The line then exits the last sheave on the crown block and is fastened to a derrick leg on the other side of the rig floor.
The apparatus can be powered by electricity (AC or DC), or the drawworks may be connected directly to internal combustion engines using metal chain-like belts.
This brake may use eddy current rotors or water-turbine-like apparatus to convert the kinetic energy of the moving load to heat and dissipate it.
Power catheads (winches) located on each side provide the means of actuating the tongs used to couple and uncouple threaded pipe members.
The drawworks is used to hoist or lower several hundred thousand pounds of weight and comes in AC, DC or mechanical power units.