Duck house....

Discussion in 'General foundry chat' started by Zapins, Sep 9, 2021.

  1. DavidF

    DavidF Administrator Staff Member Banner Member

    Sounds like something that can be cured with a couple relays that have both nc/no positions
     
  2. I just went through this for my electric hoist up down controls. There are two relays, one for each direction. By using the normally closed contacts, you run power to the opposite relay coil, this means only one relay can be activated at a time as it cuts power to the opposite relay coil. Both relays on at once will short out the power supply as one relay supplies door open power and one supplies door close power (reverse polarity). If a door limit switch is activated it cuts off the corresponding relay coil but doesn't interfere with the other opposite direction relay....so if the door open limit switch is activated, power can still close the door and vice versa.

    door opener.jpg
     
    Last edited: Nov 6, 2021
  3. Zapins

    Zapins Gold

    Last edited: Nov 7, 2021
  4. Sorry for the late reply I've had a flying inspection by my foundry Sensei on my recent efforts. Yes the yellow symbols are common bog stock DPDT relays: double pole, double throw. So you'll need to get a coil voltage similar to your motor power supply, like 12 or 24 Volts. Those relays you linked to are a bit on the small side, DC motors have a fair bit of surge inrush current so relays with 10 Amp contacts will handle any possible contact arcing on operation and last a decent while (similar to your second Amazon link):

    https://www.ebay.com.au/itm/353564582088?hash=item52521760c8:g:92YAAOSwiT9g5Uzd

    They also have a clear case so you can visually see where the contact tags go, if it's operating and also if there's burnt out contact down the track. You can buy sockets for them or just solder wires to the tags and slip a bit of heatshrink over the wire and terminal to insulate it. Also 24 volt relays will usually work fine off 12 volt supply so buy them if they are cheaper to get than 12V units.
     
    Last edited: Nov 7, 2021
  5. Peedee

    Peedee Silver

    If it goes wrong then it's all round yours for crispy duck :) sorry, that wasn't helpful, what they said!
     
    Mark's castings likes this.
  6. rocco

    rocco Silver

    Yes, there are relays specifically, DPDT relays. (DPDT= double pole, double throw)
     
  7. 3Dcasting

    3Dcasting Copper

    You basically want to disconnect (using a switch) the cables that specifically open the door and not the cables that power the motor. Thus the motor always has cables to be commanded (using relays or other circuits to close the door again).
     
  8. mytwhyt

    mytwhyt Silver

    I don't have a very good grip on electracy, other than it runs downhill until gets to the ground.. Sounds like it works like it should to open and turn off the power... Another circuit from a/the timer to the motor with a reversed current should turn it the other way to close at bedtime.. I use an on/off/on switch for my 12volt intake and exhaust fans.. Maybe I just don't understand the problem.. Wouldn't be the first time someone said " you'll have to explant it to him again..
     
    Mark's castings likes this.
  9. Zapins

    Zapins Gold

    I got some of those clear relays. Will see on Wednesday when they arrive.

    Basically the issue I have is the pressure switches I hooked up cut the power to the motor entirely. So when the door opens and hits the pressure switch it cuts the power to the motor and locks the door in the open position. But since the door is locked in position it still is pressing on the pressure switch which still keeps the power to the motor off. So I can't tell the motor to run the other way because the switch keeps the power off. So I'd have to manually pull the door off the pressure switch to restore power to the motor. And I can't do that because the motor is a worm gear and can be manually turned. That's why I need the relay circuit to route power around the lever switch and provide it to the motor when I press a button.
     
  10. Zapins

    Zapins Gold

    The far right wires appear to go to a manual forward/backward switch but how do I know which wire to use for that with what I have?
    20211111_193512.jpg
    20211111_193653.jpg
     
  11. Is that your speed controller?. The switch on your arm with the thicker red and black wires is your motor polarity reversal switch. The switch can be left in, in case the relays are running the motor in the wrong direction initially or it can be removed and replaced with wire links. The two relays would be connected after this board on to it's motor wires, be advised at lower speed settings the voltage may not trigger the relay coils if set to a very low speed.
     
  12. Zapins

    Zapins Gold

    In the wiring diagram it says "door open switch" on the right side. Looks like it has two separate buttons or switches to open and close. My one has a two directions in one switch as seen in picture on my wrist. I will take the switch apart to get a better view of the wiring but I'd like to wire it up if possible without getting multiple buttons or additional switches. Any idea how I could use what I have?
     
  13. Is it a motor speed control board, I have no idea what it is or it's function and I can't tell just by looking at it, only guess. Is there a link to instructions?
     
  14. Zapins

    Zapins Gold

  15. Does the door opener motor run too fast on 12 volts?, how does it run on 6 volts?. What I'm asking is if you need the board at all as at lower speed settings the voltage may not be enough to operate the relays correctly at very low settings.
     
  16. Zapins

    Zapins Gold

    I just run it on 12 v at max speed. I don't use the voltage speed controller. I just thought the board was nice to have and had everything wired in if I needed to alter the speed. Turns out 260 rpm is on the slower end of acceptable so the board isn't really needed.
     
  17. Ahh ok, that's good then, it may be better to start with just the two relay circuit with two 24 hour interval timers, one set to open the door and the other timer to close the door. The reason for not just using timers and limit switches to control the motor directly is the relays lock out each other and prevent both timers trying to drive the motor in opposite directions (power supply short circuit). The other alternative is some kind of dedicated gate opener controller: these sense the limits of travel by the motor drawing excess current at the limits of travel and have no limit switches (requires a beefy set of door hinges and a strong door). At least with relays circuit you get some practical experience of "Relay Logic" which is the ancestor of solid state logic.
     
    mytwhyt likes this.
  18. Zapins

    Zapins Gold

    Just need one timer to open door. Because I can't be sure the ducks will be inside when the door needs to be closed. Will need to manually close door with a switch or button. Opening it into he morning would be fine with a timer though.
     
  19. Hahah, so a set of duck perches with series connected microswitches to close the door once the right number of ducks are nested :D
     
  20. Zapins

    Zapins Gold

    Haha. Sounds like the beginning of a rube Goldberg machine
     

Share This Page