| 摘要 |
PURPOSE:To enable to detect the temperature rise of a coil accurately in a short time by measuring resistance values of coils of a stator and detecting the temperature rises of coils by the variations in the resistance values. CONSTITUTION:A bridge is composed of coils 2 of a stator and resistors 10, 11, 12. Assume that the resistance of the coil 2 is RL, the resistance values of the resistors 10, 11, 12 are respectively R10, R11, R12, there arises a relationship of RL.R11=R10.R12 when the coil 12 is in reference temperature state. On the other hand, when the temperature of the coil 2 rises to the reference temperature or higher, the resistance value RL increases. Accordingly, the output voltage of an amplifier 13 corresponding to the coil 2 which is raised at the temperature increases. The outputs of amplifiers 13 are respectively connected to one input terminals of comparators 15 through diodes 14, and an alarm signal is outputted from the output terminal of the comparator 15 when the output of either amplifier 13 becomes the reference voltage E0 or higher. |
