Automatically Move Linear Actuator

Discussion in 'The Projects Forum' started by ravens3333, Mar 15, 2016.

  1. ravens3333

    Thread Starter New Member

    Mar 15, 2016
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    Hey guys! I am sure that there is a very simple solution to my problem but I know very, very little about what I could do to fix this. I am working on a school project and I need to make my linear actuator automatically go in and out, and I am not sure what needs to be connected to it. The end of the actuator has a wire going through it that needs to be moving back and forth, so there is no load whatsoever on it. It just needs to switch directions when it reaches the end full 2" and it will need to run for about 2-3 hours at a time. Below I put the link to the actuator and power supply that were purchased. Thank you for any help that you can provide!

    Actuator
    http://www.amazon.com/Heavy-Linear-Actuator-Stroke-Lift/dp/B00GYFKDCU/ref=cm_cr_pr_bdcrb_top?ie=UTF8

    Power Supply
    http://www.amazon.com/AspenTek-Supply-Adapter-Cabinet-Lighting/dp/B0180ASJF4
     
  2. crutschow

    Expert

    Mar 14, 2008
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    I could not find the current requirements for that actuator so I'm not sure if the 1A power supply you purchased is adequate to operate it. For example this actuator, which looks very similar, requires 4.6A maximum.
    Do you know how much current your actuator takes?
    Have you tried it with that power supply?

    The simplest way to do what you want is to use two limit switches, such as one of these, and a latching relay, such as this.
    The limit switches alternately actuate the relay to its opposite state at each limit and the relay output controls the direction of the current to the motor to reverse its direction.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Although the listing does not mention limit switches, according to questions asked there the answers was it has internal limits (apart from the clutch).
    If the internal limits are SPDT then you could possibly rewire for automatic reversal, this is done by a diode across each limt.
    That P.S. is only 12w may not be enough.
    Max.
     
  4. ravens3333

    Thread Starter New Member

    Mar 15, 2016
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    I am unsure how much current it requires, but I tried it with the power supply and it does work
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    But for how long?;)
    Max.
     
  6. ravens3333

    Thread Starter New Member

    Mar 15, 2016
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    I have no idea. I attached the wires and had it run until the actuator was fully extended. When I realized it would not retract, I switched the wires around and it pulled the actuator in. All of this was done within 5 minutes so I have no idea how long it can work.
     
  7. crutschow

    Expert

    Mar 14, 2008
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    Do you have a meter to measure the current?
    If so, do you know how to do that?
     
  8. ravens3333

    Thread Starter New Member

    Mar 15, 2016
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    I do have one and I can get the measurement for you tomorrow. Unfortunately, I am not allowed to take the project hoke from school.
     
  9. John P

    AAC Fanatic!

    Oct 14, 2008
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    Is it OK if the unit pauses at each end of the travel? If so, you could measure how long it takes to go from end to end, and add a good margin--say 50%--and then just rig up a timer to reverse the power. The actuator would run to the end of its travel, hit the limit, wait until the power reverses, then run back the other way and hit the limit and pause again.

    If you can't tolerate that pause, you could sense current and when it drops to zero, reverse the power.
     
    Last edited: Mar 15, 2016
  10. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The questions and comments make it pretty clear that the actuator has internal limit switches. Since it has only two power wires, it probably has a diode across each normally-closed contact. The internal switches limit what you can do in terms of controlling the motion. A simple 50% duty cycle timer driving a DPDT relay is sounding better. There's gotta be a long range 555 module on ebay somewhere with either 1 DPDT or two SPDT relays.

    ak
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It looks like the lead screw just has a lift off cover (one screw), if so check to see if it has SPDT limit SW's, then all you need is a on off switch and a relay if the limits are wired for automatic reverse.
    Max.
     
  12. ravens3333

    Thread Starter New Member

    Mar 15, 2016
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    It measured 1 amp
     
  13. ravens3333

    Thread Starter New Member

    Mar 15, 2016
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    A pause would be perfectly fine. Would I need to buy two timers (one for each end) or just one timer?
     
  14. crutschow

    Expert

    Mar 14, 2008
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    Does the actuator stop with the current going to zero at the end of the stroke, or does it just stop with the motor still drawing current?
     
  15. MaxHeadRoom

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    From the description, I'm guessing the motor is still powered and if a slipping/torque clutch it is drawing current enough to over power the clutch.;)
    Max.
     
  16. crutschow

    Expert

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    Then why are we talking about a built-in limit switch? :confused:
     
  17. MaxHeadRoom

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    I am assuming it is a fail-safe option, just guessing at this point!
    Max.
     
  18. MaxHeadRoom

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    I searched all through the manuf. web site and could not find any details on construction or spec's apart from thrust force.
    Max.
     
  19. crutschow

    Expert

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    So I think the OP should do the measurement I suggested in post#14 and settle the issue.
     
  20. John P

    AAC Fanatic!

    Oct 14, 2008
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