Patent ID: 7575372

Claim:
A device for measuring temperature of a rotatable rotor ( 201 , 202 ) that cooperates with a stator, the device comprising an electric coil ( 205 , 206 ) arranged on the stator; a permanent magnet ( 204 , 302 ) mounted on the rotor ( 201 , 202 ) for rotation therewith for inducing voltage in the electric coil ( 205 , 206 ) upon passing the electric coil ( 205 , 206 a ); and electronic means for measuring the voltage ( 207 , 405 ) induced in the coil ( 205 , 206 ) by the permanent magnet ( 204 ) and including means for converting the voltage into a temperature-proportional signal, wherein the operating temperature of the magnet ( 204 ) lies within the temperature range in which a dependency of magnetization on temperature is linear and reversible.