单选题Universal motors will operate on AC or DC current, and are generally found in （）Aportable toolsBlarge pump motorsCturbo electric main motorsDforced draft fans
单选题
Universal motors will operate on AC or DC current, and are generally found in （）
A
portable tools
B
large pump motors
C
turbo electric main motors
D
forced draft fans
参考解析
解析：
暂无解析
相关考题：
Diesel engine electric starting motors generally require heavier duty motors and motors and operate at higher voltages than comparable starting motors for gasoline engines due to _____________.A.higher speed requiredB.flywheel-effectC.lower starting temperaturesD.higher compression pressures
An advantage of DC motors over AC motors is that they______.A.are less expensiveB.require less maintenanceC.can be started across the lineD.offer a more effective means of controlling speed
在线式UPS一般为双变换结构，所谓双变换是指UPS正常工作时，电能经过了（）两次变换后再供给负载。A、DC/AC和DC/ACB、AC/DC和AC/DCC、DC/AC和AC/DCD、AC/DC和DC/AC
基本变压整流器（ESS TR）有哪几个供电来源？（）A、AC BUS1，AC BUS2。B、ECMU1；ECMU2。C、DC BAT BUS；DC ESS BUS。D、AC BUS 1；AC BUS 2；CSM/G。
单选题The purpose of DC generator brushes is to （）.Aneutralize armature reactionBconduct electric current to an outside circuitCconvert DC current to AC currentDprovide excitation to a DC generator
单选题A DC generator is used to supply direct current in order to maintain an AC generator field and is known as a/an （）ArotorBstatorCexciterDarmature
单选题Diesel engine electric starting motors generally require heavier duty motors and motors and operate at higher voltages than comparable starting motors for gasoline engines due to（）Ahigher speed requiredBflywheel-effectClower starting temperaturesDhigher compression pressures
单选题An advantage of DC motors over AC motors is that they （）Aare less expensiveBrequire less maintenanceCcan be started across the lineDoffer a more effective means of controlling speed
单选题The purpose of the commutator and brushes on a DC generator is to（）Achange AC to DCcurrentBchange DC to AC currentCneutralize a armature reactionDcarry current to the outside circuit
单选题When two DC generators operate in parallel, they are protected against motorizing by（）Ablow out coilsBgovernor relayCunder voltage tripsDreverse current trips
单选题A transformer in an electric circuit serves to （）Agenerate its own electrical powerBtransform electrical energy into mechanical energyCincrease or decrease circuit voltage as requiredDconvert AC current to DC current