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DC Machine 1. 直流發電機原理 磁場 法拉第定理與感應電壓 2. 交直流發電機與結構 3. 反電動式的電壓 4. 繞組方式 5. 電樞反應與解決方法 6. 電壓調整率
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Rotational Motion Linear Velocity.Angular Velocity Acceleration.Angular
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Newton’s Law of Rotation (Fig1-2.) (force applied) (perpendicular distance) (J:moment of Inertia.)
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Magnetic Field Ampere’s Law I Magnetic Field Intensity H 安培定律是說明電流產生磁場的基本定律。 磁場
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Magnetic Flex Φ,B Magnetic Flex Φ Magnetic Flex Density B
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Flux in the core Ф 電動勢 (v) 磁動勢的極性 (a) 簡單的電路; (b) 類比於變壓器鐵心之磁路。 磁動勢 (mmf)
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EX 1-2 given : B,N, R find: R, Ф, I
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EX 1-3 given : N, I, R find: R, Ф
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1.6 Induced Force on a wire Motor action I
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1.7 Induced Voltage + _
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1.8 the Linear DC Machine Fig1-19.
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Starting the DC Machine
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Linear DC Machine Behaves: 1.At Start: 2.Force: 3.Accelerate: 4.Reduce I : 5.Decrease F: 6.At F=0; 7.Move at a constant speed
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Linear DC Machine as a Motor: is applied to the bar: 1.Bar begins to slow down, 2.Induced voltage drops 3.Decrease current: 4.Increase 5.Until; Fig1-23
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Linear DC Machine as a Generator 1.Applied force (right), 2.Increase Velocity v 3.Induced Voltage 4.With, (Battery is charging) 5.Current 6.Induced force 7. 8.
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http://www.mpoweruk.com/machines.htm
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DC Machine
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DC Machinery Fundamentals
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DC Gen
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DC & AC Gen
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DC Generator
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The Induce Torque
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Structure
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Ex 8-1 Give: a. Switch closed Steady state:
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b. Starting condition Noload steady-state condition
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C. load torque is applied ; 1.Speed decrease:…………………. 2.Rotor current:…………… 3. 4.until:
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Power supplied to the shaft: Power out of battery:
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d. A Torque Is Applied in Direction of Motion, a. The rotor accelerates ; Speed increase
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D b. c. d. (charge)
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DC machine basics( 換相 ) South pole X Force North pole X X Angular velocity Zero Force X
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換相 Commutation
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Basic theory
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8.2 Commutation (2P) 折疊 波繞
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Lap-wound A lap winding is m-plax; Pitch: Current path: 折疊
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Lap-Wound
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折疊繞
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均壓器
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The Wave Winding Pitch: C is the number of coil on the rotor. Current path: Multiplex wave
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蛙腿繞
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8.4 Problems With Commutation Armature Reaction Neutral-plane shift a.Arcing and sparking b.Total average flux is decrease flux weakening. (8-24 8-25) Voltage will be induced in the …. commutation segment.
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電樞反應
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換相極
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補償繞組
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Armature Reaction
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Solutions to the Problems With Commutation Three approaches have been developed to correct the problems of armature reaction and voltage. 1.Brush shift(depend on load; G; M ) 2.Commutating poles or interpoles 3.Compensating winding
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Basic theory
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Ex3.3
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Ex3.4
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Ex 3.4b
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Ex3.4 c
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效率 與 損失 1. Copper Losses: 2. Core losses a. hysteresis loss b. eddy current loss 3.Mechanical Losses 4.Stray Losses (Miscellaneous Losses )
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效率 (gen)
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效率 (motor)
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Losses Generator Motor
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Voltage Regulation
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