Forums

DC potentiometer

Started by Joe Schmucker March 4, 2012
Easy question from a really dumb noob.

I have a 9volt DC motor that draws 500 ma current.  Is there a simple
potentiometer I can put on this motor to control the speed?  It is on
a wire fed welder that is either ON or OFF.  I want to control the
speed of the feed motor.

Appreciate any advice.  If you slam me for being a dorkus, I will take
it.  I'm not too thin skinned.  :-)

Joe
On Sun, 4 Mar 2012 16:48:51 -0800 (PST), Joe Schmucker
<wingloader@gmail.com> wrote:

>Easy question from a really dumb noob. > >I have a 9volt DC motor that draws 500 ma current. Is there a simple >potentiometer I can put on this motor to control the speed? It is on >a wire fed welder that is either ON or OFF. I want to control the >speed of the feed motor. > >Appreciate any advice. If you slam me for being a dorkus, I will take >it. I'm not too thin skinned. :-) > >Joe
If you just use a potentiometer the torque will drop fast and the speed regulation will be poor. You can buy kits that will control the speed with PWM which will retain the torque and fairly good speed regulation at lower than full speed. See the links: http://www.canakit.com/5a-motor-speed-controller-pwm.html http://www.electronickits.com/kit/complete/motor/ck1400.htm This one is already assembled: http://store.qkits.com/moreinfo.cfm/MXa066 The one at the bottom of this page is only ten bucks: http://www.quickar.com/tkit.php Since the welding wire experiences the same friction (pretty much) over the speeds you will be using the motor needs to be able to produce the same torque at lower speeds. If the speed regulation of the wire is poor then you will have all sorts of trouble welding. Eric
"Joe Schmucker"
> > I have a 9volt DC motor that draws 500 ma current. Is there a simple > potentiometer I can put on this motor to control the speed? It is on > a wire fed welder that is either ON or OFF. I want to control the > speed of the feed motor.
** A * wire wound * pot of about 25 ohms and 5 watts rating should do the trick. Just wire one end to the DC supply and the wiper to the motor. .... Phil
On Sun, 4 Mar 2012 16:48:51 -0800 (PST), Joe Schmucker
<wingloader@gmail.com> wrote:

>Easy question from a really dumb noob. > >I have a 9volt DC motor that draws 500 ma current. Is there a simple >potentiometer I can put on this motor to control the speed? It is on >a wire fed welder that is either ON or OFF. I want to control the >speed of the feed motor. > >Appreciate any advice. If you slam me for being a dorkus, I will take >it. I'm not too thin skinned. :-) > >Joe
You already received answers but just a comment. I don't think I have seen a wire fed welder where the wire feed rate was not controllable. What brand and model is your welder? Tom
"Joe Schmucker" <wingloader@gmail.com> wrote in message 
news:60b3de1f-bb0b-4091-9f6e-afdb3a7b8c6a@eb6g2000vbb.googlegroups.com...
> Easy question from a really dumb noob. > > I have a 9volt DC motor that draws 500 ma current. Is there a simple > potentiometer I can put on this motor to control the speed? It is on > a wire fed welder that is either ON or OFF. I want to control the > speed of the feed motor. > > Appreciate any advice. If you slam me for being a dorkus, I will take > it. I'm not too thin skinned. :-) > > Joe
You want something like this http://www.ebay.com/itm/PWM-DC-Converter-9V-28V-Micro-DC-Motor-Speed-Controller-Adjuster-DC-Motor-Driver-/320860004870?pt=LH_DefaultDomain_0&hash=item4ab4bf2206 Or, go to your local electrical equipment supply, they might have something similar Or ask them if they know someone who could assemble one of these circuits for you http://www.discovercircuits.com/DJ-Circuits/simplepwm2.htm http://pcbheaven.com/circuitpages/PWM_Fan_controller_using_a_555/ http://www.solorb.com/elect/pwm/pwm2/index.html
On 2012-03-05, Joe Schmucker <wingloader@gmail.com> wrote:
> Easy question from a really dumb noob. > > I have a 9volt DC motor that draws 500 ma current.
4.5W
> Is there a simple potentiometer I can put on this > motor to control the speed?
to control the speed of simple DC motors you need to control the voltage they get,
> It is on a wire fed welder that is either ON or OFF. I want > to control the speed of the feed motor.
you can probably buy a feed speed controller from the welding supply place, but its probably cheeper to build one. if you put a resistor (which is basically what a rheostat is) in series with the motor it will mainly reduce the torque, the result will be more feed jams. you need to use some sort of voltage control, pussible with a surge on start up to overcome static friction. -- &#9858;&#9859; 100% natural
On 3/4/2012 7:22 PM, etpm@whidbey.com wrote:
> On Sun, 4 Mar 2012 16:48:51 -0800 (PST), Joe Schmucker > <wingloader@gmail.com> wrote: > >> Easy question from a really dumb noob. >> >> I have a 9volt DC motor that draws 500 ma current. Is there a simple >> potentiometer I can put on this motor to control the speed? It is on >> a wire fed welder that is either ON or OFF. I want to control the >> speed of the feed motor. >> >> Appreciate any advice. If you slam me for being a dorkus, I will take >> it. I'm not too thin skinned. :-) >> >> Joe > If you just use a potentiometer the torque will drop fast and the > speed regulation will be poor. You can buy kits that will control the > speed with PWM which will retain the torque and fairly good speed > regulation at lower than full speed. See the links: > http://www.canakit.com/5a-motor-speed-controller-pwm.html > http://www.electronickits.com/kit/complete/motor/ck1400.htm > This one is already assembled: > http://store.qkits.com/moreinfo.cfm/MXa066 > The one at the bottom of this page is only ten bucks:
> http://www.quickar.com/tkit.php
The quickar webpage is terrible to look at and even worse to read. Good example of how note to design a webpage. Mikek
On Sun, 04 Mar 2012 23:22:52 -0500, Tom Biasi <tombiasi@optonline.net>
wrote:

>On Sun, 4 Mar 2012 16:48:51 -0800 (PST), Joe Schmucker ><wingloader@gmail.com> wrote: > >>Easy question from a really dumb noob. >> >>I have a 9volt DC motor that draws 500 ma current. Is there a simple >>potentiometer I can put on this motor to control the speed? It is on >>a wire fed welder that is either ON or OFF. I want to control the >>speed of the feed motor. >> >>Appreciate any advice. If you slam me for being a dorkus, I will take >>it. I'm not too thin skinned. :-) >> >>Joe >You already received answers but just a comment. I don't think I have >seen a wire fed welder where the wire feed rate was not controllable. >What brand and model is your welder? >Tom
A friend of mine bought a cheap welder at a garage sale that has only 3 settings for the voltage and no settings for the wire speed. I assume the welder adjustst the wire speed according to voltage setting. No matter how it works the welder is a piece of junk and it is hard to get good welds with it. Instead of adjusting the welder to the material you have to change material thickness to suit the welder. Eric
On Mon, 05 Mar 2012 08:06:42 -0800, etpm@whidbey.com wrote:

>On Sun, 04 Mar 2012 23:22:52 -0500, Tom Biasi <tombiasi@optonline.net> >wrote: > >>On Sun, 4 Mar 2012 16:48:51 -0800 (PST), Joe Schmucker >><wingloader@gmail.com> wrote: >> >>>Easy question from a really dumb noob. >>> >>>I have a 9volt DC motor that draws 500 ma current. Is there a simple >>>potentiometer I can put on this motor to control the speed? It is on >>>a wire fed welder that is either ON or OFF. I want to control the >>>speed of the feed motor. >>> >>>Appreciate any advice. If you slam me for being a dorkus, I will take >>>it. I'm not too thin skinned. :-) >>> >>>Joe >>You already received answers but just a comment. I don't think I have >>seen a wire fed welder where the wire feed rate was not controllable. >>What brand and model is your welder? >>Tom >A friend of mine bought a cheap welder at a garage sale that has only >3 settings for the voltage and no settings for the wire speed. I >assume the welder adjustst the wire speed according to voltage >setting. No matter how it works the welder is a piece of junk and it >is hard to get good welds with it. Instead of adjusting the welder to >the material you have to change material thickness to suit the welder. >Eric
OK, doesn't sound like it's worth messing with. If you can get some fun out of it by all means play with it. Tom
Joe Schmucker wrote:

> Easy question from a really dumb noob. > > I have a 9volt DC motor that draws 500 ma current. Is there a simple > potentiometer I can put on this motor to control the speed? It is on > a wire fed welder that is either ON or OFF. I want to control the > speed of the feed motor. > > Appreciate any advice. If you slam me for being a dorkus, I will take > it. I'm not too thin skinned. :-) > > Joe
Welder DC Power for Motor (+) polarity. -o _/o-------+----------------+ / | | | | | | + 100 + .-. ___ |/ | |<-- -|___|- -| NPN power Transistor 10K POT | | |> '-' | + +---+---------+ | .--+---. | | | | | | | Motor| | | | | z 12V zener | | | A + '---+--' | GND | | +--------+ === GND (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) heat sink mount the transistor and pay attention because the tab is connected to the center leg on most. That is, when using a TO-220 type package part. These things can be gotten from radio shaft if you want to pay the price. Jamie