ENGR205_HW7_DrAli

ENGR 205, Spring 2012 [Homework 7 (Chapter 10)]

Dr. Fahad Alajmi page 1

P10.1

For each circuit below, determine the real and reactive power.

*P10.2

For the circuit below, PT=1.9W and QT=900VAR. Determine P2 and Q2 .

20 30

50

9505



P10.3

For circuit shown in below, where IS=20<0O.

a) Compute PT and QT. b) Reduce the circuit to its simplest form.

*P10.4

A generator supplies power to an electrical heater, an inductive element, and a capacitor

as in the figure below.

a) Find P and Q for each load. b) Find the total active and reactive power supplied by the generator. c) Draw the power triangle for the combined loads and determine total apparent

power. d) Find the current supplied by the generator.

8

4

4 KWheater

20



P10.5

Find R and XL for the figure below.

*P10.6

For the figure below, XC =42.5Ω. Find R, P and Q .

*P10.7

Refer to the figure below, find P2 and Q3. Is the element in Load 3 inductive or capacitive?

15

600

400

1.5



P10.8

For the circuit below, w=10rad/s. Determine RT , R2 and XC and Leq .

P10.9

For figure 9, determine the total PT and QT.

*P10.10

For the circuit below, what is the source current.

3

750

800

2

60

220



*P10.11

For the figure below, Sgen=4835 VA. What is R.

P10.12

In the circuit shown below:

a) Calculate the load current IL and voltage VL. b) Calculate the average and reactive power delivered to the load. c) Calculate the average and the reactive power supplied by the source.

P10.13

The two loads in the circuit shown below, can be describe as follows: Load1 absorbs an average power of 8KW at a leading power factor of 0.8. Load2 absorbs 20KVA at a lagging power factor of 0.6.

5000

650

2



P10.14

For the circuit shown below,

a) Calculate the total average and reactive power delivering in the circuit. b) Calculate the average and the reactive powers associated with each source in the

circuit. c) Verify that the average power delivered equals the average power absorbed, and

that the magnetizing reactive power delivered equals the magnetizing reactive power absorbed.

P10.15

The load impedance in the circuit below absorbs 2500W and generates 5000 magnetizing vars. The sinusoidal voltage source develops 7500W.

a) Find the values of inductive line reactance that will satisfy these constrains. b) For each value of line reactance found in (a), show that the magnetizing vars

developed equals the magnetizing vars absorbed.

40



*P10.16

Three loads are connected in parallel across a 250V ( rms) line, as shown in figure18, Load1 absorbs 16kW and 18KVAR. Load 2 absorbs 10KVA at 0.6pf lead. Load 3 absorbs 8KW at unity power factor.

a) Find the impedance that is equivalent to the three parallel loads. b) Find the power factor of the equivalent load as seen from the lines input

terminals.

0.4 pf0.4 pf18

ENGR205_HW7_DrAli

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