tailieunhanh - Ebook Electric machinery fundamentals (5th edition): Part 2

(BQ) Part 2 book "Electric machinery fundamentals" has contents: DC machinery fundamentals, DC motors and generators, single phase and special purpose motors, the universal motor, other types of motors, introduction to DC motors, the equivalent circuit of a dc motor,. and other contents. | CHAPTER 7 \ I DC MACHINERY FUNDAMENTALS ( LEARNING OBJECTIVES Understand how vo ltage is induced in a ro tating loop. Understand how curved pole faces con tribute to a constant flux, and thus more constant output voltages. Understand and be able to use the equation fo r induced voltage and torque in a de machine. Understand comm utation. Understand problems with commu tation, including armature reaction and L ~~ effects. Understand the power fl ow diagram for de machines. DC machines are generators that convert mechanical energy to de electric energy and motors th at convert de electric energy to mechanical energy. Most de machines are li ke ac machines in that Lhey have ac voltages and currents within them- de machines have a de output only because a mechanism exists that converts the internal ac voltages to dc voltages at thei r terminals. Since tllis mechanism is cal led a commutator, de machinery is also known as commutating machinery. The fund amental princi ples involved in the operation of dc mac hines are very simple. Unfortunately, they are usually so mewhat obscured by the complicated construction of real macrunes. This chapter wi ll first explain the principles of dc machine operation by us ing simple examples and then co nsider so me of the complications that occur in real dc machines. A SIMPLE ROTATING LOOP BETWEEN CURVED POLE FACES The linear machin e studied in Section served as an introducti on to basic machine behavior. Its response to loading and to changing magnetic fields closely 404 I I, DC MACHINERY FUNDAMENTALS 405 resembles the behav ior of the real de generators and motors that we will study in Chapter 8. However, real generators and mo tors do not move in a straight linethey rotate. The next step toward understand ing real de machines is to study the simplest possible example of a rotating machine. The simplest possible rotating de machine is shown in Figure 7- 1. It consists of a single loop of wire rotating about a .

• Điện - Điện tử
• Electric machinery fundamentals
• Electric machinery
• DC machinery fundamentals
• DC motors and generators
• The universal motor
• The equivalent circuit
• Introduction to DC motors
• Machinery principles
• Imachinery principles
• AC machinery fundamentals
• Synchronous generators
• Induction motors
• Synchronous motors
• DC motors DC and generators
• Special purpose motors
• AC MACHINERY FUNDAMENTA
• ERRATA FOR ELECTRIC MACHINERY
• transformers
• power electronic
• machinery fundamentals
• synchronous generation
• synchronous motor
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