On a drilling rig, the rotary table is a mechanical device located at the rig floor that provides rotational force to the drill string during drilling operations. It is a key component of the rig's rotating system and plays a crucial role in the drilling process. Here are the key features and functions of a rotary table: Rotational Power: The rotary table is driven by a power source, such as an electric motor or a diesel engine, which generates rotational force. This force is transmitted to the drill string via the kelly and the swivel, allowing the drill bit to rotate and penetrate the rock formations. Support for the Drill String: The rotary table provides support and a stable platform for the drill string. It is designed to handle the weight of the drill string, drill tools, and bottom hole assembly, transferring the load to the rig's structure. Connection Point for the Kelly: The rotary table has a central opening where the kelly is inserted. The kelly is a square or hexagonal pipe that extends downward from the rotary table and transmits the rotational force to the drill string. The kelly is connected to the rotary table via a square or hexagonal kelly bushing, which securely holds the kelly in place while allowing rotational movement. Speed and Direction Control: The rotary table allows the driller to control the rotational speed and direction of the drill string. The power source driving the rotary table can be adjusted to achieve the desired rotation speed, which depends on factors such as the formation being drilled and the drilling technique being employed. The driller can also change the direction of rotation as needed during drilling operations. Safety Features: The rotary table incorporates safety features to protect personnel and equipment. These features can include guards and barriers to prevent accidental contact with moving parts, emergency stop mechanisms, and interlocks to ensure safe operation. It's important to note that the rotary table is one of the options for providing rotational force to the drill string. In some modern drilling rigs, a top drive system is used instead of a rotary table. The top drive is a motorized device that is suspended from the rig's derrick or mast and directly rotates the drill string without the need for a kelly or a rotary table. The choice between a rotary table and a top drive system depends on the rig's design, drilling requirements, and operational preferences. Overall, the rotary table is a fundamental component of the drilling rig's rotating system, enabling the rotation of the drill string and facilitating the drilling process.