Sip 150 wire issues fixed

First i'd like to thank the guys that have been working on the SIP wire feed issues, you were a great help.

Today after reading some posts on sticky wire feed i decided to have a go at sorting mine out, I've had the welder for about 12 years and its never really welded how i want.

So with the help of the info on this site, i fixed my wire feed issue with a bit of ali plate to brace the wire feed bearing and some curtain wire for a new torch liner.

The SIP now welds better than when i bought it, and all for the grand total of .... dig this ... 99p and a trip to dunelm

Thanks again guys.

oh god, how wrong was I! tried to weld some sills on today and it was bloody atrocious, spitting and splattering everwhere, you could hear the motor stepping up and done like crazy.

Odd thing is though, it only seems to happen at lower power settings. i can get really nice beads on most stuff as long as the gun is pointing down, soon as you invert it then its all over and you get pigeon pooh pooh for weld!

I've order this ...

http://cgi.ebay.co.uk/24V-3A-DC-Uni...ctronics_PowerAdaptors_SM?hash=item3ca0cb7347

As its a switching supply I'm hoping that I wont need a relay to switch the motor on. see how it goes when it turns up.!

got to a point today where i wanted just to burn the bloody thing and just go and buy a new snapon! Hoping now that this mod will transform this utterly useless welder.

M.

I found the same before I modified mine. It seems a lot worse when you start pointing the torch upwards under a car.

themininut said:

As its a switching supply I'm hoping that I wont need a relay to switch the motor on. see how it goes when it turns up.!

Click to expand...

I'm not sure what you mean. You will still need to switch the power to the motor so it doesn't run constantly. And you really shouldn't make the trigger action switch the mains on and off to a switching supply as they don't like frequent mains input cycling. Much better to have the mains connected right from the on/off switch and switch the output of the supply whenever the trigger is pressed.

This mod will make a big difference, getting rid of the up/down speed variation due to the arc current dragging the welding voltage up and down.

BillJ said:

I'm not sure what you mean. You will still need to switch the power to the motor so it doesn't run constantly. And you really shouldn't make the trigger action switch the mains on and off to a switching supply as they don't like frequent mains input cycling. Much better to have the mains connected right from the on/off switch and switch the output of the supply whenever the trigger is pressed.

Click to expand...

I see what you mean, wouldn't be a good idea really!

so to use a relay, i would use the trigger as the switch then right. I don't have a circuit diagram of the Topmig 150, any idea where I can find this I've looked on the forum without much joy.

M.

I sourced a 19.9v 4.7amp HP laptop charger so thought i'd plum it in and see how it goes till the proper 24v3a regulated transformer turns up.

Progress...
i bought an ac relay http://www.maplin.co.uk/Module.aspx?ModuleNo=37495 (N24AW) as BillJ did to switch the motor, i also used the schematic from http://www.mig-welding.co.uk/forum/showthread.php?t=11532&highlight=100 as a general guide.

Wired up the power supply so that it would supply 19.9v to the board in the welder (the wire that comes from the transformer cn5 to cn1), tried that and it seemed to work just fine, didn't make the motor run continually as i thought it would.

so then i tried to wire up the relay as per Bills schematic, did i have any joy? hell no! just couldn't get it to work, its such a simple thing too. you can see it switching as its clear but the terminals don't appear to do what they're supposed to, i feel really dumb! soon as i take it out of circuit then it seems to work ok.

I did do a couple of very short welds without the relay to see how it went and it seemed ok,
I'll have another look tomorrow as it got a bit too cold in the garage tonight!

Here's a pic of the welder...


M.

i think for sure i've wired something up wrong, i check voltages on the wire feed motor and its showing near 40v when power and wire feed dials are turned up. Guess i'll have to try and find a schematic of the topmig 150, might be more specific than i thought.

M.

SIPs seem to all use the same control board.
http://www.eddiem.com/projects/mig/speedfix.html
Robert

this is the circuit board in the topmig 150...



From the block on the left (cn1)
Black - looks like it goes to the thermal cutout, its on the main transformer
White - goes to the +ve side of the wire feed motor
Red - comes from the larger transformer and is live when the trigger is pressed, i've cut this and put the +19v from the laptop charger here.
Blue - comes from the torch trigger

From the block on the right (spade connectors)
First from the left marked 'R' - comes from the main switch and i've added a wire here to go to the relay ac side. for the same wire, i've taken another from the main switch side to power the 19.9v 3a laptop charger
Second 'S' - comes from the main switch and i've added a wire here to go to the laptop charger also.
Third 'T' - comes from the large transformer and switches when the trigger is pressed, i've taken a wire from here to the other ac side of the relay.

Relay works fine and click and all that, i'm not switching anything with the relay at the moment so its just powering and thats it..

The earth from the wire feed motor goes to a main earth, i've added the earth from the laptop charger here too.

Odd thing is the only dc feed going into the board that i can find is the 19v that i'm putting there with the laptop charger, yet the wire feed motor sees upto 40v at full chat! not sure whats going on there.

I've emailed tech support at SIP to see if they can send me a topmig 150 schematic diagram, that should help i guess!.

M.

Had another go on the welder and first impressions are good, the feed into the board was wrong, it should have been the black wire that i thought was the thermal cut out (obviously not now!) and not the red one. Voltage across the motor is 19v as it should be.

I see what you guys mean about the motor stopping dead with both terminals to earth using a relay it really is a noticeable difference in motor stopping!

I tried a couple welds, on panel steel it was good on power number 3 and speed 5-6, even tried holding the gun up to weld and still pretty good, much better than before. At full power setting 6, the wire speed is whacked up all the way and it seems to be enough for it, will be better once i get the transformer that's on order.

One thing I've noticed is that it doesn't step up the wire speed when you change power settings now, still, small price to pay i guess.

On initial trial I have to say, it seems a lot better on thinner steel than before.

I've left it for tonight still in bits, will close it up tomorrow and do some further testing for you guys to see.

M.

Well done. I have to ask, if at full speed it is good enough at full power, why would it be better with a different supply? The only reason I didn't leave my old laptop supply wired in was that it was only 16V and couldn't run the wire fast enough at full power. Were you using 0.6mm wire or 0.8? If 0.6 then that's as fast as you'll ever need it to feed.

You do lose the automatic scaling with power setting but as you say, it's a small price to pay for a smooth, reliable wire feed. That feature was achieved by running the motor controller directly from the welding voltage, which obviously increases as you increase the power setting. It was also responsible for the unstable feed since striking an arc lowers the welding voltage, which slows the feed, which breaks the arc, which increases the voltage, which speeds up the feed, which strikes the arc, which lowers the voltage ...

BillJ said:

Well done. I have to ask, if at full speed it is good enough at full power, why would it be better with a different supply? The only reason I didn't leave my old laptop supply wired in was that it was only 16V and couldn't run the wire fast enough at full power. Were you using 0.6mm wire or 0.8? If 0.6 then that's as fast as you'll ever need it to feed.

Click to expand...

Thanks man, there was a word missing "just" not done a full on test on full power just a brief one, will try tomorrow and post some pics of the results. I'm using 0.6 wire at the moment too. The supply is on order so it makes sense to use it when it turns up as that's what I bought it for! It was my impatience that made me use my old laptop charger

I did notice though that on low speed settings it sounded like the feeder motor was hitting a sticky spot in the cycle, this disappeared though as soon as I started to turn the speed up.

I'll get some 0.8 wire and tips tomorrow and see how they go too.

M.

Changed the wire to 8mm and did some tests...



I've circled and marked what power settings i did these at. Seems pretty stable until i get down to power setting 2 and 1.

The only way i can describe those 2 welds (1 &2) are like seeing Mr. Whippy coming out the torch! and that's no joke! this was on 3mm steel, even on panel steel it still did pretty much the same thing. Looked like it wasn't arcing but just heated the wire red hot and making it very pliable.

seemed to work lots better on the 6mm wire at these lower settings. Will put the 6mm back in tomorrow and run a few more tests.

With the 8mm wire and full power (setting 6) the wire speed at full seems a little too much, definitely better with the 6mm i would say, but i'll know for sure when i do some more tests tomorrow.

so far its looking like a 19.9v 4.7a HP laptop charger is the way to for a cheap cheap wire feed mod!

M.

themininut said:

Seems pretty stable until i get down to power setting 2 and 1.

The only way i can describe those 2 welds (1 &2) are like seeing Mr. Whippy coming out the torch!

Click to expand...

What gas? CO2? If so, even the Portamigs have trouble maintaining a stable arc with CO2 on low power settings. If Argon/CO2 mix, then there's still improvement to be made...

Are you saying that you are trying to lay a decent bead with the amps turned down ?
You need about 1 amp per .001 inch of material thickness, to make a decent weld.
3mm would take 110-120 amps.
And .8mm wire isn't really recommended below about 40 amps.
Or did I miss read what you were trying ?
Robert

BillJ said:

What gas? CO2? If so, even the Portamigs have trouble maintaining a stable arc with CO2 on low power settings. If Argon/CO2 mix, then there's still improvement to be made...

Click to expand...

I'm using argoshield so i hope theres gains to be made i've read on your mod thread that there is a trim pot on the board, how can i tell which one i have? i've already bought the 100 ohm on while i was in Maplins as it was only pennies when i bought the relay.

R Kraft said:

Are you saying that you are trying to lay a decent bead with the amps turned down ?
You need about 1 amp per .001 inch of material thickness, to make a decent weld.
3mm would take 110-120 amps.
And .8mm wire isn't really recommended below about 40 amps.
Or did I miss read what you were trying ?
Robert

Click to expand...

I did think that might be the case but wasn't aware of the numbers! so it seems the results are quite normal in that case for the thickness of material, power and size of wire I was using.

I will change to .6mm wire tonight and try the lower settings on panel steel and report back.

thanks for the feedback guys.

M.

Did some more testing tonight. Seems like this 19v 4.7a laptop charger has done the trick...





Images tell it like it is. couple things i found...

With 3mm plate, at the higher setting the 6mm wire was melting before it hit the puddle so kind of spraying into the steel, 8mm wire was better in this instance.

With the panel steel, i could use setting 1-4 without blowing or raised welds on the 6mm wire, on the 8mm wire there was quite some build up on the lowest couple of settings, but still usable even though you have to move quite quickly with either wire.

The welder seems to start playing silly boogers when it gets up to the duty cycle and then wire seems to judder a little, shame as its starting working nicely now.

I'll finish off my sills this weekend and see how it behaves then. I'm expecting something to go wrong else it wouldn't be a SIP welder wuold it

M.

SIP manuals seem to be a little scant on user info.
If you go to the Miller website and look up a similar welder, you can get some good info.
Page 25 may be helpful to you.:http://www.millerwelds.com/om/o1314a_mil.pdf
Robert

R Kraft said:

SIP manuals seem to be a little scant on user info.
If you go to the Miller website and look up a similar welder, you can get some good info.
Page 25 may be helpful to you.:http://www.millerwelds.com/om/o1314a_mil.pdf
Robert

Click to expand...

Thanks matey that's really helpful. now that the "step up" is gone for the wire feed, I need to label the dials on the welder with useful info rather than power 1-6 and wire speed 1-10! (why do they do that anyway)

M.

You could try Malcom's welder setting calculator, it seems to work well.:http://www.mig-welding.co.uk/calculator.htm
I've see a lot of welders with amps/wirespeed notes taped on them,or in the wire reel space.
Robert

Thanks R Kraft, another useful link

I managed to get the sills done on the weekend, have to say that its vastly improved from the last time. Generally no burn back or sticky nozzle with the gun inverted all the time. The wire was balling sometimes near that panel, but I expect that's down to not enough wire speed.

A very worthwhile mod and its cost me under £10 so far result! When the new transformer turns up it'll still only make it £27!

Still on the lookout for something better though, doing this mod just makes it less painful using the SIP until a better one is found.

Thanks for the help guys.

M.