A. 0.07
B. 1.5
C. 2.5
D. 3.5
Correct Answer: 0.07 ✔
Last Updated: December 22, 2018
Related MCQs
- Which of the following is an advantage of hydrogen cooling ?
- The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ?
- The noise produced by a __________ cooled machine is less as the rotor moves in a medium of smaller density?
- The thermal conductivity of hydrogen is __________ times that of air?
- cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall__________?
- With conventional hydrogen cooling it is possible to increase the rating of a single unit to__________?
- Hydrogen has a heat transfer co-efficient __________ times that of air?
- Multiple inlet system of air cooling of turbo-alternators can be used for machines of rating upto__________?
- The mcrease in heat dissipation by air blasts is due to increase in__________?
- On which of the following variables heat convected depends ?
- Which of the following materials is used in the manufacture of resistance grids to be used in the starters of large motors ?
- The heat dissipated by from a surface depends upon its temperature and its characteristics like colour, roughness etc?
- __________is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ?
- Aluminium when adopted as a conductor material in __________ transformers, decreases the overall cost of the transformer?
- Hot rolled sheets have __________ value of permeability?
- Materials exhibiting zero value of resistivity are known as __________ ?
- __________is universally used for windings of electrical machines because it is easily workable without any possibility of fracture?
- __________ has a low relative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable?
- Commercial available medium size machines have a speed range of __________ ?
- The change in flux linkages can be caused in which of the following ways ?
- The action of electromagnetic machines can be related to which of the following basic principles __________?
- The length cf air gap to be provided in __________ is primarily determined by power factor consideration?
- The design of mechanical parts is particularly important in case of __________ speed machines?
- impose limitation on design__________?
- If an insulating material is operated beyond the maximum allowable temperature, its life is__________?
- Electrical machines having a power output up to about 750 W may be called__________machines?
- In induction motors, the length of air gap in kept as small as mechanically possible is order to have__________?
- Which of the following is the major consideration to evolve a good design ?
- The efficiency of a machine should be as __________ as possible to reduce the operating cost?
- Electrical machines having power outputs ranging from a few kW up to approximately 250 kW may be classified as__________?
- In _________ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft?