DSF-type air-cooled eddy current brake eddy current brake is used to adapt to the marine and land oil rig on a new type of auxiliary brake, which uses the principle of electromagnetic induction-free brake wear, with big torque, no wearing parts, long life operation maintenance of simple features. Application of eddy current brake can be a significant reduction of the main brake wear, brake with the extension of the life of wheel brakes to reduce the labor intensity of drilling workers, by changing the excitation current to regulate the brake torque to control the speed of the drill pipe decentralization. Speed to 50 to / time, up to 75% of maximum torque, fully able to meet the requirements of heavy-duty drilling under