Batteries

Which of the following statements is/are generally true regarding the charging of several aircraft batteries together? 1. Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method. 2. Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method. 3. Batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method.

A. 3 B 2 and 3 C. 1 and 2

The electrolyte of a nickel-cadmium battery is the lowest when the battery is

As a nickel-cadmium battery becomes discharged, some of the electrolyte is absorbed by the plates when the battery is fully discharged, its electrolyte level is the lowest.

Nickel-cadmium batteries which are stored for a long period of time will show a low liquid level because

If a nickel-cadmium battery is stored for a long period of time, some of the electrolyte in the cells will be absorbed into the plates, and the level will drop. The electrolyte level will rise when the battery is given a freshening charge before it is put into service.

When referring to an electrical circuit diagram, what point is considered to be at zero voltage?

If there is an open circuit in R(1), the base and the collector will have the same voltage. The base current will be maximum, and the light cannot be turned off.

The method used to rapidly charge a nickel-cadmium battery utilizes

Nickel-cadmium batteries can be rapidly charged by using a constant-potential charger (constant voltage and varying current). The charge is continued only until the current tapers off and stabilizes.

What is the purpose of the ground symbol used in electrical circuit diagrams?

The ground symbol used on electrical schematic diagrams indicates that there is a return path for the current between the source of electrical energy and the load.

What may result if water is added to a nickel-cadmium battery when it is not fully charged?

The level of the electrolyte in a nickel-cadmium cell changes as it is discharged and charged. The level is lowest when the cell is discharged and highest at the end of the charging cycle. If water is added to a cell when some of the electrolyte has been absorbed into the plates, the level will be too high when the cell is fully charged. Some of this excess liquid will spew out of the cell when it is near the end of its charge

How much power must a 24-volt generator furnish to a system which contains the following loads? UNIT RATING One motor (75 percent efficient) 1/5 hp Three position lights 20 watts each One heating element 5 amp One anticollision light 3 amp

The motor is 1/5 hp, therefore 746 watts (1hp) / 5 = 149 watts. This is the output of the engine. It takes more energy to produce 149 watts -- find this with the efficiency rating, 149/X = 75/100; X = 199. Therefore, the 1/5-horsepower motor that is 75 percent efficient requires 199 watts. The three position lights require a total of 60 watts. The heating element requires 120 watts. The anticollision light requires 72 watts. The total power the generator must produce is 451 watts.

The potential difference between two conductors which are insulated from each other is measured in??

The potential difference between two conductors is a measure of the electrical pressure difference between the conductors. Electrical pressure is measured in volts.

Which of these will cause the resistance of a conductor to decrease?

The resistance of a conductor varies directly as its length, inversely as its cross-sectional area, and directly with the resistivity of its material. Either decreasing the length or increasing the cross-sectional area of a conductor will cause its resistance to decrease.

What unit is used to express electrical power?

The watt is a measure of electrical power. The volt is a measure of electrical pressure.The ampere is a measure of electrical current flow.

What will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on?

When a voltmeter is connected across a closed switch in perfect condition or a good fuse, it will read zero voltage. A voltage drop of up to 0.2 volts is acceptable with maximum circuit current flow through the switch.

What determines the amount of current which will flow through a battery while it is being charged by a constant voltage source?

When a battery is charged by the constant-voltage method, a voltage somewhat higher than the open-circuit voltage of the battery is placed across the battery terminals. When the battery is in a low state of charge, its voltage is low and the constant-voltage charger will put a large amount of current into it. As the charge continues, the battery voltage rises and the current going into the battery decreases. When the battery is fully charged, only enough current flows into it to compensate for the power lost in its internal resistance.

The presence of any small amount of potassium carbonate deposits on the top of nickel-cadmium battery cells in service is an indication of

When a nickel-cadmium battery is fully charged, the battery becomes hot and the electrolyte bubbles. This causes some of the electrolyte to spew out of the top of the cell through the cell vent. When the water evaporates from the spewed-out electrolyte, it leaves a deposit of potassium carbonate, a white powder.

Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true? 1. When testing the specific gravity of the electrolyte of a lead-acid battery, the temperature Is unimportant 2. No correction is necessary when the electrolyte temperature is between 70°F and 90°F. 3. A correction of 0.4 should be subtracted from the specific gravity reading for each 10° above 80°F, and 0.4 should be added to the specific gravity reading for each 10° below 80°F.

When testing the specific gravity of the electrolyte of a lead-acid battery, the temperature must be taken into consideration. No correction is necessary when the electrolyte temperature is between 70°F and 90°F. A correction of 0.4 should be added to the specific gravity reading for each 10° above 80°F, and 0.4 should be subtracted from the specific gravity reading for each 10° below 80°F. THEREFORE THE ANSWER IS 2

The correct way to connect a test voltmeter in a circuit is

in parallel with an energized load; A voltmeter must always be connected in a circuit in parallel with the unit whose voltage is to be measured.