Frequency converter speed regulating circuit with preamplifier box

Frequency converter is a new type of speed control device that has come out in recent years. Through the connection of external units, the frequency converter can expand its use functions to meet various technical requirements and practical needs. As shown in the figure, the external unit of Japan's Mitsubishi inverter, that is, the FR series operating box, setting box, preamplifier box, etc., as shown in the figure, is matched with the inverter to control the three-phase motor for speed regulation. The preamplifier box (FR-FA) can be used as a current/voltage signal conversion or operational amplifier. The linkage setting operation box (FR-AL) outputs the signal to the inverter, and then the inverter controls the motor M to achieve frequency conversion. Adjustable speed operation.