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S4-Q92.) On electronically controlled diesel engines, electrical alarm and shutdown are processed
through the ECU to automatically alarm and/or shutdown the engine when needed?

a.) *True
Correct. The ECU and engine management soft ware are logical devices in use of alarm and/or
shutdown devices. They can be programmed to many variables including timing and air/fuel
ratio factors.
b.) False
Incorrect.

S4-Q93.) Battery chargers perform what function?

a.) Provide ignition voltage
Battery chargers are not part of the ignition system.
b.) *Rectify AC into DC and maintain proper DC voltage level
Correct. A battery charger may be a ½ wave, full wave, or bridge type rectifier. Since its output
is absorbed by a battery, noisy output is not an issue. The battery only requires that a proper
level of DC be maintained.
c.) Increase starting capacity
This would be known as a booster with ample capacity to provide several hundred amps of DC power
for short periods. While a booster may also be used as a battery charger, a battery charger does not
have the capacity to boost.
d.) Provides the field for the generator
This is not the normal method of providing a field. While separately excited generators have an
alternate source for the field, it is not a battery charger.

S4-Q94.) A hydrometer is used for what purpose?

a.) Checking the coolant level in the radiator
While specific gravity determines the coolant to water ratio, a hydrometer is not used to check level.
b.) *Measuring the specific gravity of the battery acid
Correct. Battery acid changes specific gravity during a chemical reaction. Since the charge/
discharge is a chemical reaction between the lead and the acid, the specific gravity will change
The hydrometer is used to determine how strong the acid is.
c.) Measuring for condensation inside the generator
Hopefully there is no condensation inside the generator. However, if it were it would be water and
water always has the same specific gravity and would not require a hydrometer. Hydrometers
measure specific gravity.
d.) Determining if there is water in the fuel
Hydrometers measure specific gravity. Water always has the same specific gravity and would not
require a hydrometer.

S4-Q95.) Baking soda serves what purpose in power generation?

a.) It is used as a desiccant to absorb moisture inside the generator
Baking soda is not a desiccant.
b.) It is used to remove the foul ozone odor left from the corona effect
Baking soda cannot remove ozone odor.
c.) *It is used to neutralize a battery acid spill
Correct. Baking soda is an effective neutralizer of battery acid. A baking soda/water paste can
also help to remove corrosion from battery terminals.
d.) None
See answer c.

EGSA Apprentice Certification Program Study Guide - Page 82