Hello,

    I'm making a power voltage regulator using an autotransformer with various taps and SCRs to select the taps, but it's not working as expected.

    Please, take a look at http://www.citronics.com.br/brusque/SCR_SSR.png, this is the circuit of a Solid State Relay I'm using to select taps, like this:


    220V----------+---SSR1----)          note: the various ')' is
   input          |           )                the autotransformer
                  +---SSR2----)
                  |           )
                  +---SSR3----)
                              )
                              )
                              )-----120V
                              )     output
                              )
    GND-----------------------)-----GND

    Just for testing, I've built the circuit above and connected the 220V input to the mains and put a small light bulb (20W) at the output. The control input of the SSRs are not connected.

    Well, the strange thing is that even without sending control voltages to the SSRs the lamp lights! I'm measuring 110V at the lamp, 8.4V across the SSR1, 4.2V across the SSR2 and 0V across the SSR3.

    There's some good explanation for this? I need to build a modified SSR?

    Thank you very much,

    Brusque

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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Research and Development               Blumenau  -  SC  -  Brazil
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