Connect with us

Wiring 2 Potentiometers Together

Discussion in 'General Electronics Discussion' started by Evolvo, Apr 9, 2014.

Thread Status:
Not open for further replies.
Scroll to continue with content
  1. Evolvo

    Evolvo

    5
    0
    Apr 9, 2014
    Hello,

    This is my first post in this forum and I know almost nothing about electronics except for what I've learned in last 3 weeks. I found this forum by searching google for how to wire 2 potentiometers and the post I found was helpful but didn't clear things up all the way.

    Here's the background. I'm using an 11 amp variable speed sander as a stationary polisher inside a box to polish lightweght tools and other materials. The sander is mounted so the buffing pad is facing up inside a box. The Sander has a AC voltage controller with a 20k ohm potentiometer. The knob goes from 1 to 6 with six being the lowest speed. When the unit kicks on it is going at the lowest speed as either there is a trimpot on the controller or the 20k is not enough resistance to stop the motor not sure of which.

    What I'm doing is hooking up my own ac controller I purchased that has a red orange and black wire coming out of it and comes with a trimpot to have a maximum resistance. This unit must be used with a 2w potentiometer. I would use old but its cumbersome.

    So I hooked up the ac controller and a 250k ohm potentiometer to the thing and controlled the polisher and set the trimpot because turning the potentiometer knob from highest resistance to lowest it took halfway before the unit would turn on.

    So thats the setup. What I'd like to be able to do is to set a maxium and and minimum using the ac controller and 2 potentiometers. I think that the 250k pot is way overkill and I should probably use what was on the original controller which is a 20k pot then wire that to maybe a 2k or 5k pot. I haven't test an amp using the pots as I don't know how to, just have a multimeter that measures voltages and ohms not amps. Maybe there is a conversion I'm not aware of or if I need new tool. Anyway I want to be able to adjust from about 1 to 2 speed if we consider the original ac controller but I don't know the reistance or anything just trying to guess. The old 20k pot did one full revolution to go from minium speed to max with 1-6 being evenly spread apart on the wheel.

    So my question is can I wire a 20k to a say 2k or and this work as fine tune control will I still have a wide range of resistance? I tried last night with 2 250k ohm pots and it slightly worked but there was still a wide range where if I was able to get a good low speed then the max speed would be very high.

    Man I know this is alot I hope someone reads it, lol. Sorry for the rant.
     
  2. Arouse1973

    Arouse1973 Adam

    5,177
    1,093
    Dec 18, 2013
    Hello
    Are you able to do a quick sketch of your connections and POT locations including the equipment and label them accordingly. This really help us visualise it better.
    Adam
     
  3. Evolvo

    Evolvo

    5
    0
    Apr 9, 2014
    I don't know how to read or write in schematic form so here's my best.
     

    Attached Files:

  4. Arouse1973

    Arouse1973 Adam

    5,177
    1,093
    Dec 18, 2013
    That a good start now tell us what wire does what. Is this mains potential? You have three wires going into one connection block what are they.
    Adam
     
  5. Evolvo

    Evolvo

    5
    0
    Apr 9, 2014
    Lol, I don't know what the wires are. I thought you could tell by looking at them. I only hooked them up based on a diagram sent with control unit and pics online. I figured the pic would show you what the wires are by showing the flow of electricity. I suppose the 3 wires are 2 grounds and one power from the pots but I don't know how to describe them. You got 2 wires coming in off the wall then after that i just connect them based off research. It all works I just want to understand the relationship between ohms more and whether there is a way to wire for minimum and maxium volts. I know you can do this with 3 pots but I am trying to do it with 2 and hoping I can use the perferct reistance with one pot to control low speed and make it not go below a certain speed. So just wondering if this kinda all looks ok.

    I posted the 3 pot precision setup below

    http://www.allaboutcircuits.com/vol_6/chpt_3/8.html
     

    Attached Files:

  6. Arouse1973

    Arouse1973 Adam

    5,177
    1,093
    Dec 18, 2013
    If you are not worried about controlling the high speed and are just concerned about the slowest low speed then you could use a fixed value resistor and have a pot across it. Then as you reduced the speed by turning the pot the speed will only be as slow as the value of the two resistors in parallel. 1/RT=1/Rpotmax+1/Rseries is the value of the total resistance. If you wanted to cap the top end the you would put a series resistor on the pot and then put all this across the low speed resistor.
    Adam
     
  7. Evolvo

    Evolvo

    5
    0
    Apr 9, 2014
    I'm not educated enough to know what your talking about there or how to wire, it sounds awesome though. I'm just wondering can my method work or not mostly. I only understand pots and a bit about ohms and resistance. I could use your method but I don't know what value resistor to use or how to wire without a picture diagram. Sounds like you know what your talking about though. If you don't mind showing me a pic of how this would work or what possible values to use I'd be game to give it a try.

    I take it that a resistor is a stationary non moveable pot, is that a good way to think about it. I'm able to input a certain value in the line and it would stay at that value. I think this is what you mean.

    I'd also love to read a begginners guide to electronics if someone has a suggestion for a newb like myself.

    Thanks.
     
  8. davenn

    davenn Moderator

    13,993
    2,019
    Sep 5, 2009
    I suggest you don't go any further with this yourself
    find some one qualified local to you that can look at it and see if he can do anything after you describe to him what the problem is

    working with mains powered equip isn't for the unskilled
    we don't want to see your name in the obituary column

    cheers
    Dave
     
  9. Evolvo

    Evolvo

    5
    0
    Apr 9, 2014
    Unacceptable for me, Either I'm bad at explaining what I'm trying to do or your not the correct person anwering my question. Here is a link to someone in this forum asking the exact same question as me and the people who replied had excellent info on pots how to wire and how to make them work to fine tune speed, except I'm just looking to have a max speed setting on the motor. If what I'm trying to do with the 2 pots is impossible then just say so and I'll take the next step in learning resistors, obviously its possible with 3 pots so what I'm saying isn't out of nowhere. I'm simply wondering can I subsitute using an extra pot for using a certain value pot that would do the job of 2. Arouse thanks for your assistance your doing a good job. I've gotten this far in a week by myself and I'm close, I'm not giving up. I rather get shocked a few more times, trial and error. I'll learn or get burned, LOL

    https://www.electronicspoint.com/threads/series-potentiometers.239658/
     
  10. peter.rabbit

    peter.rabbit

    11
    0
    Mar 16, 2014
    Mains voltage.... 'trial and error'.... 'LOL'....
    You might only get to make that error once matey.... good luck....
    Make sure your RCD is working.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Thread Status:
Not open for further replies.
Electronics Point Logo
Continue to site
Quote of the day

-