Often, we encounter delta-connected loads such as that illustrated in Figure P2.21, in three-phase power distribution systems (which are treated in Section 5.7). If we only have access to the three terminals, a method for determining the resistances is to repeatedly short two terminals together and measure the resistance between the shorted terminals and the third terminal. Then, the resistances can be calculated from the three measurements Suppose that the measurements are Ras=12 Ω , Rbs=20 Ω , and Rcs=15 Ω . c) Where Ras is the resistance between terminal a and the short between b and c , etc. Determine the values of Ra, Rb, and Rc. (Hint: You may find the equations easier to deal with if you work in terms of conductances rather than resistances Once the conductances are known, you can easily invert their values to find the resistances) Figure P2.21
Often, we encounter delta-connected loads such as that illustrated in Figure P2.21, in three-phase power distribution systems (which are treated in Section 5.7). If we only have access to the three terminals, a method for determining the resistances is to repeatedly short two terminals together and measure the resistance between the shorted terminals and the third terminal. Then, the resistances can be calculated from the three measurements Suppose that the measurements are Ras=12 Ω , Rbs=20 Ω , and Rcs=15 Ω . c) Where Ras is the resistance between terminal a and the short between b and c , etc. Determine the values of Ra, Rb, and Rc. (Hint: You may find the equations easier to deal with if you work in terms of conductances rather than resistances Once the conductances are known, you can easily invert their values to find the resistances) Figure P2.21
Solution Summary: The author calculates the value of resistance R_as and the short between the two.
Often, we encounter delta-connected loads such as that illustrated in Figure P2.21, in three-phase power distribution systems (which are treated in Section 5.7). If we only have access to the three terminals, a method for determining the resistances is to repeatedly short two terminals together and measure the resistance between the shorted terminals and the third terminal. Then, the resistances can be calculated from the three measurements Suppose that the measurements are Ras=12
Ω
, Rbs=20
Ω
, and Rcs=15
Ω
. c) Where Ras is the resistance between terminal a and the short between b and c, etc. Determine the values of Ra, Rb, and Rc. (Hint: You may find the equations easier to deal with if you work in terms of conductances rather than resistances Once the conductances are known, you can easily invert their values to find the resistances)
With no load attached, the voltage at the terminalsof a particular power supply is 50.8 V. When a 10-Wload is attached, the voltage drops to 49 V.a. Determine vS and RS for this nonideal source.b. What voltage would be measured at the terminalsin the presence of a 15- load resistor?c. How much current could be drawn from this powersupply under short-circuit conditions?
Please answer the following points in detail and rigorously. Instead ofresort to formulas, develop from basic principles (laws ofvoltages and currents, definition of electrical power, properties ofphasors, among others)
d) Show that the complex power consumed by two elements in parallel is the sum of the individual complex powers. After, repeat the procedure but for two elements in series.
e) What meaning would you give to the P consumed by an element? Which to Q?
f) Suppose you know P and Q for a two-terminal element. What is the power factor of this element? When would i be in early and when behind?
g) Suppose you know the equivalent resistance R and the reactance X equivalent of a two-terminal passive network. What is the factor power of red bliss? When would I be in advance and when in backwardness?
Derive the Norton equivalent network with respect to terminals PQ for the network shown in Figure below and hence determine the magnitude of the current flowing in a 2Ὡ resistor connected across PQ
Chapter 2 Solutions
Electrical Engineering: Principles & Applications Plus Mastering Engineering with Pearson eText -- Access Card Package (7th Edition)
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