Toyota Lucida Alternator Problems

2 2 diesel lucida was running great but on tick over on my drive it just cut out and now won't start .at first thought it was lack of fuel but it's pumping through ok .as it's turning over there is some engine rock but not much ' checked fu...

My Lucida cut out on tick over and thought I had run out of fuel "added diesel and primed but now spinning to fast and alternator only giving out 11 volt's .was going to change it before the engine cut out .is this a snapped belt or coul...