|
|
Does anyone know, off hand, what voltage the gas solenoids in MIG boxes use? I assume they are using 12vdc and are "closed" until current is applied. The reason I ask, is that I have a couple inverters that I run DC TIG with, but none have solenoids. I'm thinking of fabricating a simple foot-switch and solenoid set-up to purge and post flow, without diddling with the gas valve on the torch body. My preliminary ideas look like it may cost under $50 (solenoid, power supply, gas fittings, switch, misc wire connectors) in parts to fab it up.Thanks in advance,cricman
Reply:Maybe get a solenoid valve that uses 120VAC.Or use an AC/DC 'wall wart' to power a low-volt DC solenoid through the footswitch.Do other than that, and you are going to have to figure out where to get a power source from inside the welder enclosure. And determine that it can supply the current, and that is protected from inductive flyback when the solenoid is de-energized. - Jim
Reply:I'm definately leaning toward the 12vdc solenoid solution. They're cheap and easy to work with and I can use any of several kinds of 12v power supplies, since most of 12v solenoids draw less than 3 amps. I am definately going to make this a device that is isolated from the welder power, so I can use it on either of the inverter boxes that I have.cricman
Reply:Originally Posted by MotoFabMaybe get a solenoid valve that uses 120VAC.Or use an AC/DC 'wall wart' to power a low-volt DC solenoid through the footswitch.Do other than that, and you are going to have to figure out where to get a power source from inside the welder enclosure. And determine that it can supply the current, and that is protected from inductive flyback when the solenoid is de-energized. - Jim
Reply:One advantage to using an AC solenoid is you can hook it up using a power-off relay timer to control the post flow. If you go with DC, you can build an adjustable resistor/capactor based timer to do the same thing. You'll probably have to use a MOSFET to drive the solenoid.There are no small projects
Reply:At one time Keyence had a micro PLC that could be easily programmed to do the sorts of things you have in mind. It was a 24VDC device. Industrially most solenoids are either 24 VDC or 120VAC, 12 VDC and 5 VDC follow up from there. You should elminate 120 Volt devices right way due to safety.If you go the 24 VDC route you should be able to find a relay or a time delay module that will give you an off delay. This would be your post flow. Buying such new can be expensive so shop around. Get a Newark (allinone) catalog and look on line.ThanksDave
Reply:Thanks guys,I'm definitely going to make this a simple project. Press and hold a momentary contact foot switch to purge and start, scratch start the arc (they are basic dc inverter boxes that I'll use for mild steel), weld, stop the arc and hold for post flow, and released the foot switch to stop the post flow. There are some slow open/close solenoids, but I don't even need to be that fancy. Since most of the welds will be multiple, small (in length), and interrupted, I don't wan't to jack around with turning on and off, the flow adjustment on the torch. I was also thinking of experimenting on a conversion for my Asian flux-core wire feeder (Of course, I'll have to make the polarity of the leads changeable, but thats about a $3 fix, and then run a gas supply to enter the wire liner or, at the very least, the nozzle). Just some non-destructive hacks until I decide which MIG welder to buy, If I buy one at all.Thanks again,cricman |
|
发表于 2021-9-1 00:16:27