disconnector vs distributor

disconnector

noun
  • A switching device used to open an electric circuit when there is no current through it. They are used to isolate a part of an electrical system to allow the maintenance staff a safe access to it. 

distributor

noun
  • A device that distributes electric current, especially to the spark plugs in an internal combustion engine. 

  • One who or that which distributes. 

  • A machine for distributing type. 

  • An appliance, such as a roller, in a printing press, for distributing ink. 

How often have the words disconnector and distributor occurred in a corpus of books? (source: Google Ngram Viewer )