| 摘要 |
PURPOSE:To rotate a motor at the same rotating speed even in both power frequency is 60 or 50Hz by converging the rotating speed degree to a reference signal by a phase comparator. CONSTITUTION:A phase comparator 6 inputs a referece signal (a) and an output signal (b) from a waveform shaper 5, and outputs a phase delay signal (c). An adder 8 compares the signal (c) with a DC voltage (d) in response to the rotating speed from a speed detector 7, and outputs a difference signal (f). A triangular wave (e) from a triangular wave generator 9 is compared by a comparator 10 with the signal (f), and the comparator 10 outputs a signal (g) of high level when the signal (f) is larger than the wave (e). A triac 3 is turned ON by the signal (g). |
