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Photoelectric Switch controlling a 12V DC Motor.

Discussion in 'Sensors and Actuators' started by Donald, Feb 3, 2013.

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  1. Donald

    Donald

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    Feb 2, 2013
    I have a Photoelectric Switch controlling a 12V DC Motor. A 12V battery serves as the only power source. When connected the motor just makes a clicking sound. I tried smaller motors that worked. For some reason they now also just make a clicking sound and do not work.

    Any reccomenddations are greatly appreciated. thank you.

    Don-
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    11,513
    2,651
    Nov 17, 2011
    What's that photoelectric switch? An off the shelf part or a selfmade contraption?
    What's the rating of the switch and the ratings of the motors used?
    Can you measure voltages and currents at the inputs and outputs?
     
  3. duke37

    duke37

    5,364
    771
    Jan 9, 2011
    If the battery voltage collapses when on load, the relay will drop out and the battery voltage will recover, the relay will energise again and so on.

    Make sure the battery is charged and in good condition.
     
  4. Donald

    Donald

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    0
    Feb 2, 2013
    Thanks so much for the quick response. Sorry for the delay. Family and travel issues popped up. And I can only work on this when the wife is asleep at night ;o)

    Here’s what I’m working with:

    Dayton DC Motor
    12 Volt PM DC
    HP. 1/35 RPM: 2350
    FL AMPS: 3.70

    Keyence Photoelectric switch. PR-MF Series
    Power voltage: 10 to 30 VDC, including 10% ripple (P-P)
    Control output: NPN or PNP Open controller, 30 V or less. 50 mA or less

    A multimeter reading from the wires (brown & blue) from the photoelectric switch to the motor indicates 2-3 amps and upwards of 10-12 volts as I’m using a volt regulator to supply power. I’m experiencing the same results when connected to a 12 V battery.

    I’ve tried smaller motors to trouble shoot. They began to work with the photoelectric sensor then all stopped working and emitted the same clicking noise. Feels like back EMF or something mucking up the works. I have tried an ice cube relay (not sure if I connected it properly and will try again). Would inserting a capacitor resolve? Any input is greatly appreciated?
     
  5. john monks

    john monks

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    2
    Mar 9, 2012
    What if you try with a small 12 volt light bulb?
    Maybe there's something Strange going on in your Keyence switch.
     
  6. Donald

    Donald

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    Feb 2, 2013
    I thought the same and purchased another switch. I'm on my third and the issue is consistant
     
  7. john monks

    john monks

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    2
    Mar 9, 2012
    What I meant was that there may be an SCR or other type of transistor circuit incorporated in the switch that might have current limiting. I'm trying to find the specifications on the switch. What happens when you bypass the switch? Do you have a voltmeter? Can you see what the voltage drop across the switch when the motor is making the clicking sound?
     
  8. Donald

    Donald

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    Feb 2, 2013
    I see. Good point. I'll test that out to see confirm. Would the ice cube relay get around that?
     
  9. duke37

    duke37

    5,364
    771
    Jan 9, 2011
    What battery are you using?
    Is it fully charged?
    Have you measured the voltage on load?

    If it worked for a while, then stopped, it appears the battery ran out of breath!

    What is an ice cube relay?
    What is the voltage rating of the coil and its resistance or current consumption at 12V.
     
  10. EinarA

    EinarA

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    0
    Feb 11, 2013
    In post #4 the specs Donald gives list the max control current as 50 mA and the motor draws 2-3 amps. You need a relay or a power transistor to drive the motor.
     
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