The correct answer is: D. Iron loss and mechanical loss.
Stray loss is a type of loss in a D.C. machine that is not easily categorized as either copper loss or iron loss. It is caused by a variety of factors, including eddy currents, hysteresis, and radiation. Stray loss is usually a small percentage of the total loss in a D.C. machine, but it can be significant in some cases.
Copper loss is the loss of power due to the resistance of the windings in a D.C. machine. Iron loss is the loss of power due to the magnetic properties of the iron core in a D.C. machine. Mechanical loss is the loss of power due to friction and windage in a D.C. machine.
Stray loss is not included in either copper loss or iron loss because it is not caused by either of those factors. It is a separate type of loss that is caused by a variety of factors.
Here is a more detailed explanation of each option:
- Option A: Total copper loss and mechanical loss. This is not the correct answer because stray loss is not included in total copper loss.
- Option B: Armature copper loss and iron loss. This is not the correct answer because stray loss is not included in armature copper loss or iron loss.
- Option C: Shunt field copper loss and mechanical loss. This is not the correct answer because stray loss is not included in shunt field copper loss or mechanical loss.
- Option D: Iron loss and mechanical loss. This is the correct answer because stray loss is a type of loss that is caused by the iron core and mechanical components in a D.C. machine.