For faculty positions that require three years of research experience excluding PhD, how is that time calculated?
According to recent notification from UGC, research experience during PhD can also be included for teaching post.

Specially, in a notice dated 1 March 2016, it says:


  The issue regarding counting of the period of active service spent on pursuing Ph.D. was considered by the UGC in its 512th Meeting held on 4th February, 2016.
  
  The clarification of University Grants Commission is as follows:
  
  "the period of active service spent on pursuing Research Degree i.e. for
  acquiring Ph.D. degree simultaneously without taking any kind of leave may be counted as teaching experience for the purpose of direct
  recruitment/promotion to the post of Associate Professor and above."