i knew about mine....Sangwan gotra originated from the name of Raja Sangu...
Sangwan is a clan or gotra of Jats found in Rajasthan, Madhya Pradesh and Haryana in India. The present name of Sangwan Gotra came from Raja Sangram Singh or Sangu who came to Charkhi Dadri area in Haryana from Ajmer in Rajasthan after a long war between old khsatriya Jat Aryas and newly formed Rajput Kingdoms of Rajasthan.
this all i copied from sangwan's community....rest, i don't know about the origin of my other two gotras
and, i think all the history can be known from the wikipedia