Generals Flashcards
What is meant by the capacity rating of a lead-acid battery?
The number of hours a battery can supply a given current flow
What electrolyte is used in a lead-acid battery?
A mixture of sulfuric acid and water
Does the specific gravity of the electrolyte in a lead-acid battery increase or decrease as the battery becomes discharged?
Decreases
What is the specific gravity of a fully charged lead-acid battery?
Between 1.275 and 1.300
How many cells are there in a 24-volt lead-acid battery?
12
what is the range of temperatures of the electrolyte in a lead-acid battery that does not require a correction when measuring its specific gravity?
Between 70F and 90F
How do you treat a lead-acid battery compartment to protect it from corrosion?
Paint it with an asphaltic (tar-base) paint or with a polyurethane enamel
What is used to neutralize spilled electrolyte from a lead-acid battery?
A solution of bicarbonate of soda and water
How high should the electrolyte level be in a properly serviced lead-acid battery?
Only up to the level of the indicator in the cell
Why is the closed-circuit voltage of a lead-acid battery lower than its open-circuit voltage?
Voltage is dropped across the internal resistances of the battery
What gases are being released when a lead-acid battery is being charged?
Hydrogen and oxygen
What is the electrolyte used in a nickel-cadmium battery?
Potassium hydroxide and water
Why is the hydrometer not used to measure the state of charge of a nickel-cadmium battery?
The electrolyte of a nickel-cadmium battery does not enter into the chemical change when the battery is charged or discharged. Its specific gravity does not change appreciably.
Is the electrolyte level of a nickel-cadmium battery lowest when the battery is fully charged or discharged?
Fully discharged
What is the result of cell imbalance in a nickel-cadmium battery?
The low internal resistance allows current to flow between the unbalanced cells and generate heat
What is thermal runaway?
The large current flow allowed by the low internal resistance causes the cells to produce more heat than they can dissipate. The heat further lowers the internal resistance so more current can flow; this continues until the battery destroys itself
How may thermal runaway be prevented?
By carefully monitoring the temperature of the cells and controlling the charging current to prevent an excess of current flowing into the battery
How is it possible to know when a nickel-cadmium battery is fully charged?
Completely discharge the battery and give it a constant-current charge to 140% of its ampere-hour capacity
What is used to neutralized spilled electrolyte from a nickel-cadmium battery?
A solution of boric acid and water
What is the purpose of a sketch of a repair?
It shows a specific bit of information and includes the minimum amount of detail needed to manufacture the part
What is meant by minimum fuel as is used in the computation of aircraft weight and balance?
No more fuel than the quantity necessary for half an hour of operation at rated maximum continuous power. It is the maximum amount of fuel used in weight and balance computations when low fuel may adversely affect the most critical balance conditions.
What is meant by a proportion?
Two ratios equaled to each other
What is meant by a percentage?
A fraction having 100 as the denominator. EX 65% = 65/100