| 摘要 |
PURPOSE:To effectively accelerate slowly a centrifuge by providing a mixed bridge which has a phase controller, a rectifier of two thyristors and two diodes and switching between half-wave phase control and half-wave rectification at the slow accelerating time of a motor. CONSTITUTION:A mixed bridge circuit is composed of two thyristors and two diodes 7, thereby controlling the DC motor 3 of a centrifugal machine. A rotating speed detector 4 detects the rotating speed of the motor 3, applies it to a gate controller 8, which outputs a gate signal to a thyristor 6. When the motor 3 is slowly accelerated, one of two thyristors 6 is idled, the mixed bridge circuit is controlled in half-wave phase and operated in half-wave rectification. After the motor 3 reaches the prescribed speed, it is controlled in full-wave phase and operated in full-wave rectification. In this manner, even if the waveform of the power source is deformed, the motor can be effectively slowly accelerated. |
