文档介绍：第三章船舶电气与船舶安全
1886 The staring current of an . motor is ______the rated current.
交流电机的启动电流比额定电流大得多。 A. the same as B. much larger than C. less than D. equals
1887 Ammeter is to measure the ______安培表用来测量电流。
A. current B. voltage C. power D. frequency
In a modem three-phase . synchronous brushes generator, the excitation
winding is on the rotor. That means ______对于现代三相交流同步有刷的发电机,励磁线圈在转子上。意即转子上的线圈用于输入励磁电流。
A. The generator need not excitation
B. The winding on the rotor is for inputting excitation current
C. There are three phase windings on the rotor
D. The generator has brushes
1889 The over current relay ______ the motor contactor when the motor exceeds its rated current .当电动机超过额定电流时,过电流继电器将跳开。
A. connects B. trips C. fouls D. destructs
1886 B 1887 A 1888 B 1889 B
The ______ is a measure of the phase difference between voltage and current
and is expected as the cosine of phase ,表达成相位角的余弦。
A. power B. efficiency C. effective power D. power factor
1891 Current changing in direction and rising and falling in value is ______
方向、大小都变化的电流是交流电。
. . C. generator D. fresh water generator
1892 The operation of paralleling two alternators requires the voltages to be ______ and also in phase. 两台交流发电机并联,需要电压相等,并且同相。
A. zero B. eliminated C. different D. equal
1893 The ______ , cage rotor induction motor is the first choice marine motor in most modem ships because of its electrical and mechanical simplicity.
现代船舶上使用的电机都是三相电机。A. single phase B. two phase C. three phase D. four phase
1894 The star-delta starter is an effective method of ______ voltage starting of a —△启动器是电饥低电压启动的最好方法。
A. increased B. reduced C. unchanged D. None of the above
1890 D 1891 A 1892 D 1893 C 1894 B
With a ______ load the voltage and current are in phase.
对于纯电阻负荷,电压和电流同相。
A. purely resistance B. capacitive C. inductive D. None of the above
1896 Increasing the temperature of a fuel will ______ its viscosity.
提高燃油的温度将降低其粘度。 A. increase