The Villiers type 20 stationary engine was mainly used on Cement Mixers and Lawnmowers, etc., and dates back to the 1950's/60's.... this type of 12V 60Amp Alternator was mainly used on 1970's Landrovers, Tractors and Combine Harvesters, etc., as it has an internal voltage regulator with a remote "voltage sensing wire" which overcomes the "supply cable voltage drop" between battery and spot lights, keeping them nice and bright for running right through the night whilst getting the Harvest in!....