Development of a small capacity deadweight torque standard machine

The Korea Research Institute of Standards and Science (KRISS) has developed a 100 N m deadweight torque standard machine. The machine consists of a torque arm, an air bearing, six weight stacks, a main body and a control system. It can be operated almost fully automatically. The machine can generate torque from 0.1 N m to 110 N m with a relative expanded uncertainty of 5.0 x 10(-4) for 0.1 N m to 1 N m and 5.0 x 10(-5) for 1 N m to 110 N m. The machine was compared with a 2 kN m deadweight torque machine. In the comparison, the relative deviation was less than 5 x 10(-5), the declared expanded uncertainty of the torque standard machines, and therefore we confirmed the accuracy of the machine.