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1. The resistance 2000 ohm is relevant to the quantity of electricity in the discharge or not why?
& H C* w7 O# T2 @+ C5 T, R/ c电阻2000ohm大小 是否与放电量有关。为什么？
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' B0 D2 G% P! r' ^! |( E4 y& s2. We use the relay and push button switch to control the motor and to draw the self-holding (locking) relay circuit including the control and main circuit to avoid the unexpected start to cause the hazards when the supply is recovered.; n9 I n# n/ O) g: a( O
我们用继电器和按钮开关来控制马达. 画出自锁电路（包括控制电路和主回路）为了防止在电源恢复后突然起动引起伤害，。! U6 g, L: _$ o. x3 A( a
/ _! b# Y5 [! T- n$ g' H3. Please draw the voltage doubler circuit with diodes and capacitors.
, X' w9 }4 @1 y' O1 K2 k' F# ~- q画出两倍压整流电路。( G- \4 W' L4 @+ `' U2 h
' a# p. i# X; ^7 f& U. L: W4. Why will the capacitors in the auxiliary winding of motor usually be rated higher than the rated input voltage? 为什么电容起动马达副绕阻中的电容两端电压一般会大于额定输入电压？- E) A0 ]6 ?, w) `1 J4 v
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5.What is the definition of power factor (功率因数定义是什么)? What are the true power(有功功率定义是什么) and active power(无功功率定义是什么) and the apparent power(表观功率定义是什么)?
: W+ \" q" k" j) Z5 F6. A voltage transformer (VT) is like a voltage source. At what load is it most accurate when using the VT during the measurement? Why?
5 J4 Q+ C( V7 U+ i/ E电压变压器象一个电压源. 当用它来测量电压时, 在什么负载下精度比较精确? 为什么? |
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发表于 2009-4-15 12:50
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