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70 Cards in this Set
- Front
- Back
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A battery consists of cells connected in________ |
Series |
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Primary amd secondary cells mean what? |
Primary is non rechargeable and secondary is rechargable |
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Adding to a batteries plate mass does what? Adding plate area does what? |
Mass-Increases ability to produce current over longer period of time. Area- higher current shorter time. |
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What are two basic factors affect the capacity of a cell? |
Area and mass of the electrode plates |
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What causes the difference between the open circuit terminal voltage of a cell and its terminal voltage under load? |
The volt drop due to internal resistance |
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Lelanche cell is an example of what type of battery? |
Primary cell |
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Lelanche cell is referred to as a dry cell why? |
The electrolyte is not a liquid but mixture of zinc chloride and ammonium chloride paste. |
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The basic materials used for the electrodes in a lelanche battery are? |
Carbon rod and zinc rod |
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Alkaline batteries have an electrolyte solution of what? |
Potassium hydroxide and water |
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3 types of lead acid battery? |
Flooded cell. Gelled electrolyte. Absorptive glass mat AGM cell. |
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What does flooded cell mean in terms of lead acid battery type? |
The electrolyte is liquid. |
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What is the electrolyte in a flooded lead acid battery? And specific gravity of what? |
Diluted solution of sulphuric acid and water. 1.275-1.3 |
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Fully charged lead acid battery will have an open circuit voltage of? |
2.1v per cell and a specific gravity of 1.25 and 1.28 |
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What specific gravity is it recommended to charge a lead acid battery? |
1.210 |
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To prevent permenant damage to the plates in a lead acid cell battery terminal voltage should not drop below? |
1.75v per cell |
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What does the cold do to a lead acid cell battery? |
Decreases efficiency |
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What is the exhaust from lead acid batteries? |
Hydrogen and oxygen |
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Lead acid batteries require lots of maintenance. T or F |
T because they need to be refilled regularly as they vent gas and they can leak highly corrosive fluids. |
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Why are gas mixtures not release from gelled electrolyte batteries ? |
Microporous plate allow for recombining of h2 and 02 |
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Gelled electrolyte battery can deliver higher currents. T or F |
T for the same size of battery |
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Gelled electrolyte batteries capacity varies with the rate of ______ |
Current discharge |
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As a seperator plate the AGM is of lower resistance than the plates of a gelled cell and experiences much lower internal volt drop this results in what? |
Higher terminal voltage and xan supply load for longer periods of time at high discharge rates.. |
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What are two types of valve regulated batteries? |
Gelled amd AGM |
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Ni cad battery is a? |
Secondary cell |
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The poitive plate pf ni cad battery is made of? And the negative? |
Nickel hydroxide positive and cadmium hydroxide. |
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Nicad batteries have a terminal voltage of? |
1.2v |
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Advantages of nicad batteries over lead acid are? |
Higher energy to weight ratio. Low internal resistance. Faster recharge rates. Long storage life. Better at lower temps. Longer life cycle. Capable of complete discharge recharge without damage. Lower maintenance for vented type as water does not need to be added. |
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A nickel metal hydride battery can store how many watt hrs per kilogram? |
100 watt hrs per 1 kg |
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Lead acid battery can store how many watt hrs per kg? |
25 watt hrs per kilogram |
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What is the positive temperature coefficient used for? |
Its a safety device that stops current flow keeping the battery from overheating in a lithium battery |
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What is the electrolyte in a lithium battery? |
An organic solvent called ether |
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What is the positive and negative electrode in a lithium cell? |
Lithium cobalt oxide for positive and carbon for negative. |
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Advantages of lithium batteries are? |
Lightweight. High energy density due to the highly reactive element. Hold their charge 5% per charge per month. No memory affect. They can go through hundreds of charge and discharge cycles. |
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Disadvantages of lithium batteries? |
Only last two to three years. Sensitive to high temperature. Complete discharge of the battery will destroy it. Monitored by onboard computer to manage it. Sometimes can burst into flames. Very expensive. |
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A lithium cell produces about________times the voltage of a alkaline battery cell. |
2 |
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Outer shell of lithium case is made of what? |
Metal |
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What is the seperator made from in lithium battery? |
Plastic |
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What can happen if a fully charged battery is connected in parallel with a dead one? |
One could explode |
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What can cause circulating current flow between two batteries that are connected in parallel? |
Caused by difference in terminal voltages between the battieries |
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Why is it not advisable to leave lead acid battery in a discharges condition for a long period? |
The sulphate on the plates crystalize and decrease efficiency |
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What is ampere hour rating? |
Is for a battery that gives an indication of total energy capacity. Current is multiplied by time. If a battery has a capacity of 48 AH at an 8 hr rate. It means the battery is capable of delivering 6 A continuously for 8 hrs and at the end of this time the terminal voltage will not have fallen below 91% of its rated voltage. |
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What are cranking amps? |
Are a ratimg that indicates the current that can be drawn from a fully charged battery for 30 seconds at a temp of 0C without cell voltage falling below 1.2V per cell. |
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What are cold cranking amps? |
Rating that indicates the current that can be drawn from a fully charged battery for 30 seconds at a temp of 0F without cell voltage falling below 1.2V oer cell |
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What is cold cranking performance rating? |
Abbreviated CCA is the amount of starting current....good for starters and motors |
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What is reserve capacity rating? |
Quoted in minutes. Is the amount of time a lead acid battery can maintain a current of 25 Amps at 25C before volts drop to 1.75 per cell. Example. A reserve capacity of 60 means the cell can deliver 25 amps for 60 minutes and durimg this time the cell voltage will not drop below 1.75 volts. |
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4 components of the magnetic circuit in a generator are? |
Field yoke. Pole cores. Armature core. Air gap. |
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3 components of electrical circuit are? |
Field coils. Armature windings. Brushes. |
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Flux density is? |
Concentration of lines of magnetic force around a magnet represented by greek letter beta |
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Describe permeability |
How easily a material can be magnetized (greek letter mu) materials that conduct magnetic flux easily. |
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Describe reluctance |
Resistance to conduct a magnetic field or path |
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Lines of force prefere the path of least______ |
Reluctance |
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Retentivity is? |
A materials ability to retain magnetic properties also called residual magnetism |
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Describe saturation |
Magnetic materials contain magnetic domains. When these domains become fully aligned amd can no longer retain any more magnetic ability it is considered saturated |
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Strength of the magnetic field produced depends on what factors? |
Amount of current. # of turns. Type of core that is in the magnetic circuit. |
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What is the purpose of the field coils on a generator? |
Increase flux density |
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List three factors that affect generator voltage |
Flux density. Length of conductor in field. Velocity. |
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Lenz law of induction states what? |
The induced EMF will cause a current to flow in such a direction that it opposes the change that produced it |
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Retentivity is what? |
Ability of a material to retain magnetism |
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Slip rings are used to form what? |
Sinusoidal waveform |
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Laminated cores reduce? |
Eddy currents |
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Commutator is also know as? |
Split rings |
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The positive half of a sinusoidal wave form is know as? |
Alternation |
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The amount of emf produced in a cell will depend solely on the? |
Type of electrolyte and plate material |
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Mutual induction is the process of inducing emf where? |
Into another coil |
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The alberta legislation that provides comprehensive detailed information for employers workers suppliers and gov agencies regarding workplace health and safety can be found in? |
OHS code |
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A bundle of conduit must be lifted the best method to use is the |
Double wrap basket hitch |
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Difference between ac and dc is always the... |
Commutators and slip rings |
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Term ampere hour rating is used to specify... |
Current which can be supplied for a given time |
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When determining the capacity of a battery for an emergency lighting system the minimum time to be used is ... |
.5 hrs |
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Symbol unit of measure for charge |
Coulombs |
