Stuska Water Brake
Water brake dynamometers are similar to a centrifugal pump or a torque converter. A rotor is turning inside a stator housing. Water is introduced creating friction and heat with torque being applied to the stator. The stator would spin with the rotor except the stator is anchored with a torque arm and a load cell. The torque that is being loaded gets transmitted through the torque arm and into the load cell that measures the force. The amount of heat generated is directly proportional to the power being absorbed. The water brake is convenient because the water that creates the load also carries away the heat as it is discharged from the brake.