THE DESIGN OF 1 N•M TORQUE STANDARD MACHINE AT NIM

Abstract

A 1 N•m torque standard machine has been designed and developed at National Institute of Metrology (NIM) since 2011. The torque standard machine adopts the moment arm-deadweight type, the air bearing with low friction is adopted to support the moment-arm at the fulcrum, the invar with the low expansion coefficient is used as the material of the moment-arm, the weight suspension part and weight loading system are specially designed to ensure the applied force by small weights accurately and reliably. This paper introduces the mechanical structures of the machine, the electrical control system is described. 1 N•m torque standard machine is capable of realizing the torque from 1 mN•m to 1 N•m both in clockwise and anti-clockwise directions.