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Thread: SSR Question

  1. #1
    Join Date
    May 2007
    Thomasville, GA

    SSR Question

    I changed my CNC from the spindle that came with it to a DeWalt DWP611 router to have a beefier device. So far, so good. I wanted to be able to switch it with gcode commands like I did with the DC spindle, so I built a control box with an SSR-25 DA solid state relay. I use 12VDC from my CNC electronics box as the control signal for the SSR, switching it with an isolation relay in the CNC box. It works just fine - mostly. Actually, the process works great but I doubt I would have noticed an issue if the DWP611 didn't have LEDs on it. The router switches off as commanded but the LEDs remain illuminated at a low level. Making some voltage measurements, I see about 30VAC at the output of the relay when it is "OFF". The input control voltage measures 0VDC. I know SSRs have some leakage. Apparently, the internal resistance of the output side of the relay is such that some voltage is passed but at a very low current. Is there a simple way to defeat the leakage?

    Edit: The switch box I built is for the purpose of turning on the router and shop vac when the CNC cut starts.
    Last edited by Bill Arnold; 11-19-2015 at 08:33 PM.
    Bill Arnold
    Citizen of Texas residing in Georgia.
    NRA Life Member
    Member of Mensa
    Live every day like it's your last, but don't forget to stop and smell the roses.

  2. #2
    Join Date
    May 2007
    Kansas City, Missouri
    I have mine setup with a light switch to kill the 110v to it, usually also switch off the router when not in use. I think you can add a zener(?) diode to drain off any voltage, but don't recall the schematic for it.

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault


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