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I have been using harbor freight tig welder 66787 http://www.harborfreight.com/welding...der-66787.html.I want to add a pedal which i got from ebay but there are no instructions at allhttp://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IThttp://cgi.ebay.com/ws/eBayISAPI.dll...m=370280641590http://cgi.ebay.com/ws/eBayISAPI.dll...m=370280641590its 7 pin plug which need to be reconnected to welder by color code but there are no colors on the welder power dial...see pichow do i attach this jact to my welder ? please help...thanksLast edited by francocali; 11-25-2010 at 08:58 AM.
Reply:The guts behind that power knob are called a "potentiometer", or a "pot" for short.The middle electrical connection (where it looks like its soldered onto the board) is called the "wiper", and the other two connections are the legs.When you turn the knob all the way in one direction, you will have 0 resistance between the wiper and one of the legs, but max resistance between wiper and other leg. Turning the pot all the way in the other direction will reverse the legs having 0/max resistance to the wiper.Regardless of how you turn the pot, you will always have a fixed resistance vale (same as the max value described above) between the two legs.So, what you need to do is get a multimeter, identify where the wiper and legs are on your footpedal, then get out your soldering gun, desolder the pot off the printed circuit board, solder in wiring that hooks up the footpedal plug so the new footpedal wiper and legs are connected where the old pot wiper and legs were. If you did this, your machine will be dependant on the footpedal to operate (you should not turn it on without the footpedal installed.)You will only use 3 out of the 7 connectors in your footpedal wiring this way. The arc also won't necessary stop completely when you lift the pedal fully, it will just taper down to min current.You should make sure the resistance between leg and leg on your footpedal matches (at least pretty close...) the leg to leg resistance of your current weldering machine's pot.There may be better ways to do this, that maintain a functional current control knob on the machine, and allow it to work if the footpedal is not plugged in. This is just one way.
Reply:Dude perfect detail, Jakeru thanks for taking the time to answer my question.Tomorrow i will follow your instruction and see if i can get pedal to work...thanks...
Reply:You're welcome. FYI there should also be 2 pins in the 7 pin connector that will be shorted out when the pedal is pressed down a tiny bit, such as by a microswitch located in the pedal. And you might find there are 2 other pins in the 7 pin connector that are wired together (so you could possibly wire the machine to measure if they are connected, if you wanted to get fancy, to have the machine determine if the pedal is plugged in to the machine.Also, you might be interested in this post:http://www.hobartwelders.com/weldtal...4&postcount=66Too bad the schematic within is missing (I looked but couldn't find it either.) Anyhow this particular footpedal of mine referenced in this post has a knob on the side that adjusts the max current, which is a pretty handy feature. I was thinking you might be interested in wiring your footpedal up like that, so you could control the peak current with the pot on the front of your welder. Sorry I couldn't find the schematic. Its gotta be a pretty simple circuit though... Maybe you can figure out how to wire it based on the resistance measurements in the post. |
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发表于 2021-9-1 00:23:35