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Practice Questions with Distracter Explanations

Instructions:

The following questions are designed to give you the opportunity to practice for the EGSA Electrical Gener-
ator Service Technician Certification exam and to determine areas where you may need study and review.
Once you have taken the practice questions, you can check your answers using this document from the
EGSA. This document contains explanations for most of the correct and incorrect answers. Section Num-
bers along with the questions number are listed for each question. From there, you can locate the text to use
for reference on your specific area of need. (Reference back to category/task area of study guide.)

Section 1: Basic Electricity

S1-Q1.) A three phase electric generator has coils which are wound with how many degrees of
separation?

a.) 6 º
b.) *120 º
Correct - A circle is 360º. Therefore, 360 degrees/3 coils (one for each phase) must be
120º out of phase with each other.
c.) 60 º
This would be for 6 phase power which does not exist.
d.) 150 º

S1-Q2.) Wattage is the measure of

a.) *Power
Correct - Wattage is the amount of work done by the potential (voltage) times the flow
(current). This may be converted to horsepower as 746 watts = 1 horsepower
b.) Current
This is only one component of wattage.
c.) Potential
Another component of wattage, but not the complete answer.
d.) Inductance
Not related to wattage mathematically.

S1-Q3.) An AC sine wave has which of the following characteristics?

a.) Peak-to-Peak Amplitude
A sine-wave may be measured by its peak-to-peak or peak value. Peak value is just Peak-to-Peak/2.
b.) A Root Means Squared (RMS) value
RMS is the “usable” value and is what meters (such as DVM’s) measure. It is Peak
voltage/√(2). √(2) = 1.414.
c.) A corresponding current sine wave
It is alternating CURRENT. If there is a voltage and it is placed across a load, a current will
flow. This current will alternate above and below 0 amps just like the voltage alternates
above and below 0 volts. If the load is purely resistive, the sine-waves will be in phase. If
the load is purely capacitive, the voltage sine-wave will lead the current sine-wave by 90 . If
o
the load is purely inductive, the current will lead the voltage sine-wave by 90 o.
d.) *All of the above
Correct. All of the responses are true regarding AC sine-waves.

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