更多"In an alternating current electrica"的相关试题:
[单项选择]The alternating current generator supplying a load has a voltage drop resulted from the loadWhen the load has a lagging power factor this voltage drop （）.
A. is small
B. may be neglected
C. is useful
D. is considerable
[单项选择]The frequency of the alternating current generated by a synchronous generator is governed by the speed and the（）
A. full excitation
B. load
C. power factor
D. number of poles
[单项选择]The refrigeration system low pressure cutout switch is actuated by （）.
A. an electric system manager
B. a sensing bulb at the tail coil of the evaporator
C. pressure changes in the suction line
D. failure of the king solenoid valve
[单项选择]The purpose of the refrigeration system low pressure cutout switch is to （）
A. protect the compressor from liquid flood back
B. protect the compressor from low discharge pressure
C. start and stop the compressor upon system demand
D. start the compressor after a drop in the evaporator pressure
[单项选择]In an operating refrigeration system low on refrigerant, a liquid line sight glass will（）
A. be clear
B. be blue
C. be light green
D. show bubbles
[单项选择]A switchboard for an AC electrical system requires the use of which of the following devices（）.
A. Frequency meter
B. Ohmmeter
C. Induction voltage regulator
D. Current transformer governor
[单项选择]The part of the shipboard electrical system used to control the distribution of power to the branch circuits, is the （）.
A. bridge control panel
B. disconnect links
C. governor relay box
D. main switchboard
[单项选择]In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）
A. broken valve springs
B. tight drive belts
C. high line voltage
D. air in the system
[单项选择]The low pressure side of a refrigeration system is considered to exist from the （）.
A. expansion valve to the compressor
B. receiver to the expansion coil
C. expansion valve to the evaporator
D. condenser to the expansion valve
[单项选择]Compared to a low pressure system，generally the air in a high is（）.
A. warmer，less dense，and less stable
B. cool，more dense，and drier
C. muggy and cloudy
D. extremely moist with high relative humidity
[单项选择]The passing of a low pressure system can be determined by periodically checking the（）.
A. Thermometer
B. Hygrometer
C. Barometer
D. Anemometer
[单项选择]The system will include various （） such as low tank level alarms and remote operation of tank outlet valves in the events of a fire.
A. Switches
B. panels
C. alarm units
D. safety devices
[单项选择]An alternating light（）.
A. shows a light with varying lengths of the lighted period
B. shows a light that changes color
C. marks an alternate lesser-used channel
D. is used as a replacement for another light
[单项选择]Windows2003系统禁止匿名用户连接应修改注册表键值，将HKLM＼SYSTEM＼CurrentControlSet＼Control＼Lsa里（）的值修改为“1”，类型为REGDWORD。
A. restrictunnameuser
B. restrictanonymous
C. denyunnameuser
D. denyanonymous
[单项选择]Electrical circuits are protected against overheating by means of a/an （）.
A. circuit breaker
B. amplifier
C. diode
D. capacitor
[名词解释]电气设备（electrical equipment）
[单项选择]Electrical power is expressed in （）
A. ohms
B. volts
C. amps
D. watts
[单项选择]The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is the（）.
A. loss of residual magnetism
B. absorption of moisture in the insulation
C. insulation varnish flaking
D. dirt collecting on the windings
