F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023F2 OIC ENG latest june 2023
2. The most efficient method of voltage reduction, from the
stand point of power loss, even when placed in series
with the load, is the use of a/an .
a. Capacitor
b. inductor
c. resistor
d. transistor
Ans. C
3. In the flow of cycle of single phase AC current past any
given point in a circuit, the maximum current peak occurs
.
a. Three times
b. One time
c. Four times
d. Two times
Ans. D
4. It is the number of degrees when the voltage and current
are out of phase so that the true power is equal to zero.
a. 45 degree
b. 90 degree
c. 120 degree
d. 180 degree
Ans. D
5. What methods are used to control the time that current is
limited before full currents are applied?
a. Push button switch starter
b. Full voltage reversing starter
c. Combination starter
d. Wye-delta starter
Ans. D
6. What will be the RPM of a single phase, two pole
alternator that generates at 60 Hz output?
a. 600
b. 720
c. 360
d. 900
,F2 OIC ENG latest june 2023
Ans. C
,F2 OIC ENG latest june 2023
7. A three phase alternator is operating at 450 volts, 250
amps at 0.6 power factor. If the power factor
increases to 0.8, the KW load will increase by .
a. 38.97 KW
b. 155.88 KW
c. 166.91 KW
d. 194.85 KW
Ans. A
P = P2 – P1
P = 155.7 KW – 116.775 KW
P = 38.925 KW
9. If two alternators are operating in parallel with a load
greater than either one is capable of carrying one of them
has to be cut out you should.
a. Increase the voltage of the machine that is to stay
on the line
b. Eliminate some branch circuit to reduce the load
c. Increase excitation
d. Speed up the machine that is to stay on the line
Ans. B
10. A three phase alternator is operating at 450 volts, 250
amps at 0.6 power factor. If the power factor
increases to 0.8, the KW load will increase by .
a. 155.88 KW
b. 194.85 KW
c. 166.91 KW
d. 38.97 KW
Ans. D
11. The temperatures in AC generator are indicated by:
a. Imbedded thermocouples
b. Pyrometer
c. Deep well thermometers
d. Standard thermometers
Ans. D
, F2 OIC ENG latest june 2023
12. Which of the following causes vibration of an alternator
operating in parallel and eventually trips out on the
reverse power relay?
a. The alternator was operating out of synchronism
b. Flash over the alternator's collector rings
c. Over speeding of the vibrating alternator
d. The dropping of load by that alternator
Ans. A
13. What will be the result if the AC generator operating in
parallel looses its excitation without tripping the circuit
breaker?
a. Cause a low voltage differential to develop
between the armature & the bus
b. Cause high currents to be induced in the field
windings
c. Not affect the faulty generator due to the
compensation of the other generators
d. Cause the slip rings to melt
Ans. B
14. An AC generator produces 60 Hz at 1800 RPM. If the
generator speed is increased to 1830 RPM, what will
happen to the cycle?
a. remain to 60 Hz`
b. increase to 63 Hz
c. decrease to 59 Hz
d. increase to 61Hz
Ans. B
15. If the excitation of one of two alternators operating in
parallel is increased, the .
a. power factor will change in the lagging direction
b. power factor will change in the leading direction
c. ampere load will be greatly decreased
d. kilowatt load will be greatly increased
Ans. A
16. Voltage induced in the windings of an AC generator
depends mainly on .
a. the strength of the magnetic field
b. the number of field poles energized
c. the speed of which the stator windings rotate
d. All of the options
Ans. A
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LAWEXEPRT. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $17.99. You're not tied to anything after your purchase.
