Electricity I Final
frog leg
Armatures are wound to provide high voltage, high current, or some specific combo of voltage and current. Which type of winding provides moderate voltage and moderate current?
compound
A generator containing both series and shunt field is called a _____ generator.
electromotive
A list of metals showing their willingness to accept electrons is called the ______ series of metals.
26,244
A wire that has a diameter of 162 mils has an area of _____ circular mils.
6V
Squarewave voltage varies between 0 and 12V. The positive pulses are 50 microseconds wide and a 50 microsecond gap between them. What is the avg DC?
True
T/F - A piece of wire that is one mil in diameter and one foot long is one mil-foot.
False
T/F - All insulations perform equally well in dry, damp, and wet locations.
True
T/F - CEMF and back-EMF are names for the voltage induced into the armature of a DC motor.
True
T/F - Most of the electric power in the world is produced by alternators.
brushes
The _____ ride against the commutator segments and are used to connect the armature to the external circuit of the DC machine.
surrounding air
The ambient air temperature considered in relation to a conductor ampacity is the temperature of the _____.
cell
The amount of voltage produced by an individual _______ is determined by the materials from which it is made.
86°F
The ampacities listed in Table 310.15 (B) are based on an ambient temperature of _______.
differential
The compound motor connection that should generally be avoided is the
Direct
The d'Arsonval meter movement is operated by applying _________ current to the coil.
Max. Operating Temperature
The insulation used on conductors cannot operate in all possible temps. the highest allowable temp is called the ____________.
Resistance
The longer the conductor, the more _____ it will have.
High power circuits
The low impedance voltage tester is most suitable for use in ___.
brushless DC
The motor that does not contain a wound armature, commutator, or brushes is the _______ motor.
resistance
The no-load voltage of a cell is greater than the normal load voltage because of the internal _____ of the cell.
field strength
The output voltage of a generator is usually controlled by the amount of ____.
heat/temp
Thermocouples produce voltage because of the action of 2 dissimilar metals. The voltage produced depends on the type of metals used and the _________ difference between the junction and the open ends.
Insulation
What is the nonconductive covering around a wire?
Galvanometer
What meter features a wire coil suspended between permanent magnet poles and operates on very tiny amounts of current?
Voltmeter
What meter is designed to be connected directly across the power source?
Oscilliscope
What meter measures an amount of voltage during a period of time and produces a 2-D image?
Wattmeter
What meter measures true power in a circuit?
Ohmmeter
What meter must NEVER be connected to a circuit when the circuit power is turned on?
pole pieces
What provides the magnetic field necessary for the operation of a DC machine?
secondary
What type of cell can be recharged?
primary
What type of cell cannot be recharged?
shunt field
When a compound motor is connected differential compound, the ______ determines the direction of rotation of the motor at no load or light load.
parallel
When a conductor is very large, it may become necessary to connect them in _______.
loading
When the connection of a meter to the circuit changes the entire circuit operation, this is known as the ___ effect.
3V
25 microseconds wide and 75 microsecond gap. What is the avg DC?
9V
75 microseconds wide and 25 microsecond gap. What is the avg DC?
cumulative compounding
A compound generator has both series and shunt field windings. When those windings are connected so they aid each other in the production of magnetism, that connection is called _______.
Shunt
A low resistance device used to conduct most circuit current away from the meter movement is an ammeter _____.
Analog Meter
A test meter that uses a scale and pointer to indicate values is an ____.
acid
A voltaic cell is constructed of two unlike metals and an _________, alkaline, or salt solution.
high
A voltmeter has very ____ resistance connected in series with the meter movement.
multi-range
A(n) _____ ammeter operates on more than one range by connecting the meter movement to different shunts.
series
An ammeter is connected in ____ with the load to permit the load to limit current flow.
wave-wound
Armatures are wound to provide high voltage, high current, or some specific combo of voltage and current. Which type of winding provides high voltage and low current?
lap
Armatures are wound to provide high voltage, high current, or some specific combo of voltage and current. Which type of winding provides low voltage and high current?
3
If there are more than ____ conductors in a raceway, the ampacity of the conductors must be derated.
Voltaic Pile
In 1800, Alessandro Volta was experimenting with producing electricity. He called his battery _____.
armature; shunt field
In a compound DC motor control circuit, the field loss relay will disconnect the _______ if power is lost to the ______.
20°C
In the American Engineers Handbook, the standard temp of material resistance is _____.
ampacities
In the National Electrical Code, the current carrying abilities of conductors are called the ____.
positive
Materials that increase their resistance with an increase in temp have a ______ coefficient of temp.
multi-range
Most voltmeters are _____ voltmeters, meaning they are designed to use one meter movement to measure several ranges.
2,000
NiCad cells can be charged and discharged about _____ times.
higher
Permanent magnet motors have _______ efficiency than conventional field-wound motors.
pressure
Piezoelectricity refers to electricity produced by some materials when they are subjected to _____.
few/large
Series field windings are connected in series with the armature. They are wound with _____ turns of fairly _______ wire.
battery
Several cells connected together that produce voltage are called a ______.
many/small
Shunt field windings are connected in parallel with the armature. They are wound with ______ of fairly _____ wire.
parallel
Shunt generators contain only a shunt field winding connected in ______ with the armature.
servomotors
Small permanent magnet motors that have lightweight rotors are often used as ________.
semi-conductor
Solar cells are constructed from a combination of P- and N-type _________ materials.
shunt
The DC motor, known as a "constant speed motor" is the _____ motor.
zinc-carbon
The LaClanche cell is also known as a ____ cell.
310
The National Electrical Code ____ contains tables dealing with conductors for general wiring.
printed circuit
The ServoDisc motor is often called a ________ motor.
current
The amount of energy a cell can deliver is called its ______ capacity?
compounding
The relationship of the strengths of the 2 fields in a generator determines the amount of ______.
Ayrton shunt
The resistor are connected in parallel with the meter on some ranges and in series for other ranges when a _____ is used.
armature
The rotating part of a generator is called the _____.
series
The series generator has only a series field, which is connected in ______ with the armature.
clamp-on
The series ohmmeter is used to measure _____ values of resistance
ServoDisc
The servomotor featuring a fiberglass and copper rotor is the _________ motor.
pulse width
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 _________.
armature resistance
The speed regulation of a DC motor is proportional to the _______.
diameter (squared)
The unit circular mil is equal to the
battery
The word ______ is often used in reference to a single cell.
correct for temperature and derate
There are 6 current carrying conductors in a raceway that is to be installed in an area with an ambient temperature of 90°F. It is necessary to ____.
3
To perform a load test on a lead-acid battery, the amount of the test current should be ____ times the ampere-hour capacity.
megger
To test wire insulation, a special type of ohmmeter called a ______ is used.
generator
What is a device that converts mechanical energy into DC electrical energy?
resistance
What is measured by the Wheatstone bridge?
d'Arsonval
What is one of the most common analog meter movements?
commutator
What is the component of a DC generator that converts the armature AC into DC?
8
What is the maximum current (amperes) that should be applied when charging an 80-ampere hour battery?
specific gravity
What is the measure of the amount of acid contained in water?
shunt
When the field winding in of a DC motor is connected in parallel with the armature, the motor is called a _______ motor.
series & shunt
A compound motor has _____ field windings.
Differential compounding
A compound generator has both series and shunt field windings. When those windings are connected so they oppose each other in the production of magnetism, that connection is called _______.
motor
A device that converts electrical energy into mechanical energy is a _______.
Hydrometer
A device used for measuring the specific gravity of a cell is called a _________.
Series Field Shunt Rheostat
In a generator, the ________ permits part of the current that normally flows through the series field to flow through the resistor.
False
T/F - A series motor may be operated with no load connected.
One to red and one to blue
There are two conductors, a red and a blue, installed in metallic conduit. You are using a megger to test for grounds. How should the 2 leads of the megger be connected?
One to red and one to blue
There are two conductors, a red and a blue, installed in metallic conduit. You are using a megger to test for shorts. How should the 2 leads of the megger be connected?
7.2
What is the terminal voltage of a nicad battery containing 6 cells?
