respirator vs breathing machine

respirator and breathing machine both are nouns.

Word	Noun	Adjective	Verb	Adverb
respirator	Yes	No	No	No
breathing machine	Yes	No	No	No

As nouns, breathing machine is a hypernym of respirator; that is, breathing machine is a word with a broader meaning than respirator:

respirator: a breathing device for administering long-term artificial respiration
breathing machine: a device that facilitates breathing in cases of respiratory failure

Other hypernyms of respirator include breathing apparatus, breathing device, ventilator.

respirator (noun)	breathing machine (noun)
a breathing device for administering long-term artificial respiration	a device that facilitates breathing in cases of respiratory failure
a protective mask with a filter; protects the face and lungs against poisonous gases