Smoke fuse to Princess Elizabeth.

[Jorge-353264]

I tried your suggestion using the 5 amp fusewire 4 laps, but still shorted the loco. Should I use a 3 amp?

[Topcat2018]

Where and what is the original question?

[P-Henny]

@Topcat

This question relates to a previously discussed topic many years ago to do with repairing the heating coil of a Triang Synchrosmoke unit. In that previous old thread, it was suggested that using 4 turns of electrical 5 amp fuse wire would provide a working repair as replacement heating coils were no longer available.

The member posting this solution claimed it worked and been used successfully by him. But given the age of the previous solution thread I can only assume that modern fuse wire is different to the fuse wire available at the time of the original repair suggestion, given that no 'more recent' attempts to use this fuse wire solution have been reported as being successful on the forum.

P.S. As a first time poster, it looks like @Jorge didn't know how to quote the previous post he is referring to.

[Topcat2018]

I don't see fuse wire working. It has a very low resistivity as it is intended to carry current up to its melting point without significant voltage drop so if you apply the loco drive voltage to it you will either blow the fuse or the controller will current limit. I don't think modern fuse wire is significantly different from that used in the past.

What is needed is nichrome resistance wire wound around a suitable heat resistant former. You can buy this on Ebay. I haven't used one these smoke generators for years, but if I remember correctly they were wound on a fibreglass former that the oil would soak into with a metal cap at each end like a fuse.

Beyond that it would be a case of deciding what gauge of wire would be required and how many turns on the former. You don't want the smoke generator to take too much power by using thick wire or you risk melting the loco bodywork and maybe overloading the controller. I seem to recall that the wire in the old smoke generators was quite thin, possibly 36 SWG or thinner.

That's about the limit of my knowledge on the subject.

[ntpntpntp]

Definitely need to be using resistance wire not fuse wire.

There's a 4 page thread on RMWeb where the same fuse-wire suggestion was made and shown not to work.

Look on ebay for used but working X.549 elements, but be wary of the rather high prices asked by some sellers. Even 10 years ago the price was up to £20 for one. I've just seen someone asking £45 for a pair untested <gulp>

[Tony57]

Hi

Son of Triangman put a thread on this forum about re-wireing the heating element of sycrosmoke unit.

He and his dad were trained by Triang and Hornby on doing Loco repairs when there were local service dealers maybe if he reads this thread he could he could give the way to do it again.

[Topcat2018]

I no longer have any locos with a Synchrosmoke generator but I do have a brand-new-in-box R376 LMS Class 4P. that has an unsynchronised smoke generator. This has an element wound round what appears to be a piece of asbestos, fortunately totally enclosed. I've measured the resistance of the smoke generator element and it is 110 ohms, which should give you any idea of the gauge and length of nichrome wire you would need to make an element.

Unfortunately, the thinnest nichrome wire I can find is 38 SWG which has a resistivity of 61 ohms per metre, so you would need about 1.8 metres of this.

I have found some 0.1 mm Kanthal (Iron-Chromium-Aluminium) wire which has a resistivity of 173 ohm per metre, but you would still need about 0.8 metres of this. You can buy kanthal wire as coiled coils (like the filament in a light bulb; the wire is coiled then the coil itself is coiled). These are used in vaping but have a limited lifespan.

The only other possibility I can think of is to use a surface mount metal-film resistor mounted element down on a small PCB that will fit where the original element went, with a small piece of fibreglass wadding on top to absorb the oil.

[Topcat2018]

Does anyone know what type of oil is used in smoke generators? I've been looking at Hornby R521 oil and the prices are outrageous. It would need a very low smoke point so I guess it would have to be a vegetable oil, like unrefined safflower oil, unrefined sunflower oil or extra virgin olive oil.

[P-Henny]

Does anyone know what type of oil is used in smoke generators?

 

 

Google "Seuthe Smoke Oil", this oil can substitute the Hornby R521.

[JJ73]

@topcat I use 'Deluxe Materials' Living Steam Scent & Smoke Oil - for 90 Ml £14.00

See my vid :-

🚂

[The son of Triangman]

Resistance of Tri-ang synchrosmoke smoke unit elements are 33 ohms when in good fettle. The Hornby smoke unit fitted to the likes of the loco R.376 as TC described are a different kettle of fish. My original article should have said resistance wire not fuse wire, for which I can only apologise. The synchrosmoke element usually has 4 turns of resistance wire. I looked at having new ones made, but there isn't enough demand to make it viable.

Seuthe make the correct smoke oil for these units.

[Topcat2018]

Assuming that the synchrosmoke unit is connected direct to track power (it's not connected in series with the motor or something weird is it?) and it is 33 ohms it must be drawing 364 mA and dissipating about 4.36 W at 12 V and I can't image how thin the wire must be to get 33 ohms in only four turns. I wish I still had one of those units to experiment with.

I bet an HM2000 controller wouldn't be able to drive such a loco.

[The son of Triangman]

Unit is indeed connected to the track power, the red positive feed wire runs from the X.298 motor feed clip to a small paxolin plate with a tiny contact fitted in the paxolin plate, the negative is from the cast chassis. The X.298 is fed from the brown positive pickup plate wire.

364ma sounds pretty close. Working elements have a resistance of 33 ohms, if can vary down to 30 ohms but 33 ohms is the norm.

[Jorge-353264]

Thank you for the information about using nichrome wire 38g. I will give it a try and let you know.

[rpjallan]

I might have to give this a try also. I am currently overhauling my old Britannia with syncrosmoke R259S. I have an old element but I don't believe it works. I'll have to measure the resistance. Is it possible to refurbish the old element or do you have to cobble something together with the new wire?

[Topcat2018]

@JO

@RP

I'm happy to be proved wrong, but I will just repeat my previous concern that the resistivity of 38 SWG nichrome wire is only 61 ohms per metre so you would need roughly half a metre to achieve a resistance of 30 - 33 ohms as measured by Son of Triang Man. Even if the paxolin former measured 10 mm around (which I doubt) you would still need 50 turns.

I'm sure the actual wire used must be very, very much thinner than this.

I wouldn't want you to buy some 38 SWG wire then blame me if it didn't work. Even though I mentioned 38 SWG wire in the first place I quickly discovered it probably wasn't feasible, and said so.

[Potterton]

This might appear to be a daft question to some, but what sort of circuit does one need to set up to test one of the Tri-ang elements. (Electronics not being my strong point obviously!)

[Rog RJ]

Easiest is to use a multimeter on the ohms scale. If it's open circuit it is no good.

[Potterton]

Thanks Rog.

[rpjallan]

Well, I found my synchrosmoke element & having a very close look it is very fine wire. I cleaned mine up & it does indeed read between 30-33 ohms. Now all I need is the packing for inside the smoke box & some smoke oil. Just a note: I seem to remember these elements were red when they were new & this one is a very dark brown. I hope that's not a bad sign. Are these elements damaged if they are run with no smoke oil?

[P-Henny]

Are these elements damaged if they are run with no smoke oil?

 

 

The oil has a cooling property to limit maximum temperature. As an analogy think of it like trying to boil an electric kettle with no water in it. Not something you would normally choose to do.

[Topcat2018]

@RP

The element will naturally go darker with age because the heat is carbonising the oil, which is why you get visible smoke, the same as if you overheat oil while cooking..

[rpjallan]

I'm waiting on some parts for my Britannia but once they arrive I'll get the chassis together & see how it goes.