当步进电动机不改变通电状态,转子不动时,在轴上加一负载转矩,定子与转子有一个角位移,称为()。
A.步距角
B.调整角
C.相位角
D.失调角
A.步距角
B.调整角
C.相位角
D.失调角
当中央银行不改变货币政策时,政府希望不改变产出水平,又能降低通货膨胀2%时的最佳财政政策是什么?损失函数的值是什么? c.如果中央银行愿意合作,最佳政策组合是什么?损失函数的值多大? In some countries,the central bank is independent from the government.Consider a situationin which the government wants to reduce inflation without changing output,but the central bank would not change monetary policy. a.Can the government achieve its objectives by using only fiscal policy?Why? b.Assume that the effect of instruments on targets in this economy are represented by the following model(in deviations from the baseline):
and the loss function is
What is the optimal fiscal policy that the government should pursue when its objectives are to reduce inflation by two points without changing the level of output,if the central bank does not change monetary policy?What is the value of the loss function? c.Assume nOW that the central bank decides to cooperate.What is the optimal policy mix?What is the value of the loss function?
一台三相绕线转子异步电动机,额定数据为PN=l6kW,ULN=380V,定子绕组Y联结,电动机拖动恒转矩负载TL=0.7TN在固有机械特性上稳定运行。当突然在转子电路中串入三相对称电阻R=1Ω求:
(1)在串入转子电阻瞬间电动机产生的电磁转矩:
(2)电动机稳定运行后的转速n、输出功率P2、电磁功率PM及外串电阻R上消耗的功率
(3)在转子串入附加电阻前后的两个稳定状态下,电动机转子电流是否变化?
A.电动机定子绕组或转子绕组断路
B.电磁抱闸线圈断路
C.滑触线与集电环接触不良
D.凸轮控制器主触头接触不良