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

Rotational Motion Linear Velocity.Angular Velocity Acceleration.Angular

Newton’s Law of Rotation (Fig1-2.) (force applied) (perpendicular distance) (J:moment of Inertia.)

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

Magnetic Flex Φ,B Magnetic Flex Φ Magnetic Flex Density B

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)

EX 1-2 given : B,N, R find: R, Ф, I

EX 1-3 given : N, I, R find: R, Ф

1.6 Induced Force on a wire Motor action I

1.7 Induced Voltage + _

1.8 the Linear DC Machine Fig1-19.

Starting the DC Machine

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

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

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.

DC Machine

DC Machinery Fundamentals

DC Gen

DC & AC Gen

DC Generator

The Induce Torque

Structure

Ex 8-1 Give: a. Switch closed Steady state:

b. Starting condition Noload steady-state condition

C. load torque is applied ; 1.Speed decrease:…………………. 2.Rotor current:…………… 3. 4.until:

Power supplied to the shaft: Power out of battery:

d. A Torque Is Applied in Direction of Motion, a. The rotor accelerates ; Speed increase

D b. c. d. (charge)

DC machine basics( 換相 ) South pole X Force North pole X X Angular velocity Zero Force X

換相 Commutation

Basic theory

8.2 Commutation (2P) 折疊 波繞

Lap-wound A lap winding is m-plax; Pitch: Current path: 折疊

Lap-Wound

折疊繞

均壓器

The Wave Winding Pitch: C is the number of coil on the rotor. Current path: Multiplex wave

蛙腿繞

8.4 Problems With Commutation Armature Reaction Neutral-plane shift a.Arcing and sparking b.Total average flux is decrease flux weakening. ( ) Voltage will be induced in the …. commutation segment.

電樞反應

換相極

補償繞組

Armature Reaction

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

Basic theory

Ex3.3

Ex3.4

Ex 3.4b

Ex3.4 c

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 )

效率 (gen)

效率 (motor)

Losses Generator Motor

Voltage Regulation