作者: kira1121 (不顧一切) 看板: FCUProblems
標題: [考古] 電機機械(二)/張正泓/982期中考
時間: Mon Jun 28 16:27:57 2010

[開課學院]:    資電學院
[開課系所]:    電機系
[課程名稱]:    電機機械
[老師名稱]:    張正泓   老師
[開課學期]:    98-2
[類型]:        98-2期中考



[1]In the laboratory, an armature was designed to have two sets of commutators

 mounted at both ends.

(a)What is the purpose of this armature ?

(b)Sketch some diagrams to aid your answer.



[2]Explain the following terminologies in detail

(a)armature reaction

(b)imcomplete commutation

(c)cross magnetization

(d)leading pole tip



[3] A series dc motor has armature constant of 22 ,armature winding resistance

of 0.055 ohm , field winding resistance of 0.035 ohm , flux per pole of 0.028

weber . The source voltage is 220V anf the line current is 300A .The core loss

and friction loss are 1680W anf 1000W , respectively . Find the motor speed in

rpm for this motor.



[4] Find the efficiency on rated load for the motor in [3].




[5] A separately excited dc motor with armature supplied from a source of

variable potential difference ( 0 to 300V ) .The speed is to vary from 0 to

1800 rpm.If the field flux is maintained constant .Ignore all losses ,find the

rated armature current if the load torque is 22 kg.m.



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※ 編輯: kira1121        來自: 61.62.104.252        (07/13 12:12)