Relay help

[antighsiothail]

Hi
I need to replace the relay in my MIG welder, the company don't seem to be around now, so can't get a replacement from them.
I have added a photo of the relay cover, and also specs to the nearest I can find. Would really like advice as to if the one I've found will do the job, failing can anyone recommend a relay that will.The one I've found is listed on RS as Relpol R40N-3011-85-5220
Many thanks

 

[antighsiothail]

Apologies for the size of the photos.

 

[Harald Kapp]

The original relay has an 18 V DC coil, the replacement will have to have an 18 V coil, too. The one you found doesn't support 18 V.
Here's an example with 18 V DC coil and 40 A contact current.
Looks very similar to the one you showed.

 

[antighsiothail]

The original relay has an 18 V DC coil, the replacement will have to have an 18 V coil, too. The one you found doesn't support 18 V.
Here's an example with 18 V DC coil and 40 A contact current.
Looks very similar to the one you showed.

Thank you, I had hoped the one I found would work over a range of voltages, ah well. I'll try to find a UK source for the one you suggested, many thanks.

 

[Minder]

A tip.
It pays to remove the vent 'pip' in the middle of the relay, this is often sealed for flux cleaning of the board at manuf.
The removal, prevents premature failure due to internal ionization of the relay causing arcing of the contacts.

 

[Harald Kapp]

The removal, prevents premature failure due to internal ionization of the relay causing arcing of the contacts.

On the other hand it provides a path for environmental agents (gases, humidity etc.) to enter the relay and corrode contacts.
We use only sealed relays at work and they endure 10 years and longer.

Arcing of the contacts can be mitigated by e.g. a 2.2 nF or 4.7 nF X1/Y1 capacitor across the pins leading to the contacts.

 

[Minder]

Here is one Manuf. sheet on it.
Also another manuf also says vent unless corrosive gasses are present in its environment.