High-torque motor speed control

Posted on Oct 15, 2012

A bridge circuit consisting of two SCRs and two silicon rectifiers furnishes full-wave power to the motor. Diodes, D3 and D5, supply dc to the trigger circuit through dropping resistors, Rl. Phase delay of SCR firing is obtained by charging C2 through resistors R3 and R4 from the voltage level established by the zener diode, D8. When C2 charges to the firing voltage of the unijunction transistor, the UJT fires, triggering the SCR that has a positive voltage on its anode

High-torque motor speed control
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When C2 discharges sufficiently, the unijunction transistor drops out of conduction. The value of Rf is dependent upon the size of the motor and on the amount of feedback desired. A typical value for Rf can be calculated 2.

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Carlos   May 31, 2022

what the components values for 220vac supply should be?

Dom44   Dec 27, 2021

I think there is a resistor missing from B1 to Ground about 100R

Omar   Sep 7, 2020

Dear, I could not make this circuit work !! Did you try it?

Thanks for your good suppor.    May 5, 2019

Dear sir Please you send AC generator AVR circuit diagram.

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