Q.1
In a mercury arc rectifier, the anode is usually made of
Q.2
Selenium rectifier can be operated at temperatures as high as
Q.3
Which of the following is reversible in action?
Q.4
A rotary converter operates at a
Q.5
The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following
Q.6
In which of the following appUcations, direct current is absolutely essential ?
Q.7
In phase-shift control method the control is carried out by varying the of grid voltage.
Q.8
A mercury arc rectifier possesses ________ regulation characteristics
Q.9
The advantage of mercury arc rectifier is that
Q.10
The potential drop in the arc, in a mercury arc rectifier, varies
Q.11
The ionization potential of mercury is approximately
Q.12
Copper oxide rectifier is usually designed not to operate above
Q.13
In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as
Q.14
In selenium rectifiers efficiencies ranging from ______ to ______ percent are attainable
Q.15
The metal rectifiers, as compared to mercury arc rectifiers
Q.16
In a mercury arc rectifier positive ions are attracted towards
Q.17
The internal efficiency of a mercury arc rectifier depends on
Q.18
The ignited or auxiliary anode in mercury arc rectifier is made of
Q.19
In a glass bulb mercury arc rectifier the maximum current rating is restricted to
Q.20
A rotary converter in general construction and design, is more or less like
Q.21
Which of the following are the applications of D.C. system?
Q.22
Glass rectifiers are usually made into units capable of D.C. output (maximum continuous rating) of
Q.23
Which of the following AC. motors is usually used in large motor-generator sets?
Q.24
Ageing of a selenium rectifier may change the output voltage by
Q.25
In a rotary converter I2R losses as compared to a D.C. generator of the same size will be
Q.26
The cathdde voltage drop, in a mercury arc rectifier, is due to
Q.27
In a rotary converter armature currents are
Q.28
The applications of selenium rectifiers are usually limited to potential of
Q.29
The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?
Q.30
Which of the following methods may be used to convert A.C. system to D.C.?
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