The low speed permanent magnet alternators are the main source of power generation at very low speeds and hence these are invariably used for all Renewable Energy system drives and require special design for each application and speeds. These alternators are provided with (Nd-Fe- B) Neodymium permanent magnets of high intensity energy hence high power output and long life so that the alternators are of compact design even at low speeds. VET PMGs are available from 0.10 kW up to 100 KW. The range of low speed PMG is from 50 rpm upto 3000 rpm and above. For range of rpm from 1 to 50 rpm PMGs are available with gearbox.