Abstract:

A quick electrical calibration scheme is proposed to address the low efficiency and consistency of thermal overload relay calibration.The equivalent step ped current method is adopted.The first-step high current enables the bimetal strip to bend quickly.The second-step current tends to stabilize the bend of bimetal strip to eliminate the thermal inertia.When the third-step current ends, the bimetal strip reaches the preset position and maintains for a short while, then the product will be twisted to trip.In addition, corresponding validation and empirical parameters are provided in terms of component consistency, assembly process consistency, and parameters for quick electrical calibration.The proposed scheme can not only significantly improves production efficiency, but also effectively ensurs the consistency of components and processes, guaranteeing the stability of product performance.

Key words: thermal overload relay, quick electrical calibration, step current, bimetal strip