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Variable speed high-power thyristor trigger circuit

Published on Apr 11 2011 // Motor Control circuits

General books and high-power thyristor trigger circuit described are complex, and some components is difficult to buy. I only spent a few dollars trigger circuit has been successfully produced more than 100A SCR trigger module for industrial quenching furnace 380V voltage regulator, but also installed a set of high-power variable speed blower for use, the effect is very good. The circuit is also used as a regulation of the 220V AC power supply with electrical appliances.

Variable speed high-power thyristor trigger circuit.

Circuit shown in Figure. The two-way thyristor SCRl, SCR2 reverse parallel. Then the control board and the trigger circuit connected to form a simple and practical high-power variable speed circuits. This circuit is unique in that most do not need external power supply thyristor control, as long as the load connected in series with the circuit power supply, two control between the electrode and the respective cathode there 5V ~ 8V DC voltage pulse generation, regulation potentiometer R2 to change the two SCR conduction angle, increasing the resistance R2 to a certain extent, would allow the two main silicon block, so R2 can also switch from the role. Another feature of the circuit is alternating two main thyristor conduction, a forward voltage drop is another of the reverse voltage drop, so there is no reverse breakdown problems. But when the applied voltage over blocking voltage transient, SCR1, SCR2 misleading pass, turn-level decision by the potentiometer R2. SCR3 common with the surrounding components, the phase-shift trigger circuit, the principle here omitted.
  SCR1, SCR2 I use the packaged SCR module (110A/1000V), SCR3 use BTl36, that is bi-directional SCR 600V. The circuit for inductive load, such as, should increase the R4, C3 RC snubber circuit and varistor RV for over voltage protection, load disconnect and connect instantly to prevent the generation of high voltage damage to the silicon sensor