Electricity 6 Of 7 Flashcards
The battery is the most important power source in use because?
It’s energy is self-contained
The battery is used mostly wherever a ___________ Power source is required.
Portable
The battery is also used as a _________ source of voltage in a voltage standard.
Calibrated
What are the two classes of battery’s?
Primary and secondary.
The __________ battery converts chemical energy into electrical energy directly, using the chemical materials within the cell to start the action.
Primary
The _________ battery must first be charged before it can convert chemical energy into electrical energy.
Secondary
The secondary battery is frequently called?
A storage battery.
The ______ is the basic unit of the battery.
Cell
The ______ battery is used when limited current is required and the _________ battery is used when a heavy current is required.
Primary,
Secondary
The metals in a cell are called?
Electrodes
The amount of chemical activity that the electrolyte causes and the type of metal used for the electrodes will help determine the__________ and __________ output of the cell
Voltage and current
What is a disadvantage of the primary wet cell?
As the battery is used, the negative electrode disintegrates.
The basic primary wet cell is usually called the __________.
Voltaic cell
3, 1.5 volt batteries connected in series produces how much voltage?
4.5v
How many voltage ratings do batteries have?
Two.
A no-load rating, and
A normal load rating
What determines the useful life of a cell?
The amount of current flowing through a cell.
A cell’s ratings and life depend on its _____________.
Internal resistance.
Lead-acid batteries should never be overcharged because?
Overcharging causes explosive hydrogen and oxygen gases.
When an electric charging current is applied to a lead-acid battery, one electrode turns into _____ and the other turns into ___________.
Spongy lead
Lead peroxide
To reduce Sulfation, the lead-acid cell must be kept _________, and the electorate level must be kept at least 3/8 inch above the plates.
Charged.
The state of charge can be determined by measuring the specific gravity of the electrolyte with a __________.
Hydrometer.
The photoconductive cell is basically a variable resistive device that permits more current to flow in a circuit when it is struck by____________.
Light
A photovoltaic cell uses dissimilar __________ materials and a thermoelectric cell used dissimilar metals.
Semiconductors
A ________ generator uses heat and chemical activity to generate a charge.
Thermionic
A generator produces electricity by the ____________ of a group of conductors in a magnetic field.
Rotation
What are the two types of generators?
Ac, and
Dc generators
When excitation current is produced from the generators own output, the generator is a _____________ generator.
Self-excited.
Batteries are rated according to the amount of ________ they can supply in a given amount of time.
Current
A simple dc generator consist of 4 basic parts. What are they?
1) a magnetic field
2) a conductor, in the form of a loop
3) a commutator
4) and brushes
The magnetic field of a generator can be produced by what two things?
A magnet or electromagnet
Armature reaction and self-induction of the armature coils tend to shift the position of the _________.
Neutral plane
Interpoles are connected in ___________ with the armature winding to oppose the magnetic field of the armature winding.
Series
In many generators, the brushes are electrically connected to the brush holders by braided copper wires called ___________.
Pigtails
The simplest ac generator consists of?
A magnetic field and a single rotating loop.
In an ac generator, the ends of the loop are some way connected directly to__________ instead of a commutator like the dc generator.
The brushes
How many degrees apart are the voltages of a three phase generator?
120 degrees
The wye connection gives an increase in ____________ but not __________
Voltage
Current
The delta connection increases ________ but not _________.
Current
Voltage
Control bus batteries are used to supply electrical power to: A) operate oil circuit breakers B) emergency pumps C) emergency lighting systems D) all of the above
D
The dry cell battery is a?
Primary cell
What is the main difference between a primary and secondary battery?
A primary battery cannot be charged while a secondary battery can.
Polarization is due to the neutral gas bubbles that collect around the?
positive electrode
A battery being charged begins to gas freely. The current should be?
Decreased
The number of negative plates in a lead-acid cell is?
Always 1 more than the number of positive plates.
