Electromagnetic Applications Miller College Missing Word
For the following questions, complete the statements on your answer sheet with the word or phrase you think fits best.
1.
When the field current in a separately excited generator is zero, the output voltage is not zero due to ________ .
2.
If the speed of the prime mover driving a generator is reduced, the output voltage will
________ .
3.
Increasing the load on a generator causes the prime mover speed to ________ due to the ________ developed by the armature current.
4.
Armature reaction is due to ________ effect which distorts the main flux, and
________ effect which weakens the main flux.
5.
Armature reaction will shift the ________ axis in the ________ direction as the direction of rotation. Magnetic neutral
6.
As the load on a generator increases, the effect of armature reaction ________ , which results in the brushes being in the ________ position for good commutation.
7.
As the load on a generator increases, the concentration of flux on the trailing edge of the pole face ________ , and the concentration of flux on the leading edge of the pole face ________ .
8.
As the load on a generator increases, the terminal voltage ________ . This is due to
________ and the ________ voltage drop.
9.
The terminal voltage of a generator is the ________ between the generated voltage and the ________ voltage drop.
10.
The open circuit characteristic of a separately excited generator shows the ________ of the magnetic material used in core.
11.
The conductors for the field system of a generator are located in the ________ .
12.
To connect the generated emf's to an external circuit, a ________ and carbon __-
______ are employed.
13.
The function of the ________ is to convert the ________ voltage generated within the armature conductors to the D.C. voltage available at the generator terminals.

Electromagnetic Applications Miller College Missing Words
14.
The generator field can be either ________ excited or ________ excited.
15.
To determine the polarity of the induced emf's within the armature conductors you would use Flemming’s ________ hand rule.
16.
Maximum emf will be induced in the armature conductors when cutting the field flux at ________ .
17.
If more turns are added to the armature conductors, the generated voltage will _____ .
18.
The emf induced into a conductor is proportional to the ________ of the magnetic field, the ________ of the conductor and the ________ of the conductor through the magnetic field.
19.
The three torques in analogue meters are the ___________ torque, which moves the needle upscale from zero, the ___________ torque, which moves the needle back to zero, and the ___________ torque, which only has an effect when the needle is
___________ .
20.
In the electrodynamometer, which measures ___________ , the ___________ coil is stationary, while the moving coil measures the ___________ in the circuit.
21.
The range of the moving ___________ meter, which is used on ___________ current circuits, may be extended using an instrument transformer.
22.
The sensitivity of a voltmeter is measured in ___________ per ___________
23.
A higher resistance ___________ meter would have a larger ___________ effect on a circuit when inserted into the circuit than a lower resistance meter
24.
A clip on DC ammeter uses the ___________ effect device to measure the
___________ produced by the current in the conductor.
25.
If two or more coils are joined by the same magnetic flux, the coils are said to be
___________ by ___________ .
26.
Two common applications employing mutual inductance are ___________ and
___________.
27.
When installing power cables and ___________ cables adjacent to each other, the cables are segregated to avoid problems associated with ___________ induced into the data cables due to ___________
28.
An LR circuit is set up when a resistor is connected in _________with an _________.

Electromagnetic Applications Miller College Missing Words
29.
Increasing the resistance of an LR circuit will cause the ________ to ___________, whilst increasing the ___________ of an LR circuit will cause the time constant to
______________.
30.
For voltages of self inductance or mutual inductance to occur, there must be
___________ between the ___________ and the ___________.
31.
If an inductive circuit is open circuited, the rapidly ___________ magnetic field can
___________ dangerously high ___________.
32.
Any circuit capable of producing magnetic ___________ has the property of
___________ .
33.
In Flemings Right Hand Rule, the thumb indicates ________; the first finger indicates
________ and the middle finger indicates ________.
34.
Most inductor cores are made from laminated _________ to reduce _________ and
_________ losses.
35.
A non-inductive coil (as used in some wire wound resistors) is produced by ______.
Accompany your answer with a diagram.
36.
To increase the inductance of a coil, you would: ( NOTE: Show as either an increase or a decrease )
(a) _________ the number of coil turns.
(b) _________ the length of the magnetic path.
(c) _________ the cross sectional area of the magnetic path.
(d) _________ the permeability of the core
37.
To increase the self induced voltage of a coil, increase either the ______ of the coil, or the _________the coil
38.
An inductor opposes ______ in current.
39.
A voltage of self inductance is an example of _________Law in action, which states
_________.
40.
When determining the voltage of self inductance of a coil, the expression
∆φ/∆ t can be stated as the ______.
41.
If the flux change linking a coil is increased, the _________ voltage will be
_________.

Electromagnetic Applications Miller College Missing Words
42.
If the rate of change of current flowing through a coil is ________the ________ voltage will decrease.
43.
For a self excited generator to build up a generated emf, there must be ________ in the magnetic circuits of the machine.
44.
Three types of self excited generators are ________ connected, ________ connected and ________ connected.
45.
A shunt connected generator will have a ________ terminal voltage at full load than at no load. This is due to the ________ effect of ________ and the ________ in the armature circuit.
46.
If a compound generator is ________ excited, the voltage at full load will be greater than the voltage at ________ .
47.
If the speed of the prime mover driving a self excited generator is ______ , then the small emf generated by ________ will not increase sufficiently to build up the required magnetic flux.
48.
The two methods of connecting a compound generator are ________ where the shunt field is connected in parallel with both the armature and the ________ , and ________ where the shunt field is in parallel with the ________ only.
49.
If a compound generator is wound as ________ compounded, then both the ________ field and shunt field fluxes will act in the same direction to assist each other.
50.
The force acting upon a current carrying conductor depends on the ________ of the magnetic field, the ________ flowing in the conductor and the ________ of the conductor within the magnetic field.
51.
The torque developed within a DC motor is proportional to the ________ acting on the conductor and the ________ of the armature.
52.
If the load applied to a DC motor is decreased, the:
(a) speed will ________,
(b) the back emf will ________,
(c) the armature current will ________ and
(d) the torque developed by the motor will ________ .
53.
The emf generated within the armature conductors ________ the applied voltage, and is known as a ________.

Electromagnetic Applications Miller College Missing Words
54.
The field system of a DC motor is mounted on the ________ and the current in the armature conductors is transferred from the supply via the ________and ________.
55.
The current flowing in the armature conductors is dependent on the ________ generated within the armature conductors.
56.
If the load applied to a DC motor is increased, the:
(a) speed will ________ ,
(b) the back emf will ________ ,
(c) the armature current will ________ and
(d) the torque developed by the motor will ________ .
57.
Motor torque is produced when the main ________ reacts with the armature _______
58.
Three methods of connecting a DC motor are _______, ________ and__________.
59.
If the load connected to a shunt connected DC motor is increased, the motor speed will __________, the back emf will __________ , the armature current will
__________, and the motor torque will __________ .
60.
A shunt connected DC motor is considered to be a __________ speed motor, and a series connected DC motor is considered to be a __________ speed motor.
61.
When unloaded, the speed of a series connected DC motor is __________ due to the
__________ field strength.
62.
Over speeding of a series connected DC motor is prevented by having a __________ connected to the motor, or by having a light __________ connected across the supply.
63.
If the load connected to a series connected DC motor is increased, the motor speed will __________, the back emf will __________ , the armature current will
__________ , and the motor torque will __________ .
64.
Series connected DC motors are commonly used for __________ and __________ .
65.
Compound connected DC motors are used for __________ speed applications where sudden changes in __________ may occur. Two examples are __________ and
__________
66.
Reversal of DOR in a DC motor is achieved by reversing the __________ connections or the __________ connections, but NOT both.

Electromagnetic Applications Miller College Missing Words
67.
If reversing the DOR of a compound motor is required, reversing the __________ connections is the simplest and preferred method as only __________ reconnection is required.
68.
A common application of shunt connected DC motors is __________ .
69.
Three methods of connecting a DC motor are _______, ________ and__________.
70.
As a DC motor accelerates up to speed the armature current _______ , back emf
_______ and torque _______.
71.
The DC shunt motor is most suited to loads requiring a relatively _______ torque at a relatively _______ speed.
72.
The speed of a motor/load combination isa constant when the motor _______ is equal to the load _______ .
73.
The speed of a DC motor _______ with increases in field flux, _______ with increases of supply voltage and _______ with increased load.
74.
The direction of rotation of a DC compound motor may be reversed by reversing the connection to the _______ or _______ the connection to the _______ field winding/s.
75.
In a DC motor the back emf is _______ than the terminal voltage and the current flows _______ the positive terminal of the armature and in the DC generator the back emf is _______ than the terminal voltage and the current flows _______ the positive terminal of the armature.
76.
In a DC generator the _______ power can be calculated using the equation V x I and the mechanical _______ power is equal to V x I _______ the machine losses.
77.
The copper loss in a motor occurs in the _______ and is due to their _______ . The iron loss is due to the _______ in the _______ core while the _______ loss is due to
_______ in bearings and brushes.
78.
The maximum efficiency of a DC motor normally occurs close to _______ load and reaches a maximum when the _______ equals the _______.
79.
Large motors generally have a _______ efficiency than small motors.
80.
High efficiency can be sustained by regular _______ of the motor and by using the motor at close to _______ load.
81.
A motor with a solid armature core would have a higher _______ loss than a similar motor with a laminated core.

Electromagnetic Applications Miller College Missing Words
82.
A motor with a hard steel armature core would have a higher _______ loss than a similar motor with a soft iron core.
83.
All losses in machines is given off as _______ .
84.
Starting resistors used with large motors drawing heavy currents are usually made in the form of ________ grids .
85.
Starting current is usually limited to about ________ of full load armature current.
This ensures that the motor can start under ________ and rapidly ________ to full load speed.
86.
If a starting resistor was connected in series with the shunt field, the motor would
________ be able to develop the correct ________ . Therefore, starting resistors are connected in ________ with the ________ .
87.
To measure the speed of a machine, you would use a ________ , and they can also be used to provide ________ as part of a ________ control system.
88.
Two types of ________ are ________ and variable-reluctance
89.
A ________ is used to convert electrical pulses into mechanical movements.
90.
The control system used to position rolls in a steel rolling mill is a ________ , and the type of motor used would be a ________ .
91.
Stepper motors are used in computer to ________ the read/write head in a computer disk drive.
92.
Reluctance in a magnetic circuit of constant length and cross sectional area is inversely proportional to __.
93.
The relationship between direction of induced emf, field polarity and the direction of motion is determined by _________________ rule.
94.
When a changing current in one coil is used to induce an emf in a separate coil, this is called _________________ induction.
95.
A multiplier is a resistor connected in moving coil meter. series
to extend the range of a
96.
The inductance of an air cored coil can be increased by inserting an
into the coil.

Electromagnetic Applications Miller College Missing Words
97. In a dc motor the generated emf (Eg)is ___________ than the terminal voltage (Vt)
98. The size of a rotating force on the armature conductor is determined by flux density, current and .
99.
A d.c machine that converts electrical energy to mechanical energy is a
100. Small poles located between the main field poles of a d.c machine are known as
.
101.
When measuring the resistance of the fields of a compound generator, the field with the lowest resistance is the field
102.
The current flowing in the interpole winding of a generator is equal to the current.
103.
The part of a d.c generator that converts a.c voltage to d.c voltage is called the.
__________
104.
In a d.c generator, the generated voltage (Eg) is terminal voltage (Vt).
105.
With Flemings left hand rule, the thumb represents the direction of
.
than the
106.
Maximum efficiency of a d.c. motor occurs when the constant losses
___________ the variable losses.
107.
The output power of a generator is equal to the input power ______________the losses.
108.
Iron losses occur mainly in the armature core and consist of loss and loss.
109.
A compound generator in which the series field mmf opposes the shunt field mmf is called ______________compounded.
110.
The field winding of a ___________ motor is connected in parallel with the armature.
111.
A shunt motor is best suited for __________________ speed drives.

Electromagnetic Applications Miller College Missing Words
112.
The type of D.C. motor used for traction purposes is generally
_________________ connected.
113.
Many anti shoplifting systems use ____________ devices to detect stolen goods
114.
A cross shown in a cross sectional view of a conductor shows current flowing
________ the conductor, whilst a dot shows current flowing ________of the conductor
115.
The polarity of an emf induced into a conductor depends on the ________ of the magnetic field and the ________ of the conductor.
116.
A magnetisation curve shows the relationship between ________ and ________ for magnetic materials
117.
If a material has a high ________ it is difficult to magnetise.
118.
For the diagram of figure 16 identify and label the following:
(a) ________________________
(b) ________________________
(c) ________________________
A
119.
Draw the Australian Standard symbols for the following, and give an example of an application for each one:
(a) an air cored inductor;
(b) an iron cored inductor;
(c) a fixed ferrite cored inductor;
(d) an adjustable ferrite cored inductor.********
C
B

Electromagnetic Applications Miller College Missing Words
1.
Residual magnetism
2.
decrease
3.
Decrease countertorque
4.
Cross magnetism demagnetism
5.
Magnetic neutral
6.
Increase incorrect
7.
Increase decrease
8.
Decrease armature reaction armature circuit
9.
Difference armature circuit
10.
Magnetisation curve
11.
yoke
12.
commutator, brushes
13.
Commutator ,ac
14.
Separately, self
15.
right
16.
right angle
17.
increase
18.
Flux density, length, velocity
19.
Deflecting, controlling, damping, moving
20.
Power, current, voltage

Electromagnetic Applications Miller College
21.
Iron, alternating
22.
Ω
/volt.
23.
Ammeter, loading
24.
hall, magnetic flux
25.
linked mutual inductance
26.
Transformers car igniton system
27.
data, voltage, mutual inductance
28.
Series, inductor
29.
Time constant, decrease, inductance, increase
30.
Relative motion conductor, magnetic flux
31.
Collapsing, induce voltage
32.
. flux inductance
33.
Direction motion, magnetice, inducted emf
34.
Silicon steel, hysteresis eddy current
35.
. Bifilar windings
36.
Increase, decrease, increase, increase
37.
Turns time *
38.
change
39.
Lenz’s law
40.
rate of change
41.
Induced, increase
42.
Decrease induced
Missing Words

Electromagnetic Applications Miller College
43.
Residual magnetism
44.
Series shunt compound
45.
Lower,demagnetising,armature reaction,voltage
46.
over,noload
47.
too low, residual flux
48.
Long shunt,series field,short shunt armature
49.
Cumulative series
50.
Strength,current,position,
51.
Force, radius
52.
increase, increase,decrease, decrease
53.
Opposes, back emf
54.
frame,commutator,brushes
55.
Back emf
56.
decrease , decrease , increase , increase
57.
armature flux
58.
series,shunt,compound
59.
decrease,decrease,increase,increase
60.
. Constant,variable
61.
High, low
62.
load, shunt field
63.
decrease,decrease,increase,increase *
64.
cranes,traction
Missing Words

Electromagnetic Applications Miller College
65.
constant,load,pressors,compressors
66.
Armature, field
67.
Armature,one
68.
machine tools
69.
series,shunt,compound
70.
Increase,increase,decrease
71.
Constant,constant
72.
torque,torque
73.
Decrease,increase,decrease
74.
armature,increase,two
75.
Less than,into,largere,out of
76.
Output,input,plus
77.
Windings,resistance,magnetic loss friction,windage
78.
Full,variable constant
79.
higher
80.
Maintence full
81.
Eddy current
82.
hysterisis
83.
heat .
84.
Cast iron
85.
150-200%,load,accelerate
86.
not,starting torque,series,armature
Missing Words

Electromagnetic Applications
87.
tach,feedback,speed
88.
Stepper,permanent
89.
Stepper motor
90.
Servo,servo motor
91.
position
92.
permeability
93.
flemings
94.
induction. mutual
95.
series
96.
Iron bar
97. less
98. length
99.
motor
100. interpoles
101.
series
102.
armature
103.
commutator
104.
greater
105.
motion
106.
equals
107.
minus
108.
Hysteresis eddy current
Miller College Missing Words

120.
121.
122.
Electromagnetic Applications Miller College
109.
differently
110.
shunt
111.
constant
112.
series
113.
Magnetostrictive
114.
In, out.
115.
Direction relative motion
116.
flux density magnetising force
117.
Reluctance
118.
Primary, secondary magnetic core
119.
The Australian Standard symbols for the following:
(a) an air cored inductor;
(b) an iron cored inductor;
(c) a fixed ferrite cored inductor;
(d) an adjustable ferrite cored inductor.
Missing Words

Electromagnetic Applications
123.
124.
Miller College Missing Words