Iron losses are considered to be the constant losses. It depends on

Copper losses in a rotating machine are

A. Variable losses

B. Constant losses

C. Both (a) or (b)

D. None of these

Stray losses are the losses which vary with the load but their relationship with load current cannot be identified. Stay losses is maximum in

A. Synchronous machines

B. D.C. machines

C. Induction machines

D. Equal in all types of machines

The brush contact losses in a d.c. Machine is

A. Inversely proportional to the square of current

B. Directly proportional to the square of current

C. Inversely proportional to the current

D. Directly proportional to the current

Electrical power output in a d.c. generator is equal to

A. Electrical power developed in armature – copper losses

B. Mechanical power input – iron and friction losses

C. Electrical power developed in armature – iron and copper losses

D. Mechanical power input – iron and friction losses – copper losses

Mechanical power developed in armature of a d.c. motor is given by

A. Electrical power input to motor – copper losses

B. Motor output + iron and friction losses

C. Both (a) & (b)

D. None of these