NOV TDS-11SA top drive

A top drive hangs in the derrick and turns the drill string from the top. The crew can drill, circulate, and make a connection without a kelly. The TDS-11SA is the 500-ton portable AC drive that became the common land-rig top drive. NOV rates it at two 400 horsepower motors, 800 horsepower combined, and 37,100 ft-lb of continuous torque.

It fits a land mast built for a 500-ton load path and enough clear height for a drive with a published working height of 17.8 feet and a weight of about 27,000 pounds. The pipe handler is a PH-75. Links are published at 250, 350, and 500 tons, and the links have to match the load you will pull. A 750-ton mast that was built around a TDS-8 is a different installation.

The TDS-11SH and TDS-11HD keep the 500-ton hoisting rating and add torque: 54,600 ft-lb on the SH and 58,800 ft-lb on the HD. A TDS-10SH is the smaller 250-ton drive. Later kits, including the TDS-11SAE and the TDS-11-1400, raise the horsepower of an existing SA. A drive with those motors is no longer a stock 800 horsepower TDS-11SA, even if the housing looks the same.

Read both motor nameplates. Hoisting capacity, continuous torque, and horsepower are three different ratings, and upgrade kits change the last two. Confirm the PH-75, the 15,000 psi IBOPs, and the bail length, because those decide which links fit and whether the derrick has room. The brochure lists continuous torque at 125 rpm. The SA flyer lists the same 37,100 ft-lb at 110 rpm. Use the data book that matches the serial number.