单选题 "380V/220V Y/△" noted on the nameplate of a non-synchronous motor means that _____.
A、the armature terminals of the motor should be connected in star formation when voltage of power supply is 380 V
B、the armature terminals of the motor should be connected in delta formation when voltage of power supply is 220 V
C、both A and B are correct
D、the armature terminals of the motor should be connected in reverse ways of A and B
单选题 What type of electric motor is most commonly used on board ship?
A、Non-synchronous electric motor.
B、Synchronous electric motor.
C、Fully enclosed electric motor.
D、Watertight electric motor.
单选题 The main body of the induction motor comprises of two major parts .
A、magnetic field and winding
B、stator and rotor
C、exciter and armature
D、motor and stator
单选题 A transformer in an electric circuit serves to _____.
A、generate its own electrical power
B、transform electrical energy into mechanical energy
C、increase or decrease circuit voltage as required
D、convert AC current to DC current
单选题 In an automatic control system ________changes the signal received from the detector or sensor into some readily amplified output, usually electrical.
A、receiver
B、transmitter
C、controller
D、an amplifier
单选题 Reduced voltage applied to a motor during the starting period will ______.
A、result in decreased acceleration time only
B、lower the starting current and increase accelerating time
C、cause a greater starting torque
D、increase the starting current and pump capacity
单选题 The nameplate of a AC non-synchronous motor shows that running speed is 1460 r/min, frequency 50 Hz. You can infer that the number of magnetic poles is _____.
单选题 Control system theory can be broadly broken up into two major categories:__________.
A、automatic control and manual control
B、open loop control and closed loop control
C、hydraulic control and electrical control
D、pneumatic control and hydraulic control
2026-07-07
共139道
