Lubricating conductive bearings

[seigezapf]

I have replaced the sound card in an Aristocraft slope back tender. The original sound was faint and intermittent. So I put in an ITT slow-chuff board and hooked it up to the track leads and the speaker. I first checked the circuit with a battery and it worked fine. It does not, however, work when connected to track power. With a multimeter I found that the track pickups do not seem to be reliably conducting power. The tender has two pairs of wheels for track pickup. For each pair the pickup wires are directly connected to the bearings. I believe maybe if I lubricated the wheels with a conductive grease or oil the conduction might improve. I have read that Bachmann EZ-lube conductive lubricant might help. Do you have any suggestions that might help? Thanks.

Craig

 

[Greg Elmassian]

Most "conductive" greases are not conductive at all, like LGB conductive grease. They claim increase in conductivity because the grease keeps the air off the metal, which should retard oxidation which should improve conductvity.

There is real conductive grease, which is usually used with slow moving bearing surfaces or wipers, and they often have copper, nickel, or silver in them. Very expensive and you have to be careful it does not go where you don't want it.

The better solution is to make all axles pick up power. I'm guessing you have the carbon brush pickups that rub on the backside of the wheels.

Greg

 

[seigezapf]

Thanks Greg. The tender doesn't use sprung carbon brushes, though I have seen that used (on the Rogers 2-4-2). In this case the tender has two trucks each with two wheel sets. The rear wheel set in each truck has the pick up wires. The wires are soldered to tabs that are part of the brass wheel bearings -see photo..

 

[Greg Elmassian]

So in this case, I believe you are only picking up from the axle, so you only have one pickup wheel per axle. In this case, on my aristo, I made sure that I picked up on all 4 axles, but still that was only 4 wheels, not eight. If you are using a chuff switch, then putting on a large electrolytic capacitor in the circuit to store charge will probably fix your problem.

 

[seigezapf]

Thanks Greg. The pickups are on both wheels (one on each side) on two of the four axles - the rear axles on each truck - see photo.



Are you suggesting that I move the pickup bearings on one side of each truck to the axle that currently does not have a pickup? So one wheel on each of the four axles would have a pickup. I am not using a chuff switch. The sound board I had in mind was a simple slow chuff that plays continuously when powered. Actually I'll probably use a different sound board if I can get the track power pickup sorted (Mylocosound which adjusts chuff rate to input voltage without a chuff sensor).

Where in the circuit would I put a large electrolytic capacitor (and what values should I get)? Thanks again.

Craig

 

[Greg Elmassian]

I've never had a slopeback tender, and it appears that the axle halves are insulated from each other, so you have 4 wheel pickup now... if you could add the same setup to the other 2 axles, you would have 8 wheel pickup.

The closeup in the earlier post looked like the more modern system, sorry.

On the capacitor, I'd check with the sound card manufacturer to see if he has a recommendation first, as to capacity, voltage and where to connect... failing that I can explain an alternative method.

Greg

 

[PhilP]

As well as making all wheels collect power, it appears that the plating is worn through?
See if things improve by cleaning the tyre and flange on those wheels presently picking up power.

 

[ntpntpntp]

I have two of these tenders. To date they've not been any trouble apart from the plastic axle separators cracking. I replaced with plastic tube (the body of an old pen actually!). You do need to keep the wheels clean to ensure reliable pickup. I run mine on DCC with the original sound unmodified, they cope fine though you can hear the DCC "sing" a little.

 

[seigezapf]

Greg, I looked at a schematic of the slopeback tender and it showed wire contacts on the bearings of all 8 wheels. None of the photos I could find on the internet of the tender underside showed more than the 4 wheel contact mine has. I'm going to see if I can find a crimp terminal - or I may have to order something - that will work for the unattached 4 bearings and then wire them. Nick, do your tenders have wires going to all eight wheels?

PhilP the plating seems to be fairly good, but I did as you suggested. I polished the wheels and axles and sprayed the inside of the bearings with QD electrical cleaner. It helped.

Nick, I ran the tender before trying to modify it. The sound was very faint even with the volume knob all the way up. Maybe it would be OK indoors, but outside the sound almost disappeared. Also, the sound was intermittent. The board I hope to use (MyLocoSound) has much more volume.

I think I am getting closer. I'll see if I can double the contacts. I'll also make sure the wheels are clean and I will lube the axles with Bachmann EZ-lube conductive oil (that I have ordered). Hopefully . . .

Thanks all for your help.

 

[Rhinochugger]

I have replaced the sound card in an Aristocraft slope back tender. The original sound was faint and intermittent. So I put in an ITT slow-chuff board and hooked it up to the track leads and the speaker. I first checked the circuit with a battery and it worked fine. It does not, however, work when connected to track power. With a multimeter I found that the track pickups do not seem to be reliably conducting power. The tender has two pairs of wheels for track pickup. For each pair the pickup wires are directly connected to the bearings. I believe maybe if I lubricated the wheels with a conductive grease or oil the conduction might improve. I have read that Bachmann EZ-lube conductive lubricant might help. Do you have any suggestions that might help? Thanks.

Craig

I use Peco's electrolube (now called Pecolube I think) on bearings that are conductive - used sparingly it does help.

 

[Greg Elmassian]

Over time, Aristo cut back on wiring/cost/labor, and we found that the wiring to the tender was as you have found, only wire 2 axles not all 4.

A small "ring terminal" can be installed under the bearing by pulling the bearing out and putting the ring terminal "under" it. I found some uninsulated ring terminals and had to enlarge the hole a bit to clear the bushing diameter.

Greg

 

[ntpntpntp]

Just checked both of mine, and both have pickups on all 8 wheels. The oldest is 2nd hand un-boxed so I don't know its vintage, the other was bought new (sometime after 2009 I think) in a yellow Aristo box.

Here's a shot of one side of one the trucks on the oldest tender (you can see my repairs/replacements of the plastic axle stubs!) Just behind the chuff magnet is a 4 pin header I use to link loco and tender power.

 

[Rhinochugger]

I know it's wandering off piste, but I could never understand why none of the G scale manufacturers have gone for metal side frames with a plastic spreader. solves all of the problems in one.

Yeah, well, most of the problems..............

 

[Zerogee]

I know it's wandering off piste, but I could never understand why none of the G scale manufacturers have gone for metal side frames with a plastic spreader. solves all of the problems in one.

Yeah, well, most of the problems..............

Yes, that would make a lot of sense.... I'm trying to think of a good reason why not, and apart from the simple one of cost of metal vs. plastic I can't come up with anything right now.....

Jon.

 

[PhilP]

I know it's wandering off piste, but I could never understand why none of the G scale manufacturers have gone for metal side frames with a plastic spreader. solves all of the problems in one.

Yeah, well, most of the problems..............

Well, like most good ideas, it is blindingly obvious.. In hindsight!
My guess, is that the designers / engineers building these see it has 'always been done this way'..

 

[Greg Elmassian]

No, it's cost, pure and simple... always look to the bottom line in manufacturing. Aristo was not a high end line where people expected top quality, they expected low prices, and they got them.

Greg

 

[Rhinochugger]

No, it's cost, pure and simple... always look to the bottom line in manufacturing. Aristo was not a high end line where people expected top quality, they expected low prices, and they got them.

Greg

Agreed - but, I'd have thought that there could have been an offset in assembly costs - but then, if the overseas labour rate is nuppence per hour, then that'd be the saving................

 

[Greg Elmassian]

Yes, if they do not lubricate at all, that will save in assembly costs too!