Electrical Engineering: Principles & Applications 6th. Edition by Allan R. Hambley | 9780133116649 | 0133116646

Basic Electrical

Electrical Engineering: Principles & Applications

19 SOLVED PROBLEMS

157 SOLVED PROBLEMS

Question: 15.5

A Magnetic Circuit with an Air Gap Consider the magnetic core with an air gap as shown in Figure 15.12(a). The core material has a relative permeability of 6000 and a rectangular cross section 2 cm by 3 cm. The coil has 500 turns. Determine the current required to establish a flux density of Bgap ...

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As shown in Figure 15.12(b), this magnetic circuit...

Question: 15.7

Calculation of Inductance Determine the inductance of the 500-turn coil shown in Figure 15.12 and analyzed in Example 15.5. ...

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In Example 15.5, we found that the reluctance of t...

Question: 11.2

Calculating Performance of Cascaded Amplifiers Consider the cascade connection of the two amplifiers shown in Figure 11.6. Find the current gain, voltage gain, and power gain of each stage and for the overall cascade connection. ...

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Considering loading by the input resistance of the...

Question: 10.7

Analysis Using a Piecewise-Linear Model Use the circuit models found in Example 10.6 to solve for the current in the circuit of Figure 10.20(a). ...

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Since the 3-V source has a polarity that results i...

Question: 10.5

Analysis by Assumed Diode States Use the ideal-diode model to analyze the circuit shown in Figure 10.16(a). Start by assuming that D1 is off and D2 is on. ...

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With D1 off and D2 on, the equivalent circuit is s...

Question: 7.4

Adding Binary Numbers Add the binary numbers 1000.111 and 1100.011. ...

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See Figure 7.7.

Question: 13.5

Analysis of the Fixed Base Bias Circuit Repeat Example 13.4 with β = 300. ...

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First, we assume operation in the active region. T...

Question: 13.4

Analysis of the Fixed Base Bias Circuit The dc bias circuit shown in Figure 13.18(a) has RB = 200 kΩ, RC = 1 kΩ, and VCC = 15 V. The transistor has β = 100. Solve for IC and VCE. ...

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We will eventually see that the transistor is in t...

Question: 2.1

Find a single equivalent resistance for the network shown in Figure 2.3(a). ...

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First,we look for a combination of resistances tha...

Question: 5.12

Analysis of a Wye–Wye System A balanced positive-sequence wye-connected 60-Hz three-phase source has line-to-neutral voltages of VY = 1000 V. This source is connected to a balanced wye-connected load. Each phase of the load consists of a 0.1-H inductance in series with a 50-Ω resistance. Find the ...

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Solution First, by computing the complex impedance...

Question: A.2

Polar-to-Rectangular Conversion Convert Z3 = 5 ∠30◦ to rectangular form. ...

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Using Equations A.3 and A.4, we have

x = |Z...

Question: A.3

Rectangular-to-Polar Conversion Convert Z5 = 10 + j5 and Z6 = −10 + j5 to polar form. ...

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The complex numbers are illustrated in Figure A.4....

Question: A.4

Exponential Form of a Complex Number Express the complex number Z = 10 ∠60◦ in exponential and rectangular forms. Sketch the number in the complex plane. ...

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Conversion from polar to exponential forms is base...

Question: A.5

Complex Arithmetic in Polar Form Given Z1 = 10 ∠60◦ and Z2 = 5 ∠45◦ , find Z1Z2, Z1/Z2, and Z1 + Z2 in polar form. ...

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For the product, we have

Z_1 × Z_2 = 10 ∠60...

Question: A.1

Complex Arithmetic in Rectangular Form Given that Z1 = 5 + j5 and Z2 = 3 − j4, reduce Z1 + Z2, Z1 − Z2, Z1Z2, and Z1/Z2 to rectangular form. ...

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For the sum, we have

Z_1 + Z_2 = (5 + j5) +...

Question: 17.5

Power-Factor Control A 480-V-rms 200-hp 60-Hz eight-pole delta-connected synchronous motor operates with a developed power (including losses) of 200 hp and a power factor of 85 percent lagging. The synchronous reactance is Xs = 1.4 Ω. The field current is If = 10 A. What must the new field current ...

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First,we determine the initial value of

E_r...

Question: 17.4

Synchronous-Motor Performance A 480-V-rms 200-hp 60-Hz eight-pole delta-connected synchronous motor operates with a developed power (including losses) of 50 hp and a power factor of 90 percent leading. The synchronous reactance is Xs = 1.4 Ω. a. Find the speed and developed torque. b. Determine the ...

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a. The speed of the machine is given by Equation 1...

Question: 17.3

Induction-Motor Performance A 220-V-rms 60-Hz three-phase wye-connected induction motor draws 31.87 A at a power factor of 75 percent lagging. For all three phases, the total stator copper losses are 400 W, and the total rotor copper losses are 150 W. The rotational losses are 500 W. Find the power ...

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The phase voltage is

V_s = V_{line}/ \sqrt{...

Question: 17.2

Starting Current and Torque Calculate the starting line current and torque for the motor of Example 17.1. ...

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For starting from a standstill, we have s = 1. The...

Question: 17.1

Induction-Motor Performance A certain 30-hp four-pole 440-V-rms 60-Hz three-phase delta-connected induction motor has Rs = 1.2 Ω R′r = 0.6 Ω Xs = 2.0 Ω X′r = 0.8 Ω Xm = 50 Ω Under load,the machine operates at 1746 rpm and has rotational losses of 900W. Find the power factor, the line current, the ...

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From Table 17.1, we find that synchronous speed fo...