Agreed. Laseredd: What do you think is necessary in explaining slip rings? Do you think it's necessary to mention that they are used to avoid tangling of wires which would happen if wires were used, or do you think saying that they don't change the current direction is sufficient?
I would vary my answer as according to the question and how many marks have been allocated. For VCAA 2010, the marks that would have been allocated to the slip ring portion (if I remember correctly, it asked what is the difference between the slip ring and the split ring commutator - pretty sure it was 3 marks)
My approach was something like:
- Split ring commutator is used in a generator, produces D.C.
- How it functions in a generator (alternates the contact every blah blah blah)
- Slip rings are used in an alternator (produces A.C.) and maintain the same contact with blah blah blah
As you can see, you run out of space to mention the tangling stuff. I would consider the facts mentioned there are more significant.
If it was a 3 mark question asking only about the function of the slip ring, then I would go ahead and mention the fact that it reduces entanglement. Probably look something like this:
- Slip rings are used in an alternator and produces A.C.
- How it does that (maintain the same contact with blah blah blah)
- Slip rings are used to prevent entanglement blah blah blah
If you go back and study the assessor reports, the entanglement reason seems to be a bit excluded.
edit: fixed formatting