QUESTIONS AND ANSWERS
What is the most energy-efficient type of common power plant? Hint: It's also one of the
oldest.
ECE 3600 Exam 1 Fall 2013 - ANS Hydroelectric
Name 3 sources of electrical power for the grid which do not produce greenhouse gasses by
normal operation.
ECE 3600 Exam 1 Fall 2013 - ANS 3 of these: Hydroelectric, wind, solar (steam or solar-cells),
nuclear, geothermal
Decribe how a combined-cycle, natural gas, power plant works and achieves its high efficiency?
ECE 3600 Exam 1 Fall 2013 - ANS The "waste" heat of a gas turbine is then used to run a
steam cycle generator.
Express power lost using the following: (Pin) and (η)
ECE 3600 Exam 1 Fall 2013 - ANS P losses = P in - η.P in
a) Why do transformers have a maximum voltage rating?
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, b) That is, what bad thing are you trying to limit by limiting the voltage?
ECE 3600 Exam 1 Fall 2013 - ANS a) Core saturation
b) Insulation breakdown would happen at higher voltage
Why do transformers have a maximum current rating?
ECE 3600 Exam 1 Fall 2013 - ANS Winding resistance & I^2*R heating
When accounting for the non-ideal characteristics of a power transformer, which of the
following is the most important (least often neglected)?
1.magnetization reactance
2.core losses
3.winding losses
4.leakage reactance
ECE 3600 Exam 1 Fall 2013 - ANS leakage reactance
(Look at diagram on exam)
You have a 120/40-V, 480-VA transformer. Can you use this transformer to transform 120 V to
80 V? If yes, show the connections and compute the new VA rating.
ECE 3600 Exam 1 Fall 2013 - ANS 960 VA; look at picture to confirm answer
a) How many single-phase transformers are required to transform 3-phase power. Give the
minimum number
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