SIP 'IDEAL' 120 problem

[markh3565]

Hi - my first post on the forum - been reading through many threads with great interest.

Anyway I've an old style SIP 'IDEAL' 120 machine (cira 1982) cracking little welder - however not been used for many years and just started to do some welding with it - new wire/shroud/tip - wire feed motor good (industrial type etc) – new bottle of argoshield - obvious checks on basic electrics and connections etc.

From cold the welder strikes a crisp arc and sounds exactly as it should – the weld pool is good and generally and excellent slug of weld – however the symptoms are progressive as the welder rises in temperature before the thermal cuts in and shuts it down. So what happens after about 3 minutes of welding (without changing any settings) is the current fluctuates/pulses – it’s almost like when you set the wire speed too high – once this happens then it will not weld consistently but if you turn it off and let it cool for 10 minutes – again it work well for 3 – 5 minutes before it starts again.

Also if you touch the ‘job’ with the wire without pulling the trigger then it creates a small arc

So my question is – could this be a capacitor breaking down – a transformer – anyone any ideas?

Thanks and look forward to your assistance

Regards

Mark

 

[malcolm]

I found a useful thread with a circuit board diagram for a SIP Ideal 120N that is worth saving: http://www.mig-welding.co.uk/forum/showthread.php?t=6156

My guess would be a dirty contactor contacts - from the wiring diagram it looks like it should be a non-live torch which suggests contactor, and that's also involved in supplying the motor. Might have a plastic cover you can remove to clean the contacts.

A faulty capacitor could cause the problem. I had one go down on a different machine and it had the effect of doubling the wire speed after 1 minute of welding. If yours was the same problem you can measure the wire speed cold with a clock and a tape measure without needing to strike an arc. Bit of welding, measure it again hot.

Also well worth fitting a new wire liner after so many years - dirt, wear and rust in there can cause odd wire feed problems.

 

[markh3565]

Hi Malcolm - thanks for the info and link - cleaned up the contactor contacts and has certainly improved the problem - it now welds at higher amps for longer - however it does start to show the same signs closer to when the thermal cut out shuts it down - its almost like it increases/decreases in amps (hence the wire speed not correct ) probably increase as it tends to put a hugh amount on amps into the job

Wire speed seems ok when problem occurs - so capacitor problem???

The live touch issue seems to of disappread as contact with the wire on the job doesn't cause an arc - I'll replace the liner anyway - but certainly there is still a problem with it but it has transformed it back to its former self (well almost) - I'll see if I can replace the capacitor and a bit more cleaning of connections/ dry joints?

I've got the original blurb from SIP on the welder - i'll scan it at work next week and upload for reference

 

[Wozzaaah]

When a welder gets close to it's working temerature limit the arc gets very 'messy' and noisy.

If you are running it until the thermal cutout shuts it down then you need a bigger machine unfortunately. You will cause permanent damage to the machine if you constantly run it flat out (I speak from experience on that ).
It's not just the transformer that will overheat, the capacitors will too, and they could blow (experience again ).

 

[shenion]

It's not just the transformer that will overheat, the capacitors will too, and they could blow (experience again ).

These low-end MIGs have no capacitors

 

[Wozzaaah]

It still won't do any machine any favours running it until the thermal cutout activates though eh? If a welder has to be run flat out to achieve a desired result then it simply isn't powerful enough for the work it's being asked to do .

My personal experience is a 'mid-range' Butters 211 (220 amps), all you long-established members probably know my story, I bought it due to a claimed capacity of something like 8mm which I thought was ideal for the sort of work I was doing but in actual fact it was way underpowered due to the poor duty cycle. I ran it at full power for extended periods and did considerable damage to it .
While searching for a replacement machine I came across this forum, lurked for an hour or two then registered. After some advice from weldequip I bought a much bigger Portamig and haven't run it at anything over 2/3 yet and probably never will

 

[shenion]

Yes, hitting the limit will usually be bad on the very low-end machines. The thermal cutouts will likely fail.

My 130EN was nice. I never had it cut out and ran it hard. For DIY use, you spend enough time setting up the next weld to not hit the duty cycle. Even flat out, it seemed to stay real cool.

SIP's are known to be just cheap welders. You get what you pay for.

The PortaMIGs seem nice, but even they have a low duty cycle on their top end.

 

[markh3565]

These low-end MIGs have no capacitors

Not sure thats correct - as far as I'm aware back in the 1980 SIP built industrial spec welders - which the 120 N is - latterly you’re right they built the cheaper low end DIY welders that did not have capacitors - but this welder does as you can see from the photo

We seem to be deviating from the original post - the problem with the welder is that it cuts out after approx 3 minutes of welding on mid range settings (not on full power) which is not normal - the thermal cut out is kicking in before it should - if it were on full power then I would expect these characteristics - however the power rating is more than adequate for my reqiurements which is car body only - which leads me to think there is an electrical type problem?

 

[Wozzaaah]

It doesn't sound like the thermal sensor is faulty due to the fact the machine gives you warning of impending failure. Apart from checking all the internal connections are tight and checking for evidence of components getting too hot, scorchmarks etc. then I'm not sure what else to suggest. One thing is that the condition has improved slightly since you cleaned the contactor so maybe it needs a new one?
Might be worth PMing weldequip, he might have a better suggestion and might also have parts in stock to fix it.

 

[markh3565]

I've had a good go over the unit and taken the contactor unit apart completely and manged to swop the un used (new terminals) over inside the unit to the the used ones and visa versa - so the unit is now like new inside with all electrical contacts using the new terminal parts.

Again this seems to have improved the length of time that the unit will weld for - fiddling with the settings once it starts its irratic arc and wire speed if you up the power and the wire speed to the next setting it seems to then weld at the same amps and wire speed of the lower setting ( if that make sense??)

The smaller transfermer seems to get very hot in realation to the bigger one - this one has the termal cut out tucked in it - could it be the power switch or the wire speed switch at fault???

 

[mpranski]

ideal 120n inside pics

Hi guy, this is MVP again from across the pond. Does any one out there have an ideal 120n mig welder? I was able to salvage my rotary switch for the voltage selector. However, I am not sure if I crossed two of the transformer wires. There are 6 transformer wires going to the switch. On the bottom row they are numbered 3,2,1. on the top row, they are numbered 4, x, x. I almost thought they were numbered 4,6, & then 5?. It doesn't sound right. (sounds funny now, I wrote them down before I took it apart, but it was labor day & a little vodka was the culprit ). If anyone out there has one of these welders could you peek under the hood & let me know. Mine was made in 1984, & although it does not have the large capacitor as I saw one here pictured (what is it for) it out welds any miller or linclon 140, & then some . I even have been able to spray arc weld with it with .025 wire & a bottle of tri mix (called stargon over here). Any help i=on the pics would be great. Thanks, MVP

 

[octo0072000]

i would put a fan in there for starters that should improve the duty cycle i know there is not a lot of room in that case you could put a fan under the case to blow into the transformer

 

[mpranski]

ideal 120 n fixed

I got my mig up & running again. I put a multimeter on the ground & lead to the torch. I actually did write the wire leads down correctly on the rotary selector switch. They were 1,2,3,4,6,5. hope this may help someone in the future. Time to celebrate!

 

[wwheelock]

Really old thread, but I have an Ideal 120N that I purchased new in 1984. Recently the voltage selector switch has failed. Won't turn without way too much turning pressure and sometimes won't turn at all. Not having any luck finding a replacement switch. Anyone else ever replace these with something else? Here's some photos of the switch.

Thanks for any help you can provide.
Bill Wheelock

 

[eddie49]

Hello Bill and welcome to the Forum!
I think you win this week's prize for the oldest resurrection of a previous thread - 15 years!

In theory, you could contact SIP UK ( https://www.sipuk.co.uk/spareparts.html ) and ask them if they still have parts for this very old machine. It is unlikely, and, with shipping, would probably cost a lot more than the machine is worth.
The Post #2 by @malcolm which links to another SIP 120N thread shows that the rotary cam switch is a simple 1-pole 6-way switch. As such, it could be replaced by any generic 6-way switch of adequate current rating ( e.g. 10 or 20 Amps ), such as:

16a Electrical Rotary Switch Cam Changeover Silver Contact 3 Pole 0-6 Position | eBay

Current: 16A. Pole: 3 poles. Switch Type: Universal Switch. Position: 0-6 positions. Application: Motor Switch. Installation: Square Plate.

www.ebay.com

These "Bremas" rotary cam switches come fully configured ready-to-use. They are made-to-order for manufacturers of welders, but external jumper clips or wires may have to be added by the user. There is usually a listing or "truth table" included to show which terminal numbers are joined in each rotational position. So it's important to quote the exact model number from the specific switch when ordering it. There are many variations. It is a minefield....
The switch label should have a Bremas part number on it, such as "CSxxxxxxx" or "CAxxxxxxx", but often they are faded or worn away.
You could try contacting Bremas in Italy and send them full details of your switch ( model number, number of positions, number of switch segments or wafers ). Their Email address : info@bremas.it

These guys:
https://www.davron.co.uk/Comp1.html
https://www.davron.co.uk/BremasM.html
seem to know something about Bremas switches, and may be able to supply an equivalent.

It is normally not advisable to try to open or fix these switches, they tend to explode and spray springs, contacts, cams and ball bearings into the darkest corners of your workshop. However, since the fault on your switch seems to be mechanical, you may be able to carefully open the detent section at the front of the switch, and clean, inspect, and lubricate it, without disturbing the electrical contact section.

 

[wwheelock]

Thanks Eddie49. The only information I could find on the switch is in the photos. Could not find anything that looked like a part number. Did find other threads in these forums where they had contacted SIP and were advised no parts were available. Thanks for the link to the switch on ebay. I searched for quite a bit yesterday online and think maybe I found that switch. That switch has 7 positions with 1 being off, while mine is 6 with no off. Guess it should work, but I'm no electrical genius, so want to keep it simple for me.

I've had rotary switches apart before and like Humpty Dumpty they don't go back together again! May take another look at the front of switch though, to see if the detent could be accessed without the rest of the switch exploding.

Thanks again.
Bill Wheelock

 

[Windy Miller]

I once had an Ideal 160 (I think) with a dodgy voltage switch. I bought a replacement from my local welding repair guy. I don’t remember any specify issues with it other than the switch had one more position than the previous one.
Quite a simple repair if I remember correctly

 

[wwheelock]

I was able to take the front of the switch apart. The problem is not the detent. Has to be in contacts. May try to obtain the switch you linked to and change it out.

 

[eddie49]

I was able to take the front of the switch apart. The problem is not the detent. Has to be in contacts. May try to obtain the switch you linked to and change it out.

That sounds like progress, and a good plan.

If the electrical part of the switch is broken, and it needs to be replaced, then with nothing to lose you could try looking deeper inside the contact segments. First label everything! Personally, I prefer putting tie-on labels on all the transformer tapping wires. Don't be tempted to rely on memory, or only photographs.

I have always been baffled by these rotary switches, but recently I am starting to understand them. The eBay switch that I linked to has 6 active positions plus "Off". It has 12 terminals and three wafers or segments. So each segment contains two On/Off switches. The cams inside are positioned on the control shaft in a staggered row, so that as the shaft is rotated the switches close and then open, one after the other. I think the way they are arranged is that the first to close is on one segment, then when the knob is moved to the next position, that one will open and the next to close is on the adjacent wafer, further back on the shaft. That is why you see horizontal metal links, joining terminals on one segment to the one behind it.
To use a 6-position 12-terminal switch with six On/Off switches as a 1-pole 6-way switch, you have to link the 6 "moving" levers together, making the one "pole", and resulting in 7 working terminals.

Circuit diagrams of MIG welders, and new rotary cam switches, often come with a chart or "truth table" which shows all the terminal numbers and indicates with a line or an "X" which ones are joined in each switch position. For example:

Esab Miggy 125 - 220/380v

Hi guys, I purchased second hand Miggy 125 that is set on three phase (380v). I can see on schematics inside that it can be converted to 220V. Does it mean that I can just change shortcuts according to scheme and use it as a single phase welder? I assume that I have to change cable to monophase...

www.mig-welding.co.uk

„SPAW - SERWIS” - autoryzowany serwis spawarek i zgrzewarek

( sorry, that site is in Polish ... )

Hopefully, that eBay switch will come with a chart. If not, you will have to work it out with an Ohmmeter, since the terminal numbering will not match your original switch.

This thread about an issue with a rotary switch may be helpful background info:

ESAB (Snap-on) Smashweld 180 Stuttering

Hi All I'm taking a look at a mate's welder that was returned to him after lending it out. It needed a new torch and wire and given it was in a bit of a sorry state, initially he though the wire feed motor had packed up, but we think that's because he'd forgotten to put the front toggle switch...

www.mig-welding.co.uk

 

[Roberthansjorg]

Hello Bill and welcome to the Forum!
I think you win this week's prize for the oldest resurrection of a previous thread - 15 years!

In theory, you could contact SIP UK ( https://www.sipuk.co.uk/spareparts.html ) and ask them if they still have parts for this very old machine. It is unlikely, and, with shipping, would probably cost a lot more than the machine is worth.
The Post #2 by @malcolm which links to another SIP 120N thread shows that the rotary cam switch is a simple 1-pole 6-way switch. As such, it could be replaced by any generic 6-way switch of adequate current rating ( e.g. 10 or 20 Amps ), such as:

16a Electrical Rotary Switch Cam Changeover Silver Contact 3 Pole 0-6 Position | eBay

Current: 16A. Pole: 3 poles. Switch Type: Universal Switch. Position: 0-6 positions. Application: Motor Switch. Installation: Square Plate.

www.ebay.com

These "Bremas" rotary cam switches come fully configured ready-to-use. They are made-to-order for manufacturers of welders, but external jumper clips or wires may have to be added by the user. There is usually a listing or "truth table" included to show which terminal numbers are joined in each rotational position. So it's important to quote the exact model number from the specific switch when ordering it. There are many variations. It is a minefield....
The switch label should have a Bremas part number on it, such as "CSxxxxxxx" or "CAxxxxxxx", but often they are faded or worn away.
You could try contacting Bremas in Italy and send them full details of your switch ( model number, number of positions, number of switch segments or wafers ). Their Email address : info@bremas.it

These guys:
https://www.davron.co.uk/Comp1.html
https://www.davron.co.uk/BremasM.html
seem to know something about Bremas switches, and may be able to supply an equivalent.

It is normally not advisable to try to open or fix these switches, they tend to explode and spray springs, contacts, cams and ball bearings into the darkest corners of your workshop. However, since the fault on your switch seems to be mechanical, you may be able to carefully open the detent section at the front of the switch, and clean, inspect, and lubricate it, without disturbing the electrical contact section.

Hi Eddie49,
I'm new here.
My SIP Ideal120/N - had it a long time and it works fine except now it's started to buzz when I press the hose trigger and feed wire. Everything works as it should - it's just the rasping noise.
I opened the side and the noise comes from the trigger unit with the grey square button poking out. This button/rod goes in and out when I use the hose trigger. I can press this grey rod and wire feeds OK with no noise.
I don't even know what this internal trigger component is called.
Can you advise me please?
Robert