37.5-inch rotary table

The rotary table turns the kelly on a rig that does not drill with a top drive, and it supports the slips while tripping on either kind of rig. The 37.5-inch figure is the opening through the table. Independent drive means the table has its own motor, rather than a mechanical drive from the drawworks. “ZP 37.5” on a rig list is that opening. It is not, by itself, one manufacturer’s model.

It fits a floor and a master bushing built for a 37.5-inch opening. Load and speed are whoever built the table. NOV’s published machine in this opening is the RST-375 hydraulic rotary support table: 750 short tons static, 15 rpm intermittent, 5 rpm continuous, 3,000 psi hydraulic, and about 14,102 pounds. Use that as a picture of the class. Another maker’s 37.5-inch table can be rated differently. The nameplate is the rating.

A 27.5-inch table is the smaller opening and will not take a 37.5-inch bushing or slip body. A top drive does not remove the need for a table if you still set slips in the rotary, but it does remove the need for the table to turn a kelly. Independent drive and a kelly drive from the drawworks are different installations.

Get the maker, the static load, the maximum rpm, and the master-bushing size. Ask if the drive motor and gearbox are included. The opening only tells you which bushing and which slip body can fit. It does not tell you how much string the table will hold.