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Ricardo 03-31-2018 03:34 AM

Tig pedal potentiometer
 
Hi everyone want to ask if anyone can help me so I have a basic tig pedal on my machine and when you connect it the current gets controlled only by the pedal and the knob does not work in conjunction with the pedal so I see on some other machines the pedal has a knob on it so you set it to a point and then when you max out the pedal it can only go so much because of the knobs position on the pedal . So my question is does anyone know how to wire a knob into the pedal itself if you get what I'm trying to say . Thanks

bobadame 03-31-2018 09:06 AM

I have a sewing machine motor that works that way. It is 2 variable resistors in series. One is a rotary potentiometer, the other is a 6 position variable resistor switch.

Ricardo 03-31-2018 09:22 AM

Well I think I only need to put a potentiometer but there is three wires on the pedal yellow brown and blue

bobadame 03-31-2018 10:35 AM

In my example the 6 position switch could be replaced by a second potentiometer. The 3 wires on your pot are ground, input and output. To wire 2 pots in series; with the pot shafts facing up the first terminal is ground, the second terminal is input and the last is output. On your pot the brown wire is probably connected to ground. Verify this with an ohm meter. There should be continuity between this wire and the case of the pot.

So to add another pot in series you would wire the third terminal on the first pot to the middle terminal of the second pot. The third terminal on the second pot is the final output.

The first terminal on both pots should be connected to ground.

Ricardo 03-31-2018 11:58 AM

2 Attachment(s)
As you can see this is my pedal box it's very basic and that's the pot works with the machine which just controls the current so I'll have to just get a rotary potentiometer and connect it the way you just have said

Attachment 46360

Attachment 46361

Ricardo 03-31-2018 12:03 PM

What I was also planning is to not put the potentiometer on the pedal box but make it external in a different box with wires going to the pedal box with those male and female plugs I think it would be easier to adjust when welding instead of bending down to get it and adjust it

John Buchtenkirch 03-31-2018 04:50 PM

Actually in my opinion it should be mounted in the welder so it would work with the foot pedal as well as with a tig torch mounted hand controller. Not my idea at all……… that’s just the way my Miller Syncrowave came from the factory. I use that feature all the time so I don’t blow holes thru the panel when I’m tig fusion tacking 2 panels together :). I've wondered if a wood wedge you slipped under the foot pedal could work as a adjustable stop for welders that don't have this feature ? ~ John Buchtenkirch<O:p</O:p

Ricardo 04-04-2018 02:20 PM

I hear what you saying but my machine doesn't work like that . I also see on you tube when Jody does his videos how he sets the knob to a certain current and the pedal still works like normal but maxes out where his set the knob .which is fine and convenient that some machines come with that but we don't have that in most machines in south africa or alteast I have not seen any with it so this is why I am asking about this . You know in America the have a.c balance in our country most machines say clean area width now as I understand it it's the same thing but makes things confusing when we watch American videos and you have fancy terms for things then we scratch our heads wondering what that is :D

skintkarter 04-05-2018 02:14 AM

Hi Ricardo

It seems we have similarly functioning welders... I've been welding for years but new to tig welding and here in New Zealand a decent Miller or Lincoln is North of $10,000. As my metal gluing is just a hobby, I settled on a well recommended high end Chinese machine for around $2600. It's a 3 phase 315A AC/DC pulse machine and came with a foot pedal. Perfect I thought... But like you I discovered that when you plug in the pedal, it completely disables the amperage controls on the front panel - hence you have the full 315A under your foot when trying to say fuse two bits of 1.0mm CRS. Not good.

The foot pedal has a rotary potentiometer of I think 10 ohms (10k ohms?) which is moved by a toothed belt linked to the pedal. The 'sort of' solution was to introduce a second potentiometer into the pedal casing enabling a 'range' to be set. The problem is that the resulting control turns out to be non-linear with my 5 ohm (5k ohm?) second pot. It has helped, but is not perfect.

Perhaps some electrical gurus can chime in here and sort us both out.

Ricardo 04-05-2018 02:18 AM

Hi yes so basically we on the same boat and yes on the pedal it's a line pot and yes it has the full power of the machine at any given time so adding a seperate rotary potentiometer would be nice problem is wiring it up :o


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