what's this?

[dutchman]

I took off the cover of my lincoln invertec v200 tig. All looked well, except for these two green cilindric things. The isolation is a bit cracked. I haven't got a clue what it is, what it does, or whether these cracks could be dangerous. They are connected to the print with a cable and the connection reads d4.
I tried google with the inscriptions:
sir 9618
src/f 30100
50 ohm j 80 W
but no success.

Anyone have a clue what these green things are??

 

[scotb]

?

50 ohm resistors?

 

[Wozzaaah]

how big are they? the photo makes them look huge.

 

[Wozzaaah]

50 ohm resistors?

Yes, they certainly are, I've just spotted them in the V200 manual. 50 OHM 80 W Resistor (Faston Terminal) part no. S24105-4. Well done Scot .

 

[scotb]

?

looks like its only the paint thats cracked, they will get hot when in use. wot you in there 4 anyhoo?if it aint broke dont fix it!!!

 

[dutchman]

Yes, they certainly are, I've just spotted them in the V200 manual. 50 OHM 80 W Resistor (Faston Terminal) part no. S24105-4. Well done Scot .

I am not very good at reading those things :full

Think I'll be able to find it now. Thanks!

looks like its only the paint thats cracked, they will get hot when in use. wot you in there 4 anyhoo?if it aint broke dont fix it!!!

Just checking for piles of dust or other weird things, like cracked covers, paint or whatever the green stuff is.

 

[dutchman]

Yep, found em, they're just a couple of big resistors.
So some cracked paint probably won't be a problem.

 

[shenion]

Those are 50 ohm 80W Vitreous Enamel wirewound resistors (or epoxy coated.) Could have been overtightened to cause the cracking. Usually the coating will turn brown if overheated, so does seem like something mechanical.

My Airco has nearly a dozen of them; from 10 watt to 200 watt (nearly 10" long).

They look fine. Just be careful if the coating flakes off. Besides a shock hazard, the wire can be very fragile.

If the invertec uses sparc gaps, be sure they are adjusted properly. My Airco was not maintained, so the gaps were 2x normal size. That burned out one of the resistors and some HV caps.

 

[dutchman]

Thanks for the advice Shenion.
The coating is chipping off a bit and the base metal is visible underneath the cracks. Don’t see any wires though, just a metal casing. Could this mean (increased) shock hazard and can the resistors be re-coated or insulated?

 

[shenion]

You can see the ridges where the wires are; there is nothing on the ends. Looks ok as far as a shock hazard. I would not worry about it unless you plan on having you hands in there with power on .

Don't know what you would coat it with, must be able to handle heat. The coating is similar to enamel (glass) that is fired. Epoxy would probably melt.

 

[dutchman]

You can see the ridges where the wires are; there is nothing on the ends. Looks ok as far as a shock hazard. I would not worry about it unless you plan on having you hands in there with power on .

I learn't the hard way that it's not wise to stick my hands in anything electric with the power on, so I don't plan on doing that.
Guess all will be ok as long as I don't see any funny wires or smoke coming out .