SIP 'IDEAL' 120 problem

[eddie49]

Hello and welcome to the Forum !

That component is the contactor. It is a large heavy-duty relay. It is operated by a solenoid coil, at 12 or 24 volts, controlled by the torch trigger switch via the small printed circuit board. The coil moves an armature which carries a set of two or three contacts. When these close, they feed AC mains to the welding transformer. The gas valve and wirefeed motor also operate at that time.
The coil and armature can attract magnetic grinding dust, which may be causing the buzzing noise. You could start by removing, opening, and cleaning the contactor. If this does not help, it can be replaced by any similar generic contactor - it's not a unique SIP part.
Start by switching off and unplugging the welder. Make a full and careful note of all the connections to the contactor. Do not rely on memory or photographs! The terminals should have numbers already, such as L1, L2, T1, T2. The coil terminals may be A1 and A2. If the wires are not already numbered, I prefer tie-on labels.
The contactor may be held together with spring clips, or just detents in the plastic. Remove any dust or grease, clean the moving and fixed contact faces with fine abrasive paper, re-assemble and test!

 

[Windy Miller]

Hello and welcome to the Forum !

That component is the contactor. It is a large heavy-duty relay. It is operated by a solenoid coil, at 12 or 24 volts, controlled by the torch trigger switch via the small printed circuit board. The coil moves an armature which carries a set of two or three contacts. When these close, they feed AC mains to the welding transformer. The gas valve and wirefeed motor also operate at that time.
The coil and armature can attract magnetic grinding dust, which may be causing the buzzing noise. You could start by removing, opening, and cleaning the contactor. If this does not help, it can be replaced by any similar generic contactor - it's not a unique SIP part.
Start by switching off and unplugging the welder. Make a full and careful note of all the connections to the contactor. Do not rely on memory or photographs! The terminals should have numbers already, such as L1, L2, T1, T2. The coil terminals may be A1 and A2. If the wires are not already numbered, I prefer tie-on labels.
The contactor may be held together with spring clips, or just detents in the plastic. Remove any dust or grease, clean the moving and fixed contact faces with fine abrasive paper, re-assemble and test!

Well done for a very detailed explanation!

 

[Shedendman]

Well done for a very detailed explanation!

Indeed,because if you mess it up you're in a world of hurt

 

[eddie49]

In Post #14 of this thread there is a circuit diagram of the SIP Ideal 120N welder ( and of the PCB ):

SIP Ideal 120 Blowing panel fuse

Good afternoon, I have the good (?) fortune to own a MIG welder that is nearly as old as me, and with the exception of renewing the torch every couple of years it has given me faultless service for years, until a couple of days ago. Mid-weld it just stopped and paying a bit of attention...

www.mig-welding.co.uk

It shows that the contactor operating coil is in parallel with the solenoid coil of the gas valve, and they are both driven by AC from the auxiliary transformer. Not sure of the voltage - probably 24v AC ? This may be marked on the contactor coil, or a small tag attached to the A1 or A2 terminal.
Control of this voltage is a simple series circuit direct from the torch switch. There is also a thermal overload cutout in series.
If the contactor itself is not faulty, as discussed in my Post #21, then maybe there is a bad connection in this control circuit.

 

[Roberthansjorg]

Hello and welcome to the Forum !

That component is the contactor. It is a large heavy-duty relay. It is operated by a solenoid coil, at 12 or 24 volts, controlled by the torch trigger switch via the small printed circuit board. The coil moves an armature which carries a set of two or three contacts. When these close, they feed AC mains to the welding transformer. The gas valve and wirefeed motor also operate at that time.
The coil and armature can attract magnetic grinding dust, which may be causing the buzzing noise. You could start by removing, opening, and cleaning the contactor. If this does not help, it can be replaced by any similar generic contactor - it's not a unique SIP part.
Start by switching off and unplugging the welder. Make a full and careful note of all the connections to the contactor. Do not rely on memory or photographs! The terminals should have numbers already, such as L1, L2, T1, T2. The coil terminals may be A1 and A2. If the wires are not already numbered, I prefer tie-on labels.
The contactor may be held together with spring clips, or just detents in the plastic. Remove any dust or grease, clean the moving and fixed contact faces with fine abrasive paper, re-assemble and test!

Thanks very much Eddie. And thanks every one else for the welcome.
I'm repairing an exhaust on my Rav4 Mk2 at the moment. I'll finish that first - it's intermittent welding and but for the noisy buzzing the welder works as it should.
Then I'll have a go at cleaning the contactor as you suggest. I'll definitely record the wiring before hand.
I'd be grateful if you could recommend a generic contactor for this welder. I'm glad it's not unique to this SIP machine.
Is there anything I could refer to before disassembling the contactor? I've never tackled something like this before but I have repaired Makita 18v screwdrivers before and I'm handy with a multi meter.
Electronics is something I'm happy to tackle. I can solder as well. I relish the challenge of doing it myself rather than handing over to someone else. I repair my own car as well.
And yes - this welder will be unplugged when I start work on it.
Thanks again- Robert, Stroud.

 

[eddie49]

For example, here's a generic 3-pole contactor:

Pardon our interruption...

It has a 24 volt AC operating coil, but until you check yours and hopefully find a voltage label, we cannot confirm the required coil voltage. If necessary, the gas valve ( which is in parallel with the contactor ) may provide this information, or of course you could measure the AC voltage supply at the auxiliary transformer. That transformer has two secondaries. One supplies the contactor and gas valve, the other runs the wirefeed motor via a controlled bridge rectifier ( with two diodes and two SCRs ) on the PCB.

On the original contactor, the clips or clamps that hold it together should be fairly self-evident. Since this component is quite old, it may use self-tapping screws to hold the plastic parts. It will sort-of come apart in layers, with the top plate, the fixed contacts, the armature, and a coil spring somewhere... When putting it all back together, the spring is there to push the contacts apart when the coil is de-energised.

EDIT:
The circuit diagram that I linked in Post #24 above shows that the contactor has one set of Normally-Closed ( NC ) contacts which short the wirefeed motor when it is idle. This causes the motor to stop rapidly, preventing run-on of the welding wire spool. The contactor I quoted has a Normally-Open ( NO ) auxiliary contact, so actually it is not suitable. If a replacement is required, we'll need to find one with an NC auxiliary contact.

 

[Roberthansjorg]

Hi Eddie49,

K1/23, 48v,50Hz is burnt into one of the connections to this contactor.

I can send more pictures if you'd like. I'm guessing it has a 48v coil so I'd need to
replace this contactor for one with the same spec.
Any suggestions?
I've finished the welding job I had to complete so when the weather improves I'll
start to plan the removal of this contactor and attempt to clean it.
I'm learning however that cleaning may not be enough and this is an old machine
after all. Still very use-able though. Replacement machines of this spec start at £500
and are not built as well.
Robert, Stroud.

 

[eddie49]

Hello Robert,
Post #2 in this thread:

Can you identify this little MIG? IDEAL 120 / N

Has ANYone here ever seen a welder like this? Its Old.... Used to work great until..... The wire feed circuit board is *snif* .... dead. Here are some pics. What I really am hoping for is someone on this forum will see this and say " I got just the part you need." Well...

www.mig-welding.co.uk

suggests that the wirefeed motor on the SIP Ideal 120N may be 48v, so it is possible that the contactor is as well. If so, I guess that coil voltage requirement would make sourcing a new contactor slightly harder. We would be looking for one with 2 or more poles, one NC auxiliary contact, and a 48v AC coil. Here is a rather expensive example:

https://www.cef.co.uk/catalogue/products/281642-25a-contactor-4-pole-48v-coil-ac1

Let's hope that cleaning the original fixes the problem!

 

[Roberthansjorg]

Thanks Eddie49,
That's very helpful. Once I've removed the contactor properly I'll be able to photograph it all round.
There may even be a proper label tucked away out of sight.
I'd pay for that expensive Schneider contactor because the alternative is far more expensive.

I phoned SIP in the UK and asked what would a similar spec'd MIG welder cost me today and I was quoted
a ridiculous price and model. She even told me they don't build them as well as the "old" ones these days!

There's a guy on E-Bay called yorweldsupplies (6155) selling contactors described as follows @ £42 each:

MAIN POWER CONTACTOR / RELAY FOR MIG WELDING MACHINES​

THIS CONTACTOR CAN BE FITTED TO MOST MIG WELDING MACHINES UPTO 300 AMPS SINGLE PHASE OR 450 AMPS 3 PHASE.

CONTACTOR SPECS

3 X NORMALLY OPEN CONTACTS
1 X NORMALLY CLOSED CONTACTS (can be used to discharge capacitors on single phase machine)
40 AMP AC1 RATING (25 AMP AC3)
11KW RATING
COIL VOLTAGES AVAILABLE: 24VAC, 42VAC, 110VAC, 230VAC, 400VAC

He says the 42v contactor is actually a 48v contactor.

What do you think?
Robert










(PLEASE CHOOSE WHICH VOLTAGE CONTACTOR YOU REQUIRE WHEN ORDERING FROM THE DROP DOWN MENU ABOVE)





OTHER CONTACTORS WITH HIGHER RATINGS AND MORE CONTACTS ARE AVAILABLE. PLEASE CONTACT US FOR DETAILS

 

[eddie49]

The eBay Seller "yorweldsupplies" is the company "Technical Arc Ltd.", known as Tec Arc. They have a wealth of knowledge and experience, and are the makers of the well-respected Portamig and Oxford brands of MIG welders. I am sure that they can supply the correct part, and it will be of good quality.

 

[Roberthansjorg]

Much obliged Eddie49.
Once the freeze is over I'll tackle this job and report back.
Found the label on the machine!
Best wishes
Robert,
Stroud

 

[Nix2]

MAIN POWER CONTACTOR / RELAY FOR MIG WELDING MACHINES... 11KW RATING...

This is much too strong a contactor for such a small semi-automatic device, but of course there are no obstacles to using it. Here, a contactor with a switching power of 4 KW would be sufficient, and this one has a power of 11 KW.

 

[Roberthansjorg]

I finally extracted the old contactor. On right picture 3.
Picture one shows black wire from power switch- went to contact 2 on old contactor.
Brown wire went to contact 6 on old contactor
Where do I connect these on the new contactor- 2/T1, 6/T1?

I've labelled everything and taken plenty of pictures. Hopefully someone can walk me through this conversion.
Many thanks.

 

[Roberthansjorg]

Hello and welcome to the Forum !

That component is the contactor. It is a large heavy-duty relay. It is operated by a solenoid coil, at 12 or 24 volts, controlled by the torch trigger switch via the small printed circuit board. The coil moves an armature which carries a set of two or three contacts. When these close, they feed AC mains to the welding transformer. The gas valve and wirefeed motor also operate at that time.
The coil and armature can attract magnetic grinding dust, which may be causing the buzzing noise. You could start by removing, opening, and cleaning the contactor. If this does not help, it can be replaced by any similar generic contactor - it's not a unique SIP part.
Start by switching off and unplugging the welder. Make a full and careful note of all the connections to the contactor. Do not rely on memory or photographs! The terminals should have numbers already, such as L1, L2, T1, T2. The coil terminals may be A1 and A2. If the wires are not already numbered, I prefer tie-on labels.
The contactor may be held together with spring clips, or just detents in the plastic. Remove any dust or grease, clean the moving and fixed contact faces with fine abrasive paper, re-assemble and test!

Hi Eddie, I'm back on the job finally. Taken out the old contactor - plenty of labels and pictures taken. The old contactor just has 2/4/6 front contacts and 1/3/5 contacts at the back and other none labeled contacts top front and top back. I know where all the wires go on the old contactor - just want to know where they go on the new contactor.

 

[eddie49]

Hello Robert,
The new contactor is a generic 3-phase unit, so it has 3 pairs of On/Off ( Normally-Open ) contacts, although your welder only uses two of them. We can chose to leave the centre pair of contacts - 3/L2 and 4/T2 - unused.

It is customary to connect the terminals labelled "L" ( Line ) to the input power and "T" ( terminus ) to the load. On this single-phase circuit there will be two inputs ( Live and Neutral ) - e.g. L1 and L3, numbered 1 and 5. Then the two outputs, T1 and T3, numbered 2 and 6, will supply the main transformer. If the position and length of these four wires means that you have to connect them "the other way up" ( i.e. power entering the contactor at "T" and the transformer connecting at "L" ), then that's fine, it is just a double-pole On/Off switch so it will still work. I think that is how the wires were arranged originally?

Referring to the circuit diagram in Post #14 here:

SIP Ideal 120 Blowing panel fuse

Good afternoon, I have the good (?) fortune to own a MIG welder that is nearly as old as me, and with the exception of renewing the torch every couple of years it has given me faultless service for years, until a couple of days ago. Mid-weld it just stopped and paying a bit of attention...

www.mig-welding.co.uk

there should be two AC mains wires ( one of which is the black wire from the main switch that you mentioned above ), and they should be connected to 1/L1 and 5/L3 ( or 2/T1 and 6/T3 if wiring in "upside down" mode due to wire lengths, as mentioned above ). This is AC mains, so the order between these two wires, L1 or L2 or vice versa, does not matter.

On the output side of the contactor, one wire goes straight to the transformer primary ( so it is probably solid copper ), the other feeds the transformer via the moving pole of the 6-way rotary switch.

There are 4 more connections to the contactor. Two of them are the 48v operating coil at A1 and A2, and the other two are the circuit that shorts the wirefeed motor to halt it quickly, going to the two "NC" contacts at 21 and 22. At each of these two locations, the order between the pair of wires and the two available terminals does not matter.

 

[Roberthansjorg]

Hi Eddie, Thanks for replying. Please bear with me. I'd like to take this step by step.
The new contacter can be fitted same way the old one was on the backing plate so wire length not an issue.
In pic 1 the black wire came from the 4 position rotary switch (1-4) Where should that go now on the new contactor?
In pic 1 the brown wire comes from the primary transformer. Copper. Where should that go now?

These wires went to 2 and 6 on the old contactor.

 

[eddie49]

Sorry to have wibbled on for so long in my answer....
The black wire should go to 2/T1 on the new contactor.
The brown wire ( solid copper ) should go to 6/T3 on the new contactor.

 

[Roberthansjorg]

Great stuff Eddie,
Before my Ideal 120/N got noisy I didn't even know what a contactor was.
I'm sending you some more pictures for your perusal.
Turns out the original contactor is German made. It's got "links"/"rechts" plastic stamped on top. Left and Right in English.
First step taken.
So the next step is re the contactor front - where does the Blue/grey wire combo go on the new contactor?
And then where does the Green/Brown wire combo go on the new contactor?
Picture no. 7 is what I'm referring to on the original contactor.
Best wishes
Robert

 

[eddie49]

I have been trying to resolve the contactor wiring based on the circuit diagram, the wire colours, and the pictures in this thread:

SIP Ideal 120/N

Another 1980s welder acquired at the weekend. Listed as having wire feed problems so needing a new torch, unused for years. The liner was missing. These old Italian MIG welding cable are like a big co-axial cable, so the wire was presumably trying to feed down the central plastic tube for the...

www.mig-welding.co.uk

but they do not match. I think there may be a screw-terminal connecting strip between the wires around the contactor and the plug on the control board.
Since one of the remaining circuits to be connected is a dead short ( the Normally-Closed contacts that brake the motor ) and another is the AC mains feed, this has to be correct! Could you please post a photo showing the origin of the Blue/Grey and Green/Brown wire pairs?

 

[Roberthansjorg]

Hi Eddie,

More pics as requested.

(Blue/Grey combo) Blue originates from left connection on the wire motor drive.
That's a black sleeve over the blue wire. Photo no.1.

Grey goes to the small PCB (wire speed?) Green box third wire down.
Photo no.2.

(Green/Brown combo) The Brown is actually black - but no matter.
Green wire originates from the blue box integrated with the gas valve below it.
The green wire on the left of picture.
Photo no.3.

The Brown/Black wire of this combo goes to the white connection box
on the other side of the welder where the wire feeds from.
Bit of red tape to mark it. Photo no.4.
The wire/s from the top of the white connector box feed into the base of the
welding hose alongside the gas delivery hose. Photo no. 6.

Thanks for your help Eddie.

Best

Robert