Establishment and Development of Torque Metrology in CSIR-NPL for Providing the Traceability in Torque Measurements to User Industries

Torque primary standard machines are established at CSIR-NPL, India to realize the torque scale and to disseminate the same for user industries for providing the traceability in torque measurement. Two torque machines, a primary standard machine comprising of elastic hinge supported load lever with scale pan having an uncertainty of ±0.01 % and a secondary standard machine comprising of an unsupported lever arm with a scale pan suspended by a knife edge having an uncertainty of ±0.05 %, are established. The uncertainty of these machines are estimated theoretically by considering the uncertainty contributions of various input quantities which is also reaffirmed through the inter-comparison carried out on these machines.