Electrical 10
In a compound DC motor control circuit, the field loss relay will disconnect the ___ if power is lost to the ___
armature, shunt field
In a series DC generator, if load is added, the current flow ___ and the output voltage ___
increases, increases
In a DC generator, the three main basic typs of armature windings are the
lap-wound, the wire-wound and the frog leg-wound
What tool is commonly used to set the neutral plane of a DC generator?
AC Voltmeter
T/F It is all right to operate series motor with no load connected
FALSE
The servomotor which has a fiberglass and copper rotor is the ___ motor
ServoDisc
In a DC generator, when more loops of wire are used in the armature, this results in less ripple of the rectified voltage
TRUE
The cumulative compound motor connection means that the fields of the series and shunt field windings
add
Armature reaction is the bending of the line of flux between the pole pieces by the magnetic field produced around the
armature
Countertorque is caused by the magnetic attraction between the field pole pieces and the ___ magnetic field
armature
When the series and shunt field windings of a DC compound generator are connected so they aid each other in the production of magnetism, this is called a ___ compound
cumulative
The compound motor connection that is rarely used is the
differential
In a DC machine, series filed winding are made with relatively ___ turns of ___ wire
few, large
In a DC generator, armatures are wound to provide high voltage, high current, or some specific combination of voltage and current. Which winding type provides moderate voltage and moderate current?
frogleg
In a DC generator, what devices provide the magnetic field necessary for the operation of the machine?
pole pieces
What is the purpose of an equalizer connection in paralleled DC generators?
prevents the motoring of one machine
Because the rotor of a ServoDisc motor is made from copper laminated onto a fiberglass disk, the motor is also called a ___ motor
printed circuit
Some DC servomotors have square wave input voltage. To vary the motor speed, the on and off time ratio of the square wave is varied. This is called ___ modulation
pulse-width
The excitation in a self-excited shunt generator comes from
residual magnetism in the pole pieces
Torque is a force that tends to cause
rotation
In a series-connected DC generator, the field is generated from
self-excitation
A compound motor has ___ field windings
series and shunt
In a DC generator, voltage regulation is determined by the resistance of the armature. A generator with good voltage regulation has a(n) ___ amount of voltage drop as load is added
small
A force that tends to cause rotation is known as
torque
Permanent magnet motors have ___ efficiency than wound field motors
higher
In a DC generator, armatures are wound to provide high voltage, high current, or some specific combination of voltage and current. Which winding type provides high voltage and low current?
wave
Counter-electromotive force (CEMF) and back-EMF are names for the voltage induced into the armature of a DC motor
TRUE
T/F In a DC generator, to increase the amount of output voltage, it is common practice to increae the number of turns of wire for each loop
TRUE
In a DC generator, the rotating member of the machine is called the
armature
The speed regulation of a DC motor is proportional to the
armature resistance
What device, which rides against the commutator segments, carries the power to the outside circuit?
brush
What devices ride against the commutator segments to make an electrical connection to the external circuit of the DC generator?
brushes
The motor that does not contain a wound armature, commutator, or brushes is the ___ motor
brushless DC
In a separated excited DC shunt generator, how is the output voltage controlled?
by varying the field excitation current
In a DC generator, alternating voltage produced in the armature is converted into direct voltage before it leaves the generator by the
commutator
A DC generator containing both series and shunt field windings is called a ___ generator
compound
In a DC compound generator, the relationship of the strength between the series field and the shunt field windings determines the amount of
compounding
A device that converts mechanical energy into electric energy in the form of DC is called a(n)
generator
In a DC generator, armatures are wound to provide high voltage, high current, or some specific combination of voltage and current. Which winding type provides low voltage and high current?
lap
DC generators operate on the principle of ___ induciton
magnetic
A DC generator that uses permanent magnets as its field is commonly referred to as a
magneto
In a DC machine, shunt field windings are made with ___ turns of ___ wire
many, small
A device that converts electrical input into mechanical output is called
motor
Small permanent magnet motors that have lightweight rotors are often used as
servomotors
The DC 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
T/F When the windings in a DC generator are perpendicular to the lines of flux, and maximum induced voltage is being created, this is usually called the neutral plane
FALSE
In a DC compound generator, the series field diverter is also called the
series field shunt rheostat
