| 摘要 |
PURPOSE: To change over to position detection operation from synchronous operation at the time of starting surely. CONSTITUTION: In the condition of synchronous operation performed by increasing the voltage and the frequency of inverter output at the time of starting, a V/F pattern setting section 44 outputs a voltage command signal to a PWM section 54 to lower the inverter output voltage, when a potential difference signal level judging section 41 judges that a potential difference signal is not at a specified level, or when the comparison result of a mode comparing section 43 represents that a positional signal and an inverter mode do not have a constant relation. While, a position detection operation switching section 42 switches an operation changing switch SW from a synchronous operation side over to a position detection operation side, receiving a judgment signal from the potential difference signal level judging section 41 and a signal representing the comparison result from the mode comparing section 43, when the potential difference signal level judging section 41 judges that the potential difference signal is at the specified level, and the potential signal and the inverter mode have a constant relation in addition. |
