... driller control cabin, auto-bit-feeding system, unitized instrumentation, traveling block position control system and VF speed regulation ... 29.3)Note: DB AC VF drive rig drilling rig , drilling equipment ,drilling machine ,oil rig,oil equipment, rig equipment, ... land rig ,truck-mounted rig,mobile drilling rigrotary drilling rig truck-mounted drilling rig, Land Drilling Rigs,kazakhsatn rig ,russian rig, ...