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U2008B - ac motor speed controller with soft start

Discussion in 'Sensors and Actuators' started by Lautrec, Oct 28, 2017.

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  1. Lautrec

    Lautrec

    3
    0
    Oct 28, 2017
    Hi, everyone.
    I tried to make ac motor speed controller for my angle grinder.
    After bought U2008B chip I created PCB using circuit from datasheet of U2008B, but the controller doesn't work correct.
    The controller doesn't work in "soft-start" mode and it doesn't work in "current-sensing mode" at all.

    After I added capacitor 47µ/25V (I see this version in the WEB; look the pic.) the "soft-start" present, but in second mode the chip doesn't work at all, it behaves as if there is no power supply to the PCB.

    I need some help. Thank you.

    AC-Motor-Speed-Controller-U2008B.png ; 1.jpg ; 2.jpg
     
  2. Bluejets

    Bluejets

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    828
    Oct 5, 2014
    Do you have a link to the original?
     
  3. Lautrec

    Lautrec

    3
    0
    Oct 28, 2017
    You mean link of original circuit, right? I'm a little bit confused.
     
  4. Bluejets

    Bluejets

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    828
    Oct 5, 2014
    Thats the one. As you say you've changed certain things and it would be helpful to see what the original was and what the specs are.
    Also anything else you used.
     
  5. Lautrec

    Lautrec

    3
    0
    Oct 28, 2017
    Whatever. I think this IC is not very good for my project. I'll try another one with U211B or TDA1085C but in this case soft-start not present and the last may be even LM358. I'll see.
     
  6. Minder

    Minder

    2,948
    623
    Apr 24, 2015
    What is the motor technology? that controller is only suitable for a Universal motor, not a induction motor.
    M.
     
  7. Bluejets

    Bluejets

    4,004
    828
    Oct 5, 2014
    Whatever..............
     
  8. 73's de Edd

    73's de Edd

    2,848
    1,209
    Aug 21, 2015
    Sir Lautrec . . . .

    OBSERVATIONS:
    You definitely need to LEAVE the R6 shunt sampling resistor in circuit.
    You need to stop trying the GRINDER and plug in a small electric drill to initially then evaluate that units (probable meager) capabilities.
    ANGLE GRINDERS . . . my units and experiences:
    I have a 5-6 inch wheeled Milwaukee and it JERKS my wrist on start up, so there is quite an initial CURRENT PULL on its start up.
    I also have a Blacks and Diggers 12 inch wheeled commercial, that I have to brace my body or butt before I start it up.( And mutter under my breath ? Are you ready for this ! )
    Now with there INHERENTLY being the HIGH sustained initial currrent pull on start up, I don't see much chance of there ever being a SLOW START up aspect, with the grinder.
    With the drill . . .yes.

    73's de Edd
     
    bushtech likes this.
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