A 480 V, 50 Hz, Y-connected six-pole synchronous generator has a
per-phase synchronous reactance of 1.0
Ω. Its full-load armature current is 60 A at 0.8 PF lagging. Its
friction and windage losses are 1.5 kW and
core losses are 1.0 kW at 60 Hz at full load. Assume that the
armature resistance (and, therefore, the I2R
losses) can be ignored. The field current has been adjusted such
that the no-load terminal voltage is 480 V.
a. What is the speed of rotation of this generator?
b. What is the terminal voltage of the generator if :
| i. ii. iii. |
it is loaded with the rated current at 0.8 PF lagging; it is loaded with the rated current at 1.0 PF; it is loaded with the rated current at 0.8 PF leading. |
c. What is the efficiency of this generator (ignoring the
unknown electrical losses) when it is operating
at the rated current and 0.8 PF lagging?
d. How much shaft torque must be applied by the prime mover at the
full load? how large is the induced
counter-torque?
e. What is the voltage regulation of this generator at
i. 0.8 PF lagging ii. at Unity PF iii. at 0.8 PF leading?
a. The figure below is a set of Synchronous Generator and
Synchronous Motor. The ratings of the
machines are as follows:
Synchronous Generator: . 3ph, 1.0 MVA, 2.3kV, 50Hz, 0.85 lagging
power factor, Xs =0.9 pu
Synchronous Motor: 3ph, 0.5 MVA, 2.3kV, 50Hz, 0.85 leading power
factor, Xs =0.8 pu
The generator is equipped with a voltage regulator which maintains
the terminal voltage at the rated value.
The motor delivers 500 hp and it field current is adjusted to make
it operate at unity power factor.
| i. ii. iii. |
Determine the synchronous reactance in ohms. Determine the excitation voltage of each machine. Draw the phasor diagrams |
a. The figure below is a set of Synchronous Generator and
Synchronous Motor. The ratings of the
machines are as follows:
Synchronous Generator: . 3ph, 1.0 MVA, 2.3kV, 50Hz, 0.85 lagging
power factor, Xs =0.9 pu
Synchronous Motor: 3ph, 0.5 MVA, 2.3kV, 50Hz, 0.85 leading power
factor, Xs =0.8 pu
The generator is equipped with a voltage regulator which maintains
the terminal voltage at the rated value.
The motor delivers 500 hp and it field current is adjusted to make
it operate at unity power factor.
The following test results are obtained for a 3ph, 25 kV, 750
MVA, 50 Hz, 3600rpm, star-connected
synchronous machines at rated speed.
| i. | Determine the unsaturated and saturated values of the
synchronous reactance in ohms and pu. If a short-circuit test is performed at constant field current 1500 A but at different speeds; 1000, 2000, 3000 and 3600 rpm. Determine the short-circuit current at these speeds above. Determine the field current if the synchronous machine delivers rated MVA to an infinite bus at 0.9 lagging power factor |
| ii. iii. |
If=1500A VLL(Open circuit)=25KV, IA(open circuit test)=10000A,VLL(air gap line)=30KV
g. Calculate the capacitance of a square parallel plate capacitor
having two
dielectrics εr1=2.5 and εr2=3.5 each comprising one half of the
area between
the plates. The area of a plate is 4.0 x 104 cm2 and the two plates
separated by
a distance of 20mm.
h. If a 24V volts electric potential is applied across the
terminals of this
capacitor described above, find the electric potential energy
stored in the
capacitor.
please answer these for me
In: Electrical Engineering
Classify the following descriptions as either Inferential statistics or descriptive statistics. Enter I if it is inferential statistics. Enter D if it is descriptive statistics.
The average age of the students enrolled in Statistics last semester was 29.7 years old.
There is a relationship between attending class and the grade you receive in the class.
Based on a random sample, it was concluded that the average cost of a hotel room in Chicago was greater than one in Atlanta.
A survey of 100 Statistics students found that the median score for test #1 was a 78.4%.
A study has concluded that the average credit card debt of college graduates had increased from the year 2009 to 2010.
The average Amazon.com rating of the book "The Complete Idiot's Guide to Statistics" by twenty-six reviews is 4.6 on a scale of 1 to 5.
In: Statistics and Probability
For this week's discussion, the focus will be on examining Porter's Five Forces as a tool for looking at the pressures on profits. Specifically, you will be looking at defining Porter's Five Forces and applying this tool to the market structures and pressures on profits of a chosen group of firms.
Instructions
In your discussion post, address the following:
In: Economics
In the case Las Vegas Sands v. Nehme, reported on page 380 of your textbook, the casino's "marker" was found by the court to be a negotiable instrument. The Venetian (a hotel owned by Las Vegas Sands LLC) was then allowed to sued Nehme for not paying a negotiable instrument. In a 500 word paper discuss the required elements for a negotiable instrument. Is it feasible that the casino marker contained all of these elements? Explain whether or not you think that gambling casinos should be able to advance credit to gamblers. From what you know about how alcohol affects a person's capacity to contract, is the fact that most gamblers are also consuming alcohol a factor in your decision? Do you think people would not gamble as much if casinos did not offer "markers?"
In: Economics
1. Juan Martinez was reviewing his recent bank credit card account statement when he found two charges involving a hotel room rental and a meal, purchased on the same day in a city than Juan knew he had not been to. Their charges totaled $229.99 out of Juan’s $529.99 balance for the month.
a. What payment should Juan make on the account?
b. How should he notify the credit card issuer about the unauthorized use?
c. Once the matter is resolved, what should Juan do to ensure
that his credit history is not negatively affected by this
error?
2. Explain the conditions that might make bankruptcy necessary. How might you use the services of a credit counselor?
In: Finance
What is the management fee (1) on a per available room basis and (2) as a percentage of total revenue for a 255-room hotel located in California that had an occupancy level of 62%, ADR of $84.53, a room revenue to total revenue % of 56.4%, and a gross operating profit % of 24.8%? The management fee agreement stipulated that the company would receive 3% of gross revenue, and 10% of gross operating profit.
1. lease use the information from Question 10 to calculate the Total mgmt fee.
Total mgmt fee (round to whole number) $ ___
2. Please use the information from Question 10 to calculate the Mgmt fee on PAR basis.
Mgmt fee on PAR basis (round to two decimal places) $ ___ PAR/yea
In: Finance
For this week's discussion, the focus will be on examining Porter's Five Forces as a tool for looking at the pressures on profits. Specifically, you will be looking at defining Porter's Five Forces and applying this tool to the market structures and pressures on profits of a chosen group of firms.
Instructions
In your discussion post, address the following:
In: Economics
A new study was done that included responses from 600 randomly sampled quests, of which 55% said they register using the hotel website. If the true proportion were 50% or less, what is the probability your sample data would produce a sample proportion of 55% or higher? Be sure to set up the two competing hypotheses and provide a statistical conclusion statement at a 2% level of significance for your results.
(Be sure to write out/ calculate how you find X, thank you) (Also, if you know how to find the type 1 error can you explain how you got it?)
2. Using Minitab, repeat the problem. Copy and paste it, please. (can't find it, This is really confusing!)
In: Statistics and Probability
Theresa Nunn is planning a 30-day vacation on Pulau Penang, Malaysia, one year from now. The present charge for a luxury suite plus meals in Malaysian ringgit (RM) is RM1,043/day. The Malaysian ringgit presently trades at RM3.1350/$. She determines that the dollar cost today for a 30-day stay would be $9,980.86. The hotel informs her that any increase in its room charges will be limited to any increase in the Malaysian cost of living. Malaysian inflation is expected to be 2.7191% annum, while U.S. inflation is expected to be 1.252%.
a. How many dollars might Theresa expect to need one year hence to pay for her 30-day vacation?
b. By what percent will the dollar cost have gone up? Why?
In: Finance
Theresa Nunn is planning a 30-day vacation on Pulau Penang, Malaysia, one year from now. The present charge for a luxury suite plus meals in Malaysian ringgit (RM) is RM1,043/day. The Malaysian ringgit presently trades at RM3.1350/$. She determines that the dollar cost today for a 30-day stay would be $9,980.86. The hotel informs her that any increase in its room charges will be limited to any increase in the Malaysian cost of living. Malaysian inflation is expected to be 2.7357% annum, while U.S. inflation is expected to be 1.22%.
a. How many dollars might Theresa expect to need one year hence to pay for her 30-day vacation?
b. By what percent will the dollar cost have gone up? Why?
In: Finance