Method and apparatus for transactional fault tolerance in a client-server system is described. While the device is stationary, sensor measurements at a current device temperature are used to estimate model parameters. At the attenuation pole frequency of the serial arm resonator, the resonating device functions as capacitance without performing attenuation. The values of the maximum and minimum current flowing through the winding insulation are determined, and the winding insulation resistance is calculated based on the difference between the maximum and minimum current.