Calibration of DC current up to 600A

DC large current ratio standard is developed, calibrating DC large current based on the principle of ampere-turn balance. Under the same equilibrium condition of ampere-turn, large current can be traced to the magnetic balance current, which is relatively small, easy to be calibrated. The consistency of magnetic balance current of each turn, the linearity of magnetic balance ratios and the accuracy of current transferring at the same flux should be taken into consider.