| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a DC motor rotation speed detector which can be simplified and compactified, without necessity of providing a signal line for a special cable in the case of controlling a brushless DC motor, using a rotation speed signal. <P>SOLUTION: This DC motor rotation speed detector consists of a controller 1 which includes a DC power source 14 for a DC motor 16 and a control circuit for controlling it. The drive of the DC motor is controlled by the controller 1. The controller 1 is provided, within itself, with a rotation speed detecting circuit comprising a current-voltage converting circuit 2 which converts the full current waveform of a current supplied from the power source 14 for the DC motor, an AC amplifying circuit 3 which amplifies the AC of the output signal of the current-voltage converting circuit 2, and a comparator circuit 4 which compares the output signal of the AC amplifying circuit 3 with preset threshold voltage. This detector can detect the rotation speed even in condition that the DC motor 16 is in a wide range of load state, and also this does not need a special cable for transmission of a frequency signal, and the configuration can be simplified and compactified. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
