| 摘要 |
PURPOSE: To make it possible to transmit a detection signal from a temperature detector, by superimposing the detection signal as a modulation signal and transmitted through a DC power line. CONSTITUTION: A sine wave is generated from a sine-wave oscillator 17 according to a detection signal of a temperature detector that detects the temperature of a motor. The sine wave is modulated in amplitude. With a pulse transformer 13, a modulated signal is superimposed in DC power lines 12a and 12b for feeding DC power to an encoder unit 11 that detects a rotating state of the motor. The Superimposed modulated signal is demodulated in a demodulator circuit 17 to feed a detection signal from the temperature detector 15 to a control circuit 9. Then, low-pass filters 10 and 14 are put between the control circuit 9 and the encoder unit 11 to prevent an influence from the modulated signal. |
