So how does a portable generator work? Well it’s best to start at the beginning. A Portable Generator basically consists of a power generator head, an engine, a fuel source and . For this reason, they are sometimes known as an engine-generator set, or a gen-set by some people. That description is its simplest form and an explanation of how they work separately and together follows.
read it here: http://www.generatorgrader.com/portable-generator-work/