It is always good to see the success stories but there are times when I haven't had any idea if my comments have helped. It is nice to see that some of the comments are from people that I don't ever remember replying to directly.

That is one reason I don't mind answering similar questions, firstly it is quicker than searching to find a previous reference and secondly a reference would most likely only help the person who asked the question.

Yes I am old and grey and although I am not an engineer I spent many years in heavy electrical industry. I have played with wind power since I was about 10 and it is good to see input from young people on this board, with the internet things are easier for them and starting young is much better when you learn quickly.

When I started we only had dynamos with brushes and commutators, the selenium rectifiers of the day were almost useless for alternators and the magnet steels were very poor.

I have always kept an open mind on early developments that most have forgotten, with new materials the problems that caused their demise can often be overcome.

The air gap alternator was one of the earliest, by Ferranti and others and now with neo magnets we can make good use of it. Industry went down the other route with iron cores and slotted teeth as it was the best way with wound fields but is easier to remember the early ideas rather than re-invent them.

When I was young I thought authors of books were gods and could not be approached so I was surprised to find that Hugh Piggott does not fit this category and is prepared to help anyone, I have learned a lot from him and if I can help others as well I am happy to do so.

I must also express my gratitude to the Dans for operating this site and making all their knowledge public and allowing us to share our knowledge here.

I am often amazed at peoples determination to make things work even though their background is obviously in very different fields.

Just one final point, the main problem with solving problems from a distance is lack of information so if I keep asking more questions it is because I need to know more to give a sensible answer.