[開課學院]: 資電學院
[開課系所]: 電機系
[課程名稱]: 電機機械(一)
[老師名稱]: 張正泓 老師
[開課學期]: 98-1
[類型]: 98-1期中考
[1]In the laboratory,two sets of single-phase transformers ,one with air while
the other one none ,are under test.Sketch the related wiring diagrams and the
wave diagrams.Also analyze diagrams shown on the O.S.C.
[2]What are the oriented silicone steel sheets?
[3]What does stacking factor mean ? Describe briefly.
[4]A three-phase , 220 V , 60 Hz source supplies power to
(a)Load No.1:20 kW , power factor of 1.0 ;
(b)Load No.2:125 kVA , power factor of 0.6 (lagging)
(c)Load No.3:20 hp , power of 0.85 (lagging)
Calculate the power factor of this system .
[5]Sketch the complete current phasor diagram for the power system in [4] if
power factor is improved to 0.9. Using the diagram to calculate the line
current (polar form.)
[6]A 60-Hz voltage is of instantaneous value of
v(t)=12sin98.5t + 10sin188.5t + 258sin377t + 9sin 1885t volts .Calculate the
distortion factor(%) of this voltage.
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