Patent ID: 6504358
Filing Date: 2003-01-07
Classification: G01K,G01R

Abstract:
A method for detecting a temperature of a starting motor with a still stationary rotor having a complex impedance with a real and an imaginary element, the method which comprises:determining values of a current and a voltage of the starting motor with the still stationary rotor; and determining a motor temperature of the starting motor with the still stationary rotor by determining a value of a real element R of a motor impedance of the starting motor with the still stationary rotor and comparing with a value of a real element R of a motor impedance which have been obtained at a known temperature, in which the real element R of the motor impedance is determined by the relationships R=U^22&it;P&it;(1+1-4&it;Ï‰2&it;L2&it;P2U^4)andL=L1&sgr;+Lâ€²2&sgr;from the measured values and known characteristic variables for the motor, whereÃ›=peak value of the voltage P=DC component of power L=inductance in a motor equivalent circuit L1&sgr;=inductance of a stator Lâ€²2&sgr;=inductance of a rotor, transposed to the stator &ohgr;=2&pgr;f.