running problems - kit build

[Sylvian Tennant]

Hello 

 

I am currently working on a Nucast G5 that was given to me by a friend. He there was a lot of work to do but I was more than happy to have a bash at. It looks to me like a live chassis system for pick ups and uses X04 motor. 

 

I've cleaned wheels up and they're free running.

 

I've cleaned the motor up and that works a treat.

 

When I connect the whole thing up I seem to have problems - sometimes it works okay, other times I doesn't, I've seen the motor start up okay and then gradually lose power, if I put the body on it 9 times out of 10 it struggles to start or not budge at all. 

 

But I take it apart and generally goes back to a fully working motor and free running chassis.

 

 

[34theletterbetweenB&D]

Sounds like a motor in good shape for electrical circuit, but with a weak magnet. So it spins freely with no load, but struggles and then fades when only modestly loaded. If you can pull the worm off and run it at 12V, the classic test is that it should require real effort to stall by pinching the motorshaft between finger and thumb.

[polybear]

 

 

But I take it apart and generally goes back to a fully working motor and free running chassis.

 

It could be that the body is distorting the chassis very slightly, causing binding etc.  Are the wheels etc. free to move when the motor is removed?

[Sylvian Tennant]

I've had it working with the body on a couple of times. Most of the time however it just stalls. You switch it in the direct it wants to go and you get the buzzing - then when you apply power the buzzing get's quieter. 

 

I have modified the chassis using brass components but it's no shorting - just refusing to budge. I will say this too - it works better going backwards than forwards currently too - it's sightly faster and generally works better in that direction. 

 

Hmm weak magnet - I'l give that a try tonight.

[Guy Rixon]

If it works in one direction and not the other, it may be that the gears bind.

 

If the worm shaft is only supported by the motor bearings (and assuming that the motor has no thrust bearings, small motors generally don't), then it will move along the worm axis under load. The mesh will be different for the two directions of travel. It's possible for it to change the mesh enough to jam the gears tooth-to-tooth and stall, and it may not do this every time. The effects would increase with the load on the motor, so adding the body weight might force it beyond its limits.

[jwealleans]

Nah, that's a rule of kitbuilding - whatever you build, it always runs better backwards.

 

The ideas you've had seem sensible - does it run better if you leave the body fixing screws slightly loose?

 

If the magnet in the X04 is weakening you can have them remagnetised - see your nearest Hornby Dublo enthusiast (one of the guys at Ormesby Hall has one) or if you have another motor/gearbox you can drop in and try that?

 

The motor isn't shifting and shorting or arcing to the body, is it? Try it in the dark, see whether you see any sparks.

[Kenton]

Slightly bent motor shaft. As so often with kit builds go back to basics and replace items. The range of potential causes is very large and could be any single one or combinations of them. Even those combinations could be difficult to isolate as they could be counter acting. For example a bent shaft could impact on a misaligned or um-centered/worn/eccentric gear, even causing intermittent shorting with chassis/body.

 

It sounds as if this works occasionally. On those occasions try running it in.

 

My vote is for a non-meshing gear, in my experience the usual cause of directional difference in running but what is causing that non-meshing the list is open.

[Simon Moore]

Drop kick the x04 down the nearest liftshaft & fit a decent gearbox for starters. I've had the same issue with a second hand flatrion I got with a triang chassis.

 

Failing that, put some form of isolation tape on the body where the motor sits & see if it's the motor shorting on the body. I personally would fit a mashima & highlevel box for the cost of about £35 it'll be a far superior drive system that'll give good running.

[Sylvian Tennant]

I've give a few of those a try - it is an old motor and set of gears so I'm putting my money on it being magnetising or a disjointed mesh but's just an educated guess. The loco body itself (as it's in a state of revitalisation) hasn't been screwed on and I've left the screws for the motor loose too to see if that was the cause but low and behold it's still the same.

 

I think once I've got the money I think it would be easier in the long run to rebuild the chassis using a High Level gear box and motor as one is doing impeccable work in my Q6. It's currently using (as mentioned) live chassis pick up which may have been nice at the time but seems very dated and has too many cons outweighing the pros IMOHO AND I prefer full wheel pickups. The only issue with the High Level products is that the chassis width clearance is only about 6.8mm. 

 

I have a J27 (scratch built I think) with the same problems but I've scrapped that chassis completely and I'm planning to modify a Bachmann Jinty chassis as a replacement.  

[Daddyman]

The only issue with the High Level products is that the chassis width clearance is only about 6.8mm. 

 

High Level do gearboxes down to 6.5mm in width. 

[Sylvian Tennant]

I think that's sorted it then - the motor finally packed in the other day so a high level gear box and Mashima motor it is. I'm going to forego the live chassis technique and have all wheels insulted. I've burred out the opening in the chassis so it should accommodate the small of the HL gear boxes.

 

So now the question begs where can I easily get some Romford wheels in both 21mm and 12mm diameter?

 

I've had a look online but can't really find much and I'd like to use as much of the original components as possible (axels and coupling rods) - hence why I've chosen Romford.

[Jim49]

." I'm going to forego the live chassis technique and have all wheels insulted."

 

How will you do that? Call them square?

 

 

Jim

[Sylvian Tennant]

Ahh jockstraps! sorry no forego! bypass

forget - not use - delete were applicable

[Sylvian Tennant]

Has anyone had any experience with Scale Link wheels ? they look more readily available that Markits(Romfords) and the largest ones (20mm) are the same size as the one previously employed on my G5.

[jwealleans]

Yes, I have. I think Tony Wright has used them occasionally as well. They're to the same pattern as Romford/Markits but with a plastic centre. Not quite as good - I had to ease the square hole to get them to go onto Romford axles and one set I had (seems only to be one size) was slightly narrow to gauge and had to be shimmed out but they run well.

 

I have a feeling TW said the loco he built with them seemed to have more 'grip' than when he fitted it with Markits. They only do a limited range of sizes, though, IIRC.

[Quarryscapes]

Has anyone had any experience with Scale Link wheels ? they look more readily available that Markits(Romfords) and the largest ones (20mm) are the same size as the one previously employed on my G5.

 

Yes they're fine enough wheels, the ones I have are nice and true. Beware the sizing though, they appear to be nominal only - for example the 18mms I bought are actually 18.5mm, no doubt intended for Pannier tanks, I dare say the 20mm ones could also turn out to be for  5'2" prototypes and not dead on 5'! 

[Sylvian Tennant]

Cheers for the heads up - truth be told that wouldn't be too bad for me as 5' 2" is closer to what I'd need than the 5' anyway - as long as they don't all vary between 4'6 and 6'8"! 

 

Okay I think scalelink sound like an option - in fact if I'm not mistaken I may have some for my Q6 tender (Though God know's how I bought them in the first place - it might have been Railex NE) and they are doing an alright job with the tender pick ups. Save the fact I almost melted the cutting off the pinpoints.