Electric height adjustable Table Convert rocker switch

Discussion in 'The Projects Forum' started by Crashland, Jun 20, 2011.

  1. Crashland

    Thread Starter New Member

    Jun 20, 2011
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    hello ,
    I am battling a common un-met need to open a door at first light and close it at darkness.
    OR simple timed open and close.
    I have two very sturdy and very long life Electric adjustable height tables. They have all needed to go up and down, I removed the table top and and I attached a plate attached to a door on cabinet draw pulls. The 110v unit has a three position rocker switch to make table go up(left) and go down( right) and neutral in middle.
    My question is can I modify the switch to use a light sensative timer or a digital timer to move the table up and down , thus moving the door up and down?
    First using the existing 110v plug and will leave it connected , moving towards solar powering or battery powering the unit by winter.
    Thank you
     
  2. CDRIVE

    Senior Member

    Jul 1, 2008
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    Do humans traverse though the doorway? Please describe the door and the HP of the motor.
     
  3. Crashland

    Thread Starter New Member

    Jun 20, 2011
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    Door will be small for chicken size opening. The table is rated for lifting heavy loads,150 lbs. much heavy than any door I will make and will be using for the "down" holding ability as a currently used automatic coop door had string and racoon pushed door UP.
    The rocker switch moves the pedestal up and down smoothly.
    I was hoping to use that wiring to somehow automate. open at X time and close at X time, or open at sunrise and close at sunset...
    By attaching a sliding door with drawer glides in the vertical postion I can attach to the lift pedestal and close slow to not trap a bird in the door. Not sure on HP on small electric motor about the size of a fist inside tables pedestal. Will look closer for markings.
     
  4. CDRIVE

    Senior Member

    Jul 1, 2008
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    snip:
    Most probably a worm drive gearbox. Please decide whether you want this to function via light sensing, which can be iffy, or timed, which is consistent.
     
  5. CDRIVE

    Senior Member

    Jul 1, 2008
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    snip:
    Abandon this thought. The cost of converting solar, to charge batteries, that power an inverter, to power your motor, will take many years to recoup. The brief periods, each day, that the motor runs is negligible in scheme of things.
     
  6. CDRIVE

    Senior Member

    Jul 1, 2008
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    Hardware stores and home centers sell low cost (~$30.00) digital timers. They're programmable and plug in like a wallwart but with an integral AC receptacle. We can use this timer as the basis for your circuit.

    Since we will have to replace your center off rocker switch with a relay, we will need all the information on your motor plate. We will also need some photos of the wired side of your rocker switch.

    Your motor is most likely a universal type motor. This type of motor can be reversed my swapping the phase polarity of either the armature or the field windings.
     
  7. Crashland

    Thread Starter New Member

    Jun 20, 2011
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    OK so here is a link to some more pictures.
    http://www.itpainrelief.com/Coopdoor/index.html
    I thought since there were 4 wires I could hook up two digital timers, one for up and one for down? And use limit switches to stop movement when door opening is closed or open.
    I intend to have the egg shaped enternece holes on either side of pedestal in the outside walls, the pedestal with have a solid piece of door material bolted to it and will come down sealing the holes. Ad enclose the unit so the birds cannot get to it.
    The black box as a 110v to DC with a photo timer inside? Thought it could be used to open at sunrise.
    The two electirc table pedastals are made by same company, mayline.
    The rocker switch is pictured showing wires best I could.
    I took one of them apart , grey one to show the inside and got some info on the drive systems

    Drive system
    electirc 110v 60Hz AC inout, 12V DC motor. No hydraulics, belts, weights or pullys. Capable of lifting 150 lbs. Motor drives a steel Acme thread, linear actuator with gear reduction. Tested to 25,000 cycles without fail.
    travel time is 13 seconds, 76" per minute.

    so much fun.
     
  8. CDRIVE

    Senior Member

    Jul 1, 2008
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    Wow, that motor @12A (1,440 Watts) is major overkill for a chicken coop door! This will be a big issue with limit switches, which are usually microswitches. It will necessarily increase circuit complexity because the micros will have to control power relays instead of being directly connected to the motor circuit.

    BTW, after re-thinking it... an off the shelf timer isn't going to do the job as I had envisioned it.
     
  9. Crashland

    Thread Starter New Member

    Jun 20, 2011
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    Thank you for your thoughts. Anything else I could try to be able ti use what we have?
    Or is it time to put the $1395 dollar electric tables on Craigslist for $400 and buy the $300 chicken coop door already done..???
    so much fun
     
  10. CDRIVE

    Senior Member

    Jul 1, 2008
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    Do you have a link for the $300.00 chicken coop door? I'd like to see it.

    Here's a link for a company that sells small DC motors. You may want to look through some of them, especially the geared models. Low voltage DC is not an issue and will be easier to work with.

    http://www.mpja.com/products.asp?dept=100

    As an aside, I was hoping for more participation in this thread. We had another Chicken coop door project just a short time back. You may want to search the forum for it to get ideas.
     
  11. Crashland

    Thread Starter New Member

    Jun 20, 2011
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  12. CDRIVE

    Senior Member

    Jul 1, 2008
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    This one is totally complete at a reasonable price. BTW, I see that this seller is using an off the shelf timer, as I had originally suggested. I'm going to rethink this.
     
  13. #12

    Expert

    Nov 30, 2010
    16,261
    6,770
    This thread has served a good purpose. It is the third chicken door thread in 6 months and the answers will be good for several people that will be here in the future.
     
  14. strantor

    AAC Fanatic!

    Oct 3, 2010
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    I think you might be off by a factor of 10. 144W per my math. Seems feasible, but I still wouldn't reccommend it. Those table are too valueable to be anywhere near a chicken coop. I would sell them, then buy a used car door window motor from the junkyard.
     
  15. CDRIVE

    Senior Member

    Jul 1, 2008
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    No, his motor is 120VAC.
     
  16. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Ah, my mistake. Per post #7 it sounded to me like there was a 120VAC > 12VDC converter. Now I see that big 330V cap which looks like the type used with 120V linear actuators.

    Would that 12A rating be measured at stall? I doubt the acutator would be under that much load just opening up a chicken coop door.
     
  17. CDRIVE

    Senior Member

    Jul 1, 2008
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    It's an intermittent duty motor. They are inherently high draw.
     
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  18. Crashland

    Thread Starter New Member

    Jun 20, 2011
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    keep the topics flying I will keep looking up what you are talking about < grin >
    I had decided on the one at http://www.chickendoors.com/ and since monday have been trying to order one. Questons take days to get an answer and now waiting again for some simple questions.
    Will have to try the other ones linked above withouth the repoen feature as I need something by Sat. and others have been responsive to the 10th degree and ship overnight.
    The tables were on our property brand new in boxes when we bought it so was trying to use them and not buy. The ones linked above will be the answer if I can sell the tables on CL.
    or if with your help I figure something else out...
     
  19. CDRIVE

    Senior Member

    Jul 1, 2008
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    It's not that I don't think we can do it here. It's ... Can we do it within your time frame (doubtful) and can we do it cheap enough to make the effort worth while, as compared to ready to go units. Your 12A motor is definitely overkill and not energy efficient.
     
  20. CDRIVE

    Senior Member

    Jul 1, 2008
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    OK, I've given this a bit more thought and I'm back to using an off the shelf digital timer as the heart of this project. This is because only a microcontroller would be practical for the timing functions of this device and few electronics amateurs have the skills to work with them. Even if they did, the display and time set interface would cost as much or more than an off the shelf model.

    It's doubtful that I'll get this done in the time frame that you require because I've got some unrelated work to do in my wood shop. On the other hand, home grown Chickens seems to be all the rage right now so this circuit and mechanical suggestions will be useful for the next guy needing this.

    I'm sorry that I was unable to do this for you.
     
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