CF1 (CF2) main circuit

The AC voltage is rectified by a bridge (VD1-VD4). 3R1 limits the current and reduces the voltage, and VD5 clips to form a trapezoidal wave, which is used as the DC
and synchronization voltage of the trigger circuit. When the base of VT1 receives the forward voltage of RP1, it is turned on. The collector is directly coupled to the base of VTZ. VT2 acts as a variable
resistor to change the charging time constant of the capacitor 3cl. When VT2 is connected, its collector charges 3 cl. When the charging voltage
Uc ≥ Up (peak voltage of the single-junction transistor), the resistance between e and bl of VT3 drops sharply and turns to conduction, and the emitter The current suddenly
increases and the capacitor 3G is discharged through 3Ra, then bl of VT3 has a sharp pulse output.
    Since the pulse amplitude output by bl is too small, it is amplified by VT4 and output by the pulse transformer Mr
- connected to G and K of VS1, triggering VS1 to turn on, when Ue <Up.
The blocking state is restored between VT3e and bl .
    7) Control main circuit and relay control circuit: The main control circuit adopts single-phase AC
220V power supply. After being phase-shifted by the phase-shifting capacitor cl, it is connected to a three-phase asynchronous motor. As
shown in Figure 2-39. Bal and series resistors act as resistance-capacitance protection for VS1 and VS2. Capacitance Ci can be
calculated according to the following empirical formula.