In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made

Related MCQs

• In D.C. machines, the ____ in field mmf results in increase in size and cost of machines.
• Which of the following methods may be adopted to reduce the effects of armature reaction ?
• cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall
• The weight of copper of both armature and field windings decreases with _____ in number of poles.
• ______ brushes are fragile and cause excessive wear of commutator,
• The laminations of the armature of a D.C. machine are usually _____ thick.
• The design of mechanical parts is particularly important in case of _____ speed machines.
• In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft.
• Electrical machines having a power output upto about 750 W may be called_______machines.
• Electrical machines having power outputs ranging from a few kW upto approximately 250 kW may be classified as