armature

Parallel

During the period of time for the first time constant of exponential curve the current will rise to about _______ of its full value

63.2%

The twisting or bending of the magnetic lines of flux of the pole pieces

Armature reaction

The speed regulation of a DC motor is proportional to the?

Armature resistance

In a compound DC motor control circuit the field lost relay will disconnect the ________ if power is lost to the __________

Armature, Shunt field

The motor that does not contain a wound Armature commutator or brushes is the?

Brushless Dc motor

The component of a DC generator that converts the Armature AC into DC is

Commutator

When a DC machine is used as a generator the _________ performs the function of a mechanical rectifier to change AC produced in the Armature into DC before it exits the machine through the brushes

Commutator

A generator containing both series and shunt fields is called

Compound generator

The relationship of the strengths of two fields in a generator determines the amount of

Compounding

A measure of useful electric energy produced by a generator

Counter torque

A compound generator has both series and shunt field windings and when they are connected they aid each other in production of magnetism and that connection is called?

Cumulative compound

When using the left hand generator rule the center finger points to the direction of

Current

A device that converts mechanical energy into DC electrical energy

Dc generator

Shunt field windings are connected in parallel with the armature. They are wound with _____ turns of fairly _____ wire.

Many, small

The magnetic field necessary for the operation of the machine

Pole pieces

The time required for current in an inductor to reach its full ohms law value is called the

R-L Constant

A compound motor has what field windings?

Series and shunt field windings

When a close loop of wire cuts through magnetic flux lines they current is induced into the loop the current in the loop set up a magnetic field that is in opposition to the original magnetic flux this is essentially

Lenz's Law

A compound generator has both series and shunt field windings when those windings are connected so their fields oppose each other in the production of magnetism that connection is called?

Differential compound

The compound motor connection that should generally be avoided is?

Differential compound

Losses in the core of iron core inductors include _________ and _________?

Eddy current, hysteresis

Series field windings are connected in series with the Armature they are wound with ______ turns of fairly ______ large wire

Few, large

The output voltage of the generator is usually controlled by the amount of

Field excitation current

The direction of induced current can be determined by using the _____ left-hand generator rule.

Fleming's

Armatures are wound To provide high-voltage high current or some specific combination of voltage and current the winding that provides moderate voltage and moderate current is

Frog leg wound

Permanent magnet motors have _______ efficiency than conventional field wound motors

Higher

Armatures are wound to provide high voltage high current or some specific combination of voltage and current the wiring that provides low-voltage in the high current is

Lap wound

A way of determining the relationship of the motion of the conductor, the magnetic field direction, and the direction of induced current is by using the?

Left hand generator rule

If a voltage is being induced into a conductor by electromagnetic induction reversing the direction of motion of the conductor will?

reverse the polarity of the induced voltage

The series generator has only a series field which is connected in ________ with the armature

series

When the field winding of a DC motor is connected in parallel with the Armature the motor is called a ________ motor

shunt