| 摘要 |
PURPOSE:To prevent the operation of a drive device for a motor from becoming unstable by providing an upper limit of duty by a control arithmetic circuit and stopping the counting of the rotating speed when it exceeds the upper limit of the set duty. CONSTITUTION:A controller for frequency converter has a control circuit 23 which includes an arithmetic memory. This control circuit 23 stops the output of the converter by the rotating speed count command from a rotating speed measurement instructing circuit 26 and calculates the rotating speed from the induced voltage of a motor 5, and the result is temporarily stored in the memory. The upper limit of the duty is provided in the control circuit 23, and when it exceeds the upper limit of the set duty, the measurement and calculation of the rotating speed are stopped. |
