Auto fan shutoff sensor?

Just curious if anyone has made a circuit to shut the fan off when the unit is just sitting idle. I'm thinking about make one with a microprocessor that would monitor the temperature of the internals of the welder and then from basic computations with ambient air shutoff the fan and cooler so I don't have to listen to it and so it's not wasting power. with just the welder switched on with no load and the cooler on I'm pulling 1.6 amps. It may not sound like a lot but over time that idle power draw adds up. I figure I can use a hall effect sensor to sense when the power kicks on to start the fan and then keep it on until the desired temp is reached. So just curious if anyone else has attempted this yet.

This sounds like a good idea, but way above my pay grade. Keep us posted as this idea develops, ok?

absolutely. However this will just be a side project and isn't at the top of the list right now. First off I need to get a good dryer system worked out for the compressor to save my consumables. But as far as building something like this is all fairly easy and can be done for under $50 with the microprocessor and all. Then just some programming in BASIC or C++ and it'll be good to go

I would buy one if you make them.

In the mean time I'll look on ebay, they should ahve ready made ones for many applications. I bet they are $20 or under, but the 220 would have to be resolved OR buy the european model controller....

If you really wanted to do it, you could just use a temperature switch as a trigger and a relay on the fan wire...just need to find a temperature switch for air or whatever it is that you are going to monitor.

They probably do have them on ebay, however if it just uses a temp probe then it will only kick on the fan once the heat sink gets hot. By that time everything else will be cooking since it will take the heat a little while to propogate to the heat sinks. In my case I want it to kick on as soon as it detects current and it would also have the ability to monitor the water temp in the cooler and if that is still a bit too high, it can kick off the fan on the welder and keep the cooler running...or vice versa. Just a bit more able to be tailored to prolong the life of the welder and save on the power bill

Guys,
This is "fan on demand"...which leads to LOWER duty cycle machines. If you want that, go with big blue. lol

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Originally Posted by performance

Guys,
This is "fan on demand"...which leads to LOWER duty cycle machines. If you want that, go with big blue. lol

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right..miller has fan on demand, but again that all comes back around to what I said in my last post about using just a temperature probe. But the unit I am talking about building would be a smart system that would detect the initial current and start the fan then and it could then keep the fan on until a desired pre programmed temperature is reach...perhaps 10 degress above ambient then it would go back into standby mode waiting for you to strike up again. If I'm working on fitting something up for 30 min then there is no sense in letting the fan run for 30 min while it's doing no good. Sure I could walk over and turn it off, then back on but usually by that time I have things in place just where I want then and need to put some tacks up, only to realize I forgot to turn the machine and the cooler back on.

So done correctly, nothing suffers. Duty cycle remains the same. I'm not saying there's anything wrong with your machines, I absolutely love my 256, just looking to cut down on some power use and unneccessary noise

The wattage draw on the fan it self is peanuts, the main juice is the watercooler, when you shut the water cooler off the 1.6 amp draw will reduce dramatically.

one other thing, you don't need microproccesors and all that high tech stuff to control a fan, a simple bimetal strip will move back and forth just like your house hold thermostat and open and close the switch. there are simple thermal switches that start and stop your furnace motor, that kinda stuff. placing them in the right location so they do the job is another challange for the would be DIY guy.

Bottom line: nice idea, but not worth the hassle, would not want my machine to go into over heat and burn up because I was trying to save a few pennies.

I can see the benefit to cutting down the noise. Also, whenever the fan is running, it is pulling air through the machine and over the electronics, which could be dust-laden. If you only had the fan run when necessary, it would cut down on the amount of potentially damaging dust getting inside the machine.

One thing I was surpruised about when I test-drove Angular's IGBT 250EX, was how loud the fan was, and how comparatively little airflow seemed to be coming out of the vents compared to my older Everlast Mosfet-based Super200P. I don't know enough about the design details but there must be a reason why the newer models are louder and don't move as much airflow. I realize cooling the machine is not about just moving air, its about transferring heat and possibly the design of the 250EX accomplishes that. However the noise I would get annoyed by. Too loud to have a reasonably calm conversation with someone right next to the machine really.

Just my 2c coming, from someone who has tried both the older and newer machines. It was one of my criticisms of the newer machine, as I remember. I am curious if the fan blade is significantly different in design comparing new vs old machines.

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Originally Posted by geezer

The wattage draw on the fan it self is peanuts, the main juice is the watercooler, when you shut the water cooler off the 1.6 amp draw will reduce dramatically.

one other thing, you don't need microproccesors and all that high tech stuff to control a fan, a simple bimetal strip will move back and forth just like your house hold thermostat and open and close the switch. there are simple thermal switches that start and stop your furnace motor, that kinda stuff. placing them in the right location so they do the job is another challange for the would be DIY guy.

Bottom line: nice idea, but not worth the hassle, would not want my machine to go into over heat and burn up because I was trying to save a few pennies.

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the fan on the 256 pulls .6 amps and the cooler was a little over 1 amp. You're still not getting what I'm saying as a bi metal strip takes too long to react to a change in temp and by that time the components have already heated up and you're behind the power curve. Hence the hall effect sensor. If/when I get around to building it, I'll post up pics

Timberwolf, don't expect your warranty to hold up if your unit does not. It is NOT a recommended idea. The duty cycle is rated on 10 minutes. The thing is, if you exceed the duty cycle, the unit should cool for 15 minutes before restarting. We are not alone in this, even "on demand" units recommend this time span to deal with residual heat. Pushing close to the duty cycle theoretically should only need 4 minutes, but depending upon a lot of variables, that time could be longer. Just because the heat is lowered in the cooling sinks, doesn't mean the heat is gone in the power circuits yet.

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Originally Posted by Timberwolf

the fan on the 256 pulls .6 amps and the cooler was a little over 1 amp. You're still not getting what I'm saying as a bi metal strip takes too long to react to a change in temp and by that time the components have already heated up and you're behind the power curve. Hence the hall effect sensor. If/when I get around to building it, I'll post up pics

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O.6 amps is like turning off a 150 watt light bulb, to save electricity at the risk of overheating your machine in the process, I am familiar with Hall effect devices, owned a dodge since they invented electronic ignition. However when you get it built I would interested in seeing it. I'm not against new ideas, had some myself, not all turned out the way I expexted them to, but a guy has to keep on trying, that's how inventions are made.

Well perhaps I'll wait until the warranty is out then I reckon. No sense in pushing it. I've been more than pleased with the machine...I don't regret getting it over another Lincoln precision TIG 375 that we had back at the farm. Guess I'll just keep plugging away at the air compressor intercooler for the plasma since this humidity blows in florida.

Geezer, didn't mean to sound brash....I know what you're talking about, some college buddies and myself started a company a little while back that deals quite a bit with inventions. Just got started at the beginning of the year and already have one product out and a few more in the works and on the way.
http://www.ideadevgroup.com/index.html

No problem, Timberwolf good to talk about these things, you did get me to thinking which is good exercise at my age (the old brain doesn't fire on all 8 cylinder like she use to). So here goes FAN ON DEMAND and how much can you really save.

Assuming you work 10 hours aday with your machine and it has 50% duty cycle and electricity costs 15 cents a kilowatt and your fan draws 0.6 amps which is equal to say 150 watts.

That would be 150 X 10hours/1000 X .5 duty x 15 cents.......or 11 and 1/4 cents perday times 365 = 41 dollars and 6 cents per year

So much for the FAN ON DEMAND touted by some people

Wanna save money around the shop build a can/bottle container to recycle them.

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Originally Posted by Timberwolf

absolutely. However this will just be a side project and isn't at the top of the list right now. First off I need to get a good dryer system worked out for the compressor to save my consumables. But as far as building something like this is all fairly easy and can be done for under $50 with the microprocessor and all. Then just some programming in BASIC or C++ and it'll be good to go

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Speaking as Mike, not Mike at Everlast.

If you have a programmer and a free compiler (RVK-BASIC for Atmel, and GreatCOW for Microchip or MikroE) it is an almost free project outside of labor. samples.microchip.com for a 12F675 or 16F88. The programmer you can buy a kit, you do not need a ICD2 type. A thermistor and cap (radioshack or Mouser), pulse it and sample the cap drain with ACD, derive the temp, open/close a relay. This is a crude way to do it, but will work.

I did an LDR (light not heat) circuit years ago. I can see if I have the schematic and board layout and code still. Eaglecad (student version free) and probably MikroE BASIC (free version). You have a thermistor in the range of the LDR I used, a small software tweak, done. If I dig around I am sure I have a PIC you can have as well. Somewhere I have a bunch tubes 12F and 16F, and AVRs too.

BUT, if you mod the machine, you will have a warranty problem. So do this at your own rick.

Also, when the machine goes idle after welding, it needs the fan on to cool the heatsink down for a bit. Are you looking to kill the fan, not when idle, but when the heatsink is cool?

Hang on. I figured the reason for this project was fan noise. There will be NO major power savings unless unit is on 24 hours a day. But the temp sensor will cut it off if cool.

If for power savings, like Geezer said, get a recycle bin. A Kw/H is dirt cheap, the fan draw can not be much.

I figured it was noise, because I will use my IMIG200 over the IMIG250 generally because of the noise. You can whisper with the 200 and yell with the 250P. I love my 250P, but that fan is like the ones in our larger TIGs.

Hey Mike, yes I was looking to kill the fan for the noise primarily and the power draw secondly. The idea behind using a microcontroller was that it can be programmed to monitor the water temp, heat sink temp, and ambient air and know when to turn off the power to the cooler and the welder fan. That way the only thing it's doing is keeping the fans off when not in use. Thats why I was saying it won't effect the duty cycle since the unit will cool down as usual and once cool it would be like just flipping the switch on the back, only instead of doing that the front screen will still be on and it would just be in standby mode. If it did get hot just sitting idle for some odd reason, the fan could again kick back on.

But like I said I'll just put this on the back burner for now and get busy on the air compressor intercooler. Seems as though moisture down here really eats up my consumables, even with a few filters in line.

Oh yea on the consumables and moisture in the tank. I have the throw away desiccant ones stacked behind the cutter.

I will have to get the specs on the fan. Maybe a resistor and a switch even on the front to drop the speed and noise but still running. No uC required that way.

Your project would not be hard, 3 ADC pins over 1. cut and paste code and change pin names. If you re-visit it, I have a one channel version done and code that just needs to be change a hair.

Sounds like you're opening up a can of worms just to save 1.6 amps.

If it aint broken, don't fix it!

In my chosen profession as complex as it may be, an old axiom always manages to hold true. K.I.S.S.

As long as you have good coolant flow and good heat transfer for the coolant and machine. It will work fine all day long. I just did a bunch of welding with my 250EX at more than 225 amps, with nary a rise in coolant temperature.

I could never understand why people make things more complex than they are.

Have a great weekend!

Don