Which of the following statements are correct in a DC machine, when the pole core is usually of smaller cross section than the pole shoe?(i) smaller cross section requires less copper(ii) larger pole shoe increases the air gap reluctance(iii) larger pole shoe increases the flux per pole entering the armature(iv) larger pole shoe reduces the mechanical strength(v) larger pole shoe supports the field winding

Rotating electrical machines convert electrical power into mechanical power.  They are used in many sectors, including: Mechanical engineering Plant construction Chemical, oil, and gas industries Energy and environmental engineering Wind power plant construction Transport engineering Steelworks and rolling mills Ship-building  Rotating electrical machines are made up of a stator, rotor, and an air gap between them. The stator and rotor have windings that carry electrical current to generate magnetic fields for the electrical load. The windings can also generate closed loops for... Show more

Rotating electrical machines convert electrical power into mechanical power. 

They are used in many sectors, including:
Mechanical engineering
Plant construction
Chemical, oil, and gas industries
Energy and environmental engineering
Wind power plant construction
Transport engineering
Steelworks and rolling mills
Ship-building 

Rotating electrical machines are made up of a stator, rotor, and an air gap between them. The stator and rotor have windings that carry electrical current to generate magnetic fields for the electrical load. The windings can also generate closed loops for voltages. 
There are two types of rotating electrical machines: DC and AC machines. In DC machines, the stator is used as a field and the rotor is used as an armature. In AC machines, the rotor always carries alternating current (AC), while the stator can carry alternating current (AC) or direct current (DC). 

Some examples of rotating electrical machinery include: Electric motor, Electrical generator, Motor-generator, Rotary transformer. 
 

Related Test: Electrical Machines Practice Test: Basic Concepts in Rotating Machines 

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