A substituent on Cyclohexane ring in the chair conformation,  usually  and generally can occupy__ position

Presence of groups at equatorial position decreases repulsions with the 3rd carbon.(note that in chair form alternate carbons are in one plane). Presence of any group at axial position will create repulsion with the 3rd carbon. This repulsion with C-1 and C-2 is called as syn 1,3 di-axial repulsions. Hence any group at equatorial will be repulsion free.