Course Outline
  1. Power Systems
    • Sources of Energy
    • Generation
    • Transmission
    • Distribution
  2. Transformer
    • Theory and operation
    • Equivalent Circuit
    • Voltage Regulation
    • Efficiency
    • Characteristics From Test Data
    • All Day Efficiency
    • Maximum Efficiency
  3. DC Machines
    • Motor
    • Generator
Energy Conversion
Take Home Final Exam Quiz No. 2

Copy, paste and print the problems. Deadline of submission will be on Monday May 16, 2005 3:00PM. Late submission will not be accepted. Please take note of this... Good luck...

1. A long-shunt compound generator delivers a load current of 50A, at 25 kW and has an armature, series field adn shunt field resistances of 0.05 Ohm, 0.03 Ohm and 250 Ohms respectively. Calculate:
(a) the armature current
(b) the generated votage
(c) the power of the generator
(d) the efficiency of the generator

2. An 8-pole dc-shunt machine with 778 duplex-lap connected armature conductors and running at 500 rpm, supplies a load of 12.5 Ohm resitance at a terminal voltage of 250 V. The armature resistance is 0.24 Ohm and the filed resistance is 250 Ohms. Find the armature current, the induced emf and the flux per pole. Determine also the power across the generator and the efficiency of the machine.

3. A 4-pole dc machine with simplex lap connected armature, having field and armature resistances of 50 Ohms and 0.1 Ohm respectively supplies sixty, 100 V 40 W lamps. Calculate the total armature current, the generated emf and the input power. Calculate also the efficiency of the machine.

=============================

1. A 12kVA, 2,600/260V 50 Hz, transformer has a core loss of 85W and a copper loss of 170W. What is the maximum efficiency at 0.92 p.f.?

2. A 25 kVA 60Hz transformer has the following loadings with copper loss of 572W.

  1. Full Load 0.9 p.f. 9 hrs.
  2. 18kVA 0.82 p.f. 7 hrs.
  3. 12 kVA 0.707 p.f. 6 hrs.
  4. No Load

Calculate the total copper loss.

3. A 400 kVA 11,000/110V 50 Hz transformer has copper loss of 712W and a core loss of 518 W. What is the kVA rating of the transformer at maximum efficiency condition?

4. A 110 kVA distribution transformer has a maximum efficiency at 97.25% at 80% full load at 0.91 p.f. Determine the copper loss at full load condition.

5. A 320 kVA transformer has an ADE of 97.44% at the following loadings:

  1. 320 Kva 0.887 p.f. 8 hrs.
  2. 85% load 0.91 p.f. 7 hrs.
  3. 160 kVA 0.8 p.f. 3 hrs.
  4. No Load

Calculate the copper loss at full load if the magnetic core is 1121. 37W.

6. A 1000 kVA 66,000/6,600 Hz transformer has a maximum efficiency of 96.33% at 92% of full load at 0.87 p.f. and has the following measurements on its charateristics from test data:
SCT
V=3,490V
W=17,860W

NLT
V=6,600 V
Calculate the efficiency of the transformer at 0.8 full load 0.707 p.f.

7. A 120 kVA distribution transformer has a maximum efficiency of 98.30% at 0.83 full load and 0.83 p.f. Calculate its copper loss for the following loadings:

  1. 100 kVA 0.866 p.f. 8 hrs.
  2. 64 kVA 0.8 p.f. 6 hrs.
  3. 60% load 0.9 p.f. 5 hrs.
  4. half-load 0.707 p.f. 3 hrs.
  5. no load 2 hrs.

            Submit a report on the different sources of energy. Give a brief description of energy conversion and examples for such source. Your report must contain the following:
  1. title page
  2. table of contents
  3. report
  4. references
Deadline of submission will be on Friday June 21, 2002. Late submission will not be accepted.

Submit a report on the Different Types of DC machines. Include the equivalent circuit and a brief description of the machine. Deadline of submission will be on September 6, 2002.

HOME

Hosted by www.Geocities.ws

1