ConCor/Kato SW1200/1500 Chassis Power Pickup

[victor miranda]

backwards....
hmmmmm

this may seem a little odd,
is the truck rolling to the the direction or is the motor/frame moving back?

I would not think it makes much difference but it might explain what leverages what

It has to be the worm is lifting the body up off the trucks.
something is powering the wedge effect.

to fix that requires springs/wires to maintain conductivity,

[tehachapifan]

What happens on a change of direction is the trucks start moving in the new direction of travel first, then the chassis. It is during this transition/truck shift that the stall occurs. Or "was occurring" as I had a huge improvement today. I went out and got some Tungsten putty (man, that stuff is expensive!) and filled the fuel tank with it as per Ron Bearden's recommendation to add more weight. I had actually removed the stock cab weight during the kitbash and much prefer a see-thru cab anyway. It would appear that this was a big part of the problem and, after adding the putty, I had only one stall out of several changes of direction and at my slowest speed setting. The fuel tank...well, the clip on box behind the fuel tank detail on the stock model...is a great empty place to add weight. I made sure that the putty did not contact the frame halves to cause a short, assuming Tungsten putty is conductive. I'm assuming that the added weight is keeping downward pressure on electrical contacts and is minimizing the cause of the stall.

[victor miranda]

... weight....

yup that will work.

you may want to look into pure tungsten welding rods
I use the 1/16 size rod.

you can drill holes or stack it in with the putty.

[tehachapifan]

Well, spent the past few nights continuing to tweak and adjust this loco. The added weight did the trick for one night and then the problem started creeping back the next day. Ended up redoing the scratchbuilt spring contact strips on the rear truck and this helped tremendously. Was finally able to achieve near-perfect ops for the past couple days with no pickup problems at all and at very slow speeds. Since all the parts were cleaned and there was no lube on anything at all, I decided to try to add a miniscule amount of a common loco lube to the axle bearings to reduce wear. I applied an almost immeasurable amount by putting an ultra-tiny drop on an ultra-tiny wire and then placed it in the axle bearings. BIG MISTAKE!! The loco again has terrible pickup at slow speeds and I will probably need to tear it back apart and clean out all the lube once again. This is now the 3rd time this happened on this loco....think I finally learned this lesson.

[u18b]

You may have answered this on an earlier page..... sorry if I missed it....

But is there any reason why you seem so dedicated to this loco?

I have had a couple.  Got them to run pretty well.   But I have sold almost every single loco that is not running on a low friction modern mechanism.

The Walthers SW1200 is so much superior.

[victor miranda]

not speaking for russ,
I will take such projects to learn how to effectivly
repair or sort out such problems.

and at this point he has a beauty of an opportunity.
he knows the bearing are clean and that is the trick to good operations.

... now to find a lubricant that conducts.

[tehachapifan]

You may have answered this on an earlier page..... sorry if I missed it....

But is there any reason why you seem so dedicated to this loco?

I have had a couple.  Got them to run pretty well.   But I have sold almost every single loco that is not running on a low friction modern mechanism.

The Walthers SW1200 is so much superior.

The reason for all the fuss is this is the only mechanism I'm aware of that, once modified, could ride under my SW1500 bash (shown here after decoder installation with front and rear headlights and front gyralight installed and enabled)....



I looked very hard at trying to use the SW1200 drive but determined there's really no way it could be done. I believe the same holds true for the Kato NW2 drive.

not speaking for russ,
I will take such projects to learn how to effectivly
repair or sort out such problems.

and at this point he has a beauty of an opportunity.
he knows the bearing are clean and that is the trick to good operations.

... now to find a lubricant that conducts.

I'm the same way and love to tinker with things to try to make them better. However, this particular drive can be pretty frustrating in that it will run great one minute and poorly the next for no obvious reason. For example, it is running pretty good again this AM after the trouble I described last night. It's not running as good as it was before the addition of the lube, but it's better. Like Victor mentioned, it appears a conductive lube is key for this drive, if a lube is to be used at all. It would also need to not migrate very much because I suppose a conductive lube might be able to bridge across the plastic gears and cause a short.

[victor miranda]

the lubrication migrates that much?

I strongly recommend one of the graphite lubrications.
greasum or dry lock lubricant from the hardware store
at the least you can see if the graphite will conduct.
Max says that neolube does not migrate.

again with the bulb grease...
I am running a test of neo lube and bulb grease mixed.
... it is an improvement over nothing on the bearing/pickup
it darkens the bulb grease so you can see it....

I am going to try more neolube in the mix to see if it gets conductive...
based on what I have seen it is conductive, just more resistance than I think we'd like.

the package is labeled BG-1 and is made by AGS

[tehachapifan]

Thanks, Victor! I appreciate all the help on this.

I don't know if a conductive lube would migrate that much but I suppose it would be a possibility, especially if too much was applied(?).

I think I will try dry graphite next, although someone cautioned against it earlier. Right now the loco is running pretty good again, so I'm going to see how it goes as-is before I tear everything apart and clean out the oil lube. It is still stalling every now and then at switches and at a mystery spot on the layout that no amount of cleaning seems to be helping. Part of the stalling problem can probably be attributed to there being no flywheels in this loco, so any brief loss in pickup results in an instant stall (no flywheel momentum to help move the loco beyond a slight trouble spot). My original change of direction stall isn't happening right now, so that's good!

[victor miranda]

mostly because it is what I have....

I added more dried neo-lube to the mix.
I will state it is more conductive
and it is possible to make a stiff paste.
the paste is not good on wipers it wipes off. It seems.

thicked to... a creamy grease seems about the best.
it is conductive and I would not expect it to
be more than contact enhancement lubrication.

fun stuff.

[peteski]

I am going to try more neolube in the mix to see if it gets conductive...
based on what I have seen it is conductive, just more resistance than I think we'd like.

You going to have to add a lot of graphite to make it conductive enough (not more than couple of ohms for the thickens of a layer needed in a bearing.

When we discussed conductive lubricants conducta lube was mentioned (along with a URL of their website).  That is a silver bearing grease which "really" conducts electricity in the sense that we need.

I also think that Russ is a bit too paranoid about the migration of conductive grease causing a short (after all, very little is needed in the bearing).  I'm also not 100% convinced that it will solve his problem.  I hope that I'm wrong.

[victor miranda]

Hi peteski,
I am not certain about a lot of the reasons for the results.

here is my thinking....

graphite by itself does a lot of what we want.
it can be a lubricant and it is electrically conductive.
the problem with it is that it will not stay in the bearing
or on the wiper.
and so I thought the bulb-grease would solve the 'stay' problem.

... it does...
and the amount of bulb grease to graphite seemed to be a problem.
a little and the stuff still acted like bulb grease (helpful and has limits)
too much graphite and it acts a lot like graphite alone.
it gets out of the way.

one can customize it, thicker for bearings and thiner for wipers

it is not expensive to make in any case.

some lube is required. here is one that seems good.

ETA: I suspect that adding graphite to any oil will get you some enhancement of electrical path
through a bearing.

[victor miranda]

I been awaiting this situation.

the test pickups are being pulled by a re-chassised atlas/rr pacific
with new motor...

it is doing some modest speed like 7 smph and using 50ma and 3.5v.

it will stall... sorta.  I just watched it do one of these;

it slowed way down and the current dropped to 4 ma.
and then it waffled everywhere inbetween for several seconds. then back up to speed.
I did not touch the throttle.

dirt on the rails?

there was always an electrical path, just more resistance than we'd like.

I think the graphite is the reason because I have not had such a result with bulb grease alone.

victor