high frequency track cleaning for DCC

[Guest Moria]

Has anyone used one of these? Electrak3 Cleaner

 

Now theres a box version, I am considering mounting one and having it switchable in or out since it claims its safe for DCC.

 

I would like, however, to know if anyone has actually used one.

 

Regards

 

Graham

[amdaley]

Do NOT use any high frequency track cleaner with DCC. They are bitter enemies.

[Etched Pixels]

Has anyone used one of these? Electrak3 Cleaner

 

Now theres a box version, I am considering mounting one and having it switchable in or out since it claims its safe for DCC.

 

I would like, however, to know if anyone has actually used one.

 

Regards

 

Graham

 

I would be incredibly incredibly cautious about this. There are a couple of problems with the relco style of cleaner and DCC. The first and obvious one is that it interferes with the DCC signal when in use. That can fixed and presumably this unit has fixed it. The second is more insidious - silicon chips not only don't like higher voltages (hence the fact you are supposed to take static precautions updating a PC) but they can gradually get damaged even by the most momentary of discharges. It could be all the modern decoders have enough protection on the power side to clamp any spike fast enough.

 

That isn't something you casually test IMHO, it's something where you have to go do the maths with the vendors of the decoders because if it is a problem it will happen over time and only in some cases (just like ignoring the antistatic precautions on a PC often works providing you don't do it too often). I would ask the decoder vendors what they think of it if you want a more cautious asessment.

[Suzie]

It looks like it should be OK in practice since it is current limited to 2mA and most decoders will draw more than that even while idle (typically 10mA or more) due to the regulator maintenance current. You could put a 4K7 resistor between the red and black wires of your decoders to make sure that they will not go above their safe voltage while 2mA is applied if you have any that do not draw 2mA.

 

The theory is sound as long as it does what it says it is supposed to do! The mobile version works and is a lot less risky but does not fit the loading gauge very well (too tall and the steps foul the bogies).

 

 

 

 

 

[bertiedog]

The old Relco( and I assume the Gaugemaster) is safe with DCC if limiting resistors, and modifications are added, it is the key to the new commercial units that the current is limited by a very fast acting current regulator, and if working, ( the HF unit, not the Chip), the chips will be quite safe at these currents, despite the high voltage.

 

These are not really new, the principle on DCC has been known for some time, but I never mentioned it in previous postings, as it might cause great confusion and lead to an un-modified unit being used with DCC.

Now a confession, I have used Relco for about two + years with DCC, no problems at all, and clean track, but it is modified to reduce the output and has a limiting circuit added internally, ( FET discrete components, not a chip regulator, making a high speed current limiter). It's operation was studied on a scope to set operational speed above the frequency of the Relco and similar signals.

 

I don't wish to post the circuits openly, it might lead to claims about blown chips all over the place, as the use and assembly is so outside my control, so it would be best to use the new US based design, fully tested with all NMRA compliant DCC products, (I believe that they have applied for NMRA compliance as well).

 

I fully know Relco is still very contentious after all these years, I have used them since day one, and commercially, and at home, and have a 100% satisfactory performance from them, no blown coreless motors, no blown PC track, no blown commutators, no failures of power supplies, and now no troubles with DCC, as long as the modifications are done.

I cannot recommend the particular maker from direct experience , but it seems that they are able to provide the Relco operation with DCC without the troubles, as expected by myself and other users who have always had good operation from them in the past. The unit is not exactly cheap, but all the indicators are it works.

 

Stephen.

[bertiedog]

With reference to an earlier posting, it is suggested that using these new type devices might not blow the decoders, but might blow the actual DCC controller.

 

I did not immediately answer this, as it needed a bit of very careful consideration, but on such reflection I cannot see any way that any conventional DCC output stage would be affected by the signal being present across the feeds.

 

The US unit has as a separate power supply as well, and all that will be there in the output stage would be spurious AC voltages, filtered by the output stages damping factor, which cannot return into the DCC stages in any way. The output stages resist EMF spikes and back EMF etc., easily.

 

The signal is degraded a bit, but the error correction handles this along with all the other jitters and junk on the rail feed to the DCC decoders.

 

But it is all up to the user, DCC and Relco do not mix unless modified. so if you are still uncertain, then just use plain DCC. after all the use of DCC is meant to help get the signal through the dirt to the loco.

Relco works to remove tarnish, it does not clean messy, oily or dirty track, it still needs a wipe over to clean oil and mess, but once clean it will keep locos running., but on a heavily used DCC layout this would occur naturally anyway.

 

Stephen.

[Lady_Ava_Hay]

I haven't used one. I do know that the Relco is specifically excluded from DCC but uses the same principles.

 

Since the DCC signal is superimposed on the track voltage and this unit uses breaks in the track power and switching on and off, high currents, I suppose it will depend on the instant switching of these voltage spikes.

 

For the money, one could buy a couple of mechanical cleaning aids like the Dapol (which I do have) and not have to trust to lady luck and sophisticated electronic switches that, one day, might just be a millisecond too fast or slow.

[47707 Holyrood]

Taken from the DCC Supplies website for those who couldn't be bothered reading..

 

The popular Electrak 2 now has a fixed version, the Electrak 3.

This DCC Compatible track cleaner works just like the popular DC only high frequency cleaners, but is safe to use with DCC equipped locomotives.

 

We have tested this device with popular decoders, (including sound) without any problems!

 

The Electrak works by generating a high voltage, high frequency signal that is current limited to about 2 mA.

Due to the current limit, almost anything that is attached to the rails (e.g. a motor in DC or a decoder in DCC) will act as a short circuit to the Electrak. Thus, loads on the rails normally short the generated signal. Current flows from the generator, out one wheel set, across the rail load, into the other wheel set, and back to the generator.

Due to the low impedances involved, there is very little voltage in this loop (hence its safety and compatibility with DC and DCC). When the Electrak encounters a spot in the track that does not provide a good connection to the Electrak wheels (i.e. a dirty spot), the full 216 volts of the generator appears across this high impedance.

This high voltage acts to break up the contamination, and thus clean the track.

 

The Electrak is particularly good at destroying oxide films. Any exposed metal will form a surface oxide coat. Some of these metal oxides are insulators (such as brass) while some oxides do have conductive properties (such as ???nickel silver??? rails). Most metal oxides, however, do not conduct as well as the base metal. This is why abrasive pads work well. The abrasive action destroys the oxide coating allowing metal contact to the engine wheels. The dielectric withstanding voltage of thin oxide layers is on the order of 10-50 volts depending on the oxide and the oxide thickness. The Electrak has sufficient voltage to ???punch through??? the oxide (called defritting), destroying the oxide and exposing the base metal. The ability of the Electrak to remove track oxides is particularly handy if you have an outside layout or one exposed to high humidity.

 

 

[Guest Moria]

Thanks so much to all.

 

Theres always pro's and cons with any system, but I m gratified to read the response by bertiedog.. thank you.

 

As it happens, I rely on multiple cleaning methods as I have a fair amount of hidden track. I DO use a CMX and have ordered a Dapol unit (this is all N gauge by the way), but I do remember in the good old days of DC that sometimes, theres something that just needs a kick and a relco did that. The relco was also excellent if a piece of crud got between a wheel and a pickup, which the rail cleaners wont get.

 

I will probably order one and try it out and if any good or bad results, will report back here.

 

Thanks again bertiedog, not just for the report, but the explanation as well.

 

Regards

 

Graham

[Etched Pixels]

We have tested this device with popular decoders, (including sound) without any problems!

 

If they ran locos with it for a bit that isn't testing as I said before. Voltage spikes damage silicon devices that are not designed to take them, even very short ones. The damage can be gradual and insidious. It really will depend what the decoder is designed to handle and how it handles sudden short (relatively) high voltage spikes

 

The people you ask are almost never the people selling the product, it is the people whose product it will be used with. So I would suggest anyone with doubts asks Lenz, Digitrax, Hornby and/or Bachmann or whoevers decoders they use whether it is safe to use with their hardware and whether it will invalidate the warranty on the decoder.

[bertiedog]

Well... whilst I was designing the modifications to both the Relco and a home made version of HF cleaners, I contacted a leading supplier in Germany, who I cannot name, and they confirmed that the system is safe with suitable precautions.

 

However as usual with the continental makers, they refer to the original idea of DCC have a sufficient standing voltage to over come dirt on the track, and extra cleaning would be not needed. The arguement is that the mark space digital signals will get through to the loco, and give control, but the current required to propel the loco has to arrive at the loco, and the tarnish etc., may reduce the power available, and the HF unit may help maintain contact.

 

They do chips that overcome this in a different way, but confirmed that the DCC signal is not affected by the HF one, as long as strictly current limited, and of short duration.

 

The silicon chips do not deteriorate or age with high voltages, the main trouble possible with a HF unit is the use of modern lead free high tin solder, which can cause a condition known as "whiskers", minute crystals of metal that could short tracks out on PC boards of the decoders.

 

The HF cleaner signal could jump the gaps more easily, but the input stage of the chips are designed to damp such voltages, and the chips are protected with Zener inputs, there to stop static and handling voltages.

 

I was also told that makers had made tests with the chips in the States and all worked with the HF systems very well. They were testing it to see what would happen. I believe that the NMRA have an application for conformance for these US commercial devices and are looking in to it.

 

As I said before I cannot really publish the circuits, they might or might not work with all chips and I cannot be responsible for mass destruction of the UK MR communities chips!! However the US supplier is able to offer the same option commercially, and I can see the way the unit operates.

 

There are still those around who refuse to believe the Relco worked at all, and do not understand the operational details for DC use , let alone DCC. I have heard everything from destruction of a complete model to one bursting into flames due to the devices, frankly impossible. I have heard descriptions of the action as using ultra high static voltage to Zap the dirt at over 2000 vac......and one man blamed the demise of his Hi-Fi on one of them.

 

All I can say is that they work, as does the equivalent circuits, understandable operation, and yes, DCC will work with reservations, but if you want peace of mind do not use them...... Horses for courses......

 

Stephen.

[Etched Pixels]

The HF cleaner signal could jump the gaps more easily, but the input stage of the chips are designed to damp such voltages, and the chips are protected with Zener inputs, there to stop static and handling voltages.

 

I was also told that makers had made tests with the chips in the States and all worked with the HF systems very well. They were testing it to see what would happen. I believe that the NMRA have an application for conformance for these US commercial devices and are looking in to it.

 

Thats good to know - both that at least some of the decoders have proper fast acting protection and that the NMRA is working on some kind of conformance. Relco type systems have their uses in small scales especially with things like short wheelbase industrial locos.

 

Alan

[Dagworth]

The Electrak works by generating a high voltage, high frequency signal that is current limited to about 2 mA.

Due to the current limit, almost anything that is attached to the rails (e.g. a motor in DC or a decoder in DCC) will act as a short circuit to the Electrak.

 

 

 

Presumably this unit would not work with stock that has resisted wheel sets present on the track, or on systems that had more than one loco on the track, the high voltage would never be generated as there will always be some form of continuity across the rails.

 

Relcos were always fitted one for each controller so were only ever (normally) trying to power one loco at a time, in DCC this situation is very rare as all locos share the same power source.

 

Andi

[Suzie]

Damage to silicon devices can be cumulative. When a silicon junction is subjected to a higher voltage than it can withstand the insulation breaks down and suffers a small amount of damage. Eventually when subjected to enough abuse the insulation becomes sufficiently compromised that the device fails - usually as a short circuit.

 

Just because a decoder survives once does not mean that it has been properly protected. Even Zener diodes can be a little slow to react to a sudden application of high voltage and fail.

 

 

[bertiedog]

Presumably this unit would not work with stock that has resisted wheel sets present on the track, or on systems that had more than one loco on the track, the high voltage would never be generated as there will always be some form of continuity across the rails.

 

Relcos were always fitted one for each controller so were only ever (normally) trying to power one loco at a time, in DCC this situation is very rare as all locos share the same power source.

 

Andi

 

This was always a little understood bit of the operation of Relco, if the loco was in contact and other items were in parallel, say lit coaches, then the device will not fire up, and with a DCC system with more than one running at a time the same must occur.

 

My own set-up rarely runs two at once, so the unit does work, but a big layout will damp the operation, and in theory the unit never functions at all.

 

If it all is working, then Relco simply sits there doing absolutely nothing at all, all the time, simple as that!!!!

 

But the logic of this seems at first glance very perverse, if it does nothing then why have it? but it's the point of the device to make things run, and if running, then the track is OK, and the device is out of action. The same applies to DCC, if it is running, then all is well.

 

The only way to guarantee with DCC some cleaning action, would be to run one loco and nothing else for a cleaning session on a large layout, or use the towed cleaner B unit.

 

This is why the makers in the US offer the vehicle based unit, a better idea with DCC and DC all round, but it is US outline and big, too big for an 00 layout.

 

As I said before,on a big well used layout tarnish is not a problem, just awipe over will keep clean, but on small end to end, or small scale like N , it can pay to use the devices. I would never bother on O gauge, the weight guarantees contact.

 

My own reason for researching these and using them is for trams with overhead contact and it works very well here, as it does with any overhead system on DC. it would work with DCC, but with multiple feds may well be masked of and never come to life. My own choice with DCC and over head, would be a feed to the over head being isolated from the track power anyway, perhaps even using DC feed to the track for coach lighting, with a shared return for the separate signals.

 

And by the way, the HF devices do not add spikes of hundreds of volts, about 25vac to 30vac HF is applied during the operation of a single cycle, that's the RMS value approx., of the spike, it can exceed that voltage for a while on each cycle, but it will be a low average. It is not a zap of high voltage!

 

Stephen.

[bertiedog]

I should add that practical examination of wheels showed that even when several trams ran at once there was still cleaning, and I made up a DC test train with lighting to see what actually happened with more conventional set-ups, and even with the load of the lamps on it, the Relco operated whenever the motor lost contact, as there is a sudden change of load which triggers the HF in most situations. This would be especially true with today's low ampage LED lights, they draw low current , the motor high and the contact loss to the motor triggers the signal, which would be damped by the lighting somewhat.

What happens with dozens of locos on a large DCC layout is pretty obvious, nothing at all!!

 

So triggering may well occur in practice on DCC even with several locos, I do not know how the US designers have allowed for this in the commercial unit.

 

The proof of the pudding is in the eating, and with multiple DC tram set-ups cleaning still occurred, the usual proof was clean blackened brass wheels losing the blacking on the contact area. The Trams used Jackson brass wheels, and without the Relco wore to brass., but with Relco developed a matt sheen on the tyre, always clean.

 

The same applied to 00 wheels like brass Hamblings, whick were blacked, and wore in the same characteristic way that Relco induces, a matt sheen on the surface with extended running.

 

Stephen.

[bertiedog]

Stephen, with all due respect, but those 'one-of-a-kind' tests are IMO not representative for the purpose you've intended to show. DCC tracks are much cleaner in the first place, as decoders suppress the BEMF spikes, and safer cleaning can be obtained by using a cleaner car. That way you can be sure your decoders will not suffer from any damage a RELCO style unit may or may not bring.

 

Maybe to not confuse the average user, perhaps I have over simplified too much in the replies, but........

 

Hardly one of a kind as I sold units based on these circuits some 35 years or more ago, and the design was very, very, closely looked into, I am a qualified electrical engineer, and proper research and design was always done.

 

BEMF suppression does not affect the HF signal, different frequencies, and back EMF does not clean, or dirty, or influence the track tarnish in anyway, it's too low a level to break tarnish, which starts at about 25/30 volts.

 

Our model motors do not generate such large signals, the BEMF suppression is to ease the reading of the digital signals, and help prevent spurious pulses being interpreted by a DCC decoder.

 

Please note, track tarnish, this is all Relco or equivalent, will remove, NOT DIRT, OIL, OR MESS OF ANY TYPE.

 

This is the most deeply miss-understood aspect of these cleaners, they do not clean track!!!!!!!!!! They keep cleaned wheels cleaner, with a satin matt finish usually, that stays clean with no tarnish or oxide build up.

 

If all you run is nickelchromed wheeled Chinese models, then Relco would not have much to do, chrome does not tarnish in the same way. but most modellers have a mixture of makes and wheel finshes and most respond to the HF cleaning, as does most nickel silver track.

 

Steel track is different, the HF signal appears to induce some corrosion as the device is used, due to the iron oxide flaking more on removal, and steel track can become a bit rough in use with these devices in the very long term.

I did say very clearly the separate cleaning car offered would be safer, but this does not imply the direct use is unsafe, it is all relative.

 

When a DC model train proceeds down the track, although it seems to proceed smoothly, without lose of contact, or any visible effect, try putting a scope on the circuit and see what is happening, it is a constantly dynamic situation, with the current going up and down rhythmically with the motor rotation, and minute, and constant spikes and jumps and jitters in current occurring, plus BEMF effects, sending the voltage up and down from the applied voltage.

 

Even in this "perfect" situation the Relco does actually fire up, a few cycles, occasionally, an effect that can only be observed with a digital tracking scope, and is completely invisible to the naked eye, so to speak..micro breaks occur all the time and may last long enough to trigger the Relco.

 

I have also checked the exact situation on DCC, both a new home made unit and an NMRA approved design, and the digital signal is so much larger, than these effects, it does seem to suppress the Relco firing up, but it is there intermittently if you look hard enough.

 

It comes on during the spaces in the DCC signal, if there is a poor contact at that point, it is operatng at the signal speed, a dynamic situation, again observable only on a digital scope, I have an older PC devoted to digital grab display, and recording voltage and current tracking. the trace shows no operation at zero cross point of the signal, obviously no current is flowing then, but the HF comes in during the rise and especially the fall of the digital pulses, but again only if the signal fails to get through, all of this is happening so fast it is unobservable except on digital grab.

 

A lot of the time Relco does nothing, due to the good contact, but every so often it does operate, and as practical observation of the wheels show it is keeping the wheels cleaner than without.

 

None of this is a comment on others comments, just notes to outline the use and help outline the operation and possible pitfalls of these devices.

 

My personal position is that DCC has a poor record on the issue of track cleaning and running quality, if the signal had been raised to 40 volts, and the pulses applied, the cleaning action would be automatic, and tarnish would be broken naturally, but the German designers at Lenz, when they took the early Zero One design and other development work, adopted the lower voltages, due to chip limitations, and the computer practices of using low voltage as far as possible, and we have to live with a simplified Digital Control System based on commercial priorities rather than electronic excellence.

 

The US designers in the 1960's, who pioneered the use of what was to become DCC, made the use of a high standing AC voltage a cornerstone of the idea, with track tarnish cleaning in mind, but it all got forgotten when the industry got around to being able to make the Digital ideas practical.

 

Hope the notes make it clearer, the waters are already muddied about Relco, let alone adding DCC to it!!!

 

Stephen.

[Etched Pixels]

Steel track is different, the HF signal appears to induce some corrosion as the device is used, due to the iron oxide flaking more on removal, and steel track can become a bit rough in use with these devices in the very long term

 

It would. Rusting is an electrochemical process (which is why you use sacrificial anodes on steel boat hulls and water heaters and the like). Unfortunate for us modellers really.

[tractor_37260]

Since changing over to DCC control in the last few years, I've found the need to clean track/wheels etc very much reduced, once cleaned, they appear to stay clean much longer than when using DC even WITH HF cleaners. The then commonly used "rubber traction tyres" were I believe, partly to blame !

[Pete the Elaner]

Since changing over to DCC control in the last few years, I've found the need to clean track/wheels etc very much reduced, once cleaned, they appear to stay clean much longer than when using DC even WITH HF cleaners. The then commonly used "rubber traction tyres" were I believe, partly to blame !

Good reason for that:

 

HF cleaners use a high-frequency signal to keep the track clean.

DCC systems use a high-frequency signal to talk to decoders.

 

Anyone see a similarity here?

 

DCC also uses full voltage all of the time, so the age old DC problem of trying to make a small voltage push current across a poor connection (rail to wheel) is eliminated completely since this is always max voltage.

 

I therefore question the need for an HF track cleaner with DCC.

[hollywoodfoundry]

This might be a little OT, but in the same vein. There has been some interesting discussion going on among US traction modellers on the Yahoo groups, regarding the use of a graphite solution. The particular product called 'Lock-Ease' consists of finely ground graphite suspended in a volatile liquid. The liquid is applied with a cotton bud to the track and overhead wire and spread around by running trams on the layout. Once the volatile liquid has evaporated, the graphite is left as a very light coating on both track and wire.

 

Graphite, being a good electrical conductor, improves the contact between the tram pole/pantograph and the wire, as it does for the track. One would have to use it very sparingly on the track, as it is also an excellent lubricator, the prime use for the product.

 

But the East Penn Traction Club has been conducting experiments with this material for some time now and they report that it works surprisingly well. They have not had to clean track for a long time while using it and report much improved running of the models.

[Crosland]

Good reason for that:

 

HF cleaners use a high-frequency signal to keep the track clean.

DCC systems use a high-frequency signal to talk to decoders.

 

Anyone see a similarity here?

No, they are very different in all respects (voltage, current, frequency). The fact that DCC is AC has nothing to do with track cleanliness (or not).

 

DCC also uses full voltage all of the time, so the age old DC problem of trying to make a small voltage push current across a poor connection (rail to wheel) is eliminated completely since this is always max voltage.

That's far more relevant.

 

Decoder features can also help. Zimo decoders, with the capacitor backup supply, can be set to only stop on a section of track where there is good reception. A slow moving DC loco can stop on dirty track and then cannot be started without the hand of god.

 

Andrew Crosland

[Pete the Elaner]

The fact that DCC is AC has nothing to do with track cleanliness (or not).

 

Are you sure?

 

Why does applying a high-frequency clean the track? The only reason I could think of is that a varying current would create a varying magnetic field which scrambles some of the dirt. It shouldn't actually even have to be AC, although that would be better because it reverses the field.

 

DCC produces an alternating voltage: (virtually) a square wave. Square waves make the current change very rapidly albeit slightly out of phase due to the inductance & capacitance of the load (decoders).

[Gordon H]

Are you sure?

 

Why does applying a high-frequency clean the track?

It's more to do with high voltage than high frequency as the extra voltage the 'Relco' generates is supposed to break through whatever isolating medium is in the way. Excessively high voltages are what DCC decoders don't like.

[Crosland]

Are you sure?

Yes:-)

 

Why does applying a high-frequency clean the track? The only reason I could think of is that a varying current would create a varying magnetic field which scrambles some of the dirt. It shouldn't actually even have to be AC, although that would be better because it reverses the field.

A relco gives out a high frequency, high voltage limited to a very low current when the normal DC is interrupted by dirt. The idea is that the high voltage breaks down the dirt, or ionises the air, or something like that, and allows the DC to flow again.

 

Andrew Crosland