What Does
Rotary Table Mean?
A rotary table is the revolving plate on the rig’s drill floor that turns the drill string in a clockwise direction. The rotary table surrounds the four or six-sided kelly bushing and kelly drive to which the drill string is attached, transferring the power from the rig’s drive system to the drill string and bit.
May also be referred to as the clutch.
Trenchlesspedia Explains Rotary Table
Because the rotary table links the rig’s power source to the drill string, it may be described as a clutch. Most rigs have a rotary table as the prime mover for the drill string, however, top drive systems that permit continuous rotation of the drill string have replaced the rotary table, the kelly bushing and the kelly drive in some rigs, due to changes in trenchless construction requirements.
The rotary drive table is prevalent in top-drive rigs, that is, those which have their drive motor at the top of the rig. Drill string sections are first attached to the bottom hole assembly. As drill string sections go into the bore, additional sections of drill string are attached to the top drive motor and to sections in the bore, building the drill string from the top. These sections of drill string screw together using a clockwise motion. The rotary table — which turns clockwise — is used to tighten the segments of the drill string.