Electrical Engineering: Principles and Applications 5th. Edition by Allan R. Hambley | 9780132130066 | 0132130068 | Holooly

Basic Electrical

Electrical Engineering: Principles and Applications

164 SOLVED PROBLEMS

Question: 13.3

Determining the Operating Region of a BJT A given npn transistor has β = 100. Determine the region of operation if a. IB = 50 μA and IC = 3mA; b. IB = 50 μA and VCE = 5V; c. VBE = -2 V and VCE = -1V. ...

Verified Answer:

a. Since IB and IC are positive, the transistor is...

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. ...

Verified Answer:

For the product, we have

Z_1\times Z_2=10\...

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. ...

Verified Answer:

Conversion from polar to exponential forms is base...

Question: A.3

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

Verified Answer:

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

Question: A.2

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

Verified Answer:

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

x=\le...

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. ...

Verified Answer:

For the sum, we have

Z_1+Z_2=(5+j5)+(3-j4)...

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 ...

Verified Answer:

First, we determine the initial value of Er . Beca...

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 ...

Verified Answer:

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 ...

Verified Answer:

The phase voltage is

V_s=V_{\mathrm{line}}...

Question: 17.2

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

Verified Answer:

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

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