A 2-wire d.c. distributor, 500 m long is fed at one of its ends. The cross-sectional area of each conductor is 3·4 cm2 and the resistivity of copper is 1·7 μΩcm. The distributor supplies 200 A at a distance of 300m from the feeding point and 100 A at the terminus. Calculate the voltage at the feeding end if the voltage at the terminus is to be 230 V.

The diameter of an ACSR conductor is 1.1116 inches. The steel core has strands of diameters of 0.1291 inches each. If 54 Aluminum strands have the diameters of 0.1351 inches each, the number of Steel strands is: O A. 15 O B. None of choices are correct O C. 19 O D.7 O E. 27

Question 1 Select all that apply. Which of the following are considered to be "core losses"? 12R heating loss Flux lines that bulge out at core gaps Currents that circulate within the machine non-ferrous components Field Lines that circulate around conductors and coils Rapid Changes in Domain orientation

The diameter of an ACSR conductor is 1.162 inches. The steel core has 7 strands of diameter 0.1291 inches each. If Aluminum strands have the same diameter as that of a steel strand, the number of Aluminum strands is: O A. None of choices are correct O B. 36 O C. 74 O D. 54 O E. 45

A 2-wire d.c. ring distributor is 300 m long and is fed at 240 V at point A. At point B, 150 m from A, a load of 120 A is taken and at C, 100 m in the opposite direction, a load of80 A is taken. If the resistance per 100 m of single conductor is 0-03 Q, find :(i) current in each section of distributor(ii) voltage at points B and C * IA 150 m 120 A в A 240 V 100 m I - 120 IA - 200 80 A

H. W.: The cost of a 2-core feeder cable, including installation is (90 a + 20) per meter and the interest and depreciation charges are 10 per cent. The cable is 2 km in length and cost of energy is 4% per unit. The maximum current in the feeder is 250 A and the demand is such that the current copper loss is equivalent to what would be produced by the full flowing for 6 months. If the resistance of a conductor of 1 square cm and 1 km length is 0.173 Q, calculate the most economical cross-sectional area.

Question 1 A ferromagnetic core with a relative permeability of 1500 is shown in Figure 2. The dimensions are as shown in the diagram, and the depth of the core is 7 cm. The air gaps on the left and right sides of the core are 0.070 and 0.020 cm, respectively. Because of fringing effects, the effective area of the air gaps is 5 percent larger than their physical size. If there are 400 turns in the coil wrapped around the center leg of the core and if the current in the coil is 1.0 A, what is a) the flux in each of the left, center, and right legs of the core? b) the flux density in each air gap? 7 cm ст ст 30 cm 30 cm 7 cm 400 turns 0.05 cm 30 cm 0.07 cm 7 cm Core depth = 7 cm Figure 2

What is the ampacity of this conductor

69 Ambi a TN conductor is installed in a location where the ambient 4. The ampacity of 15 current-carrying 10 RHW aluminum conduc- tors in a raceway in an ambient temperature of 75°F is 1. on tactor for conductor ampacity in this location is (a) 12A (b) 15A (c) 22A (d) 30A 0.71 0.82 0.88 d0.96 5. An) ne ambient temperature is 71°C, the minimum insulation emperature rating that a conductor must have and still have THHN conductor is required for a 19.70A noncontin- uous load if the ambient temperature is 75°F and there are nine current-carrying conductors in the raceway in a dry location. the capacity to carry current is (a) 14 (b) 12 A) 60°C A 90°C 0 105°C (c) 10 (d) 8 120°C 6. 6.11 Ampacity Adjustment [310.15(B)(3)(a)] The ampacity for each of nine current-carrying 10 THW conduc- tors installed in a 20 in. long raceway is (a) 25A 1 The ampacity of six current-carrying 4/0 XHHW aluminum con- ductors installed in a ground floor slab (wet location) is (b) 30A (c) 35A (d) 40A a) 135A b)…

3. A two conductor main A B, 500 m in length is fed from both ends at 250 volts. Loads of 50 A, 60 A, 40 A and 30 A are tapped at distance of 100 m, 250 m, 350 m and 400 m from end A respectively. If the X- section of conductor be 1 cm and specific resistance of the material of the conductor is 1-7 u 2 cm, determine the minimum consumer voltage. 1245-07 V|