SIGNAL CONVERTER AND MOTOR DRIVE SYSTEM

To provide a signal converter and a motor drive system which can switch the operational state of a control target by using a supplied signal.SOLUTION: The signal converter includes: a first signal input terminal 381, to which a first AC signal is supplied from a signal source; a second signal input terminal 384 including an in-phase signal in phase with the first AC signal and an opposite-phase signal in opposite phase to the first AC signal, to which a second AC signal is supplied from the signal source, the phase of the second AC signal having been switched by a switch between the in-phase signal and the opposite-phase signal; and a detector 34 for determining whether the supplied second AC signal is the in-phase signal or the opposite-phase signal by using the supplied first AC signal.SELECTED DRAWING: Figure 1 【課題】供給される信号を用い、制御対象の稼働状態を切り替えることができる信号変換装置、及びモータ駆動システムを提供する。【解決手段】信号変換装置は、信号源から第１交流信号が供給される第１信号入力端子３８１と、前記第１交流信号と同相の同相信号と前記第１交流信号と逆相の逆相信号を含み、前記同相信号と前記逆相信号の切り替えにより位相が切り替えられた第２交流信号が前記信号源から供給される第２信号入力端子３８４と、前記供給された第１交流信号を用いて、前記供給された第２交流信号が前記同相信号か前記逆相信号かを検出する検出部３４と、を備える。【選択図】図１