| 摘要 |
PURPOSE:To detect the excess speed of the rotating speed of a motor with a simple circuit configuration by positively or negatively inverting a pulse signal of an encoder, and obtaining the excess speed detection signal by the logic product of the pulse signals generated by the normal or reverse signal. CONSTITUTION:A pulse signal of the period in response to the rotating speed of an encoder 2 is output from a photoreceptor 4, and a frequency divider 11 generates an output signal divided in frequency by 2 synchronously with the rise of the signal. One shot multivibrators 12, 13 generate signals S1, S2 of pulse width tau synchronously with the rise of the signal of the output terminal of the divider 11. When the rotating speed of the motor 1 is accelerated, the signals S1, S2 are partly superposed to become a high level at the partly superposed zone, and an AND circuit outputs an excess speed detection signal S3. |
