Shortcircuits of TOMIX Type 126 Shinkansen motor module

[AhmadKane]

Ive been spending a good 3 hours on this now.

 

Ive received a tomix 100 series shinkansen starter set with no controller. I tested the motor cab and it didnt get any power. I took out most of the parts and slowly digging to the motor, whilst testing bit by bit. I find the mechanism similar with other tomix shinkansens such as the 500 series

 

The motor works fine, so I lubricated the worm gears and the axles. Placed it back until the interior plate and found it to be alright. I then placed the motor bogies till the shell. 

 

It ran, but only for a couple of seconds before turning off. Apparently it shortcircuited with the main body.

 

So I repeated the steps. Jumped the motor directly. Its fine, placed the interior. Jumped the interior slots for a good minute, its fine. Placed the bogies and jumped the wheels, its fine. Placed it on the track, shorted after 15 seconds of running. Jumped it, didnt move. 

 

 

Took the bogies out again, and it moved. My guess is that the entire module shorted from either two locations. Between the interior plate and the iron weight, and the bogie springs with the iron weight. Either one would graze the iron weight and shorted the entire motor train.

 

Could anyone give me some advice? My thought would be to seal off the conductive plate and the iron weight with tape as an insulator. And the iron wall surrounding the bogie coils would also be insulated with tape. 

 

Also, i see theres a capacitor fitted. What are those for? Could they cause the problem as well? Ive taken it out but the problem still persisted, so it isnt that.

 

 

[AhmadKane]

Update.

 

Ive tested it a bit more, and I have a sneaking suspicion that this is not only due to shortcircuit, theres also a possibility that this is due to overheating.

 

Which is baffling because arent these modules supposed to cope with long amounts of playtime? I dont recall tomix being this poor. I feel that the body is a bit warm after it stopped, and a small jolt after 5s would have the train moving again, before it stopped again

[Martijn Meerts]

I've never had a Tomix motor get so hot that it's caused issues, apart from the Tomix cleaning car motor running at full speed on a DCC layout 🙂

 

It does sound like it might be a short. Does your controller have short protection? If it does, it might turn off power after a short, and turn it back on after x seconds, which makes the train move again for a bit until a short is detected.

 

It's really hard to troubleshoot these kinda things without having access to the model in question really. It might very well be a spring is ever so slightly misaligned which causes the short only to happen with the bogie in a very specific position for example.

 

[AhmadKane]

Heres the video

 

https://youtu.be/lqILvkgLJ50

[AhmadKane]

I think its a shortcircuit afterall. Coming from the motor bogies. The tomix controller did do a shortcircuit protection thing.

 

I am fully confident that it isnt the interiot plates. Perhaps I have to realign the coils? Or try to insulate the iron walls of the bogies

Edited January 13, 2021 by AhmadKane

[AhmadKane]

After borrowing the multitester. I concluded that the main problem is the motor. Electricity has escaped causing the shorts. 

 

Ive transplanted a motor from a Ltd Express to the shinkansen, switched the axle sleeves. It now runs brilliantly.

 

The next question would be to find similar motors, ones that could be transplanted unto the limited express. Anyone tried using alternative motors? Tamiya are a bit too large

[Yavianice]

Have you checked Tomix Tec Station for replacement motors?

[Martijn Meerts]

Tomix has a good selection of replacement motors, and many of them are in stock in various places. They're also not really that expensive.

 

That said, they are fairly standard motors, so it might be possible to find a fitting non-Tomix replacement.

[AhmadKane]

Im looking for the non tomix alternative first. Since buying tomix meaning imports, if I could get one without importing , thatll be grand.

 

Anyone tried a non tomix alternative before? What did you guys use?

[Martijn Meerts]

I've only even changed 4 motors, 3 in European trains, and 1 Japanese one, but I've always used official spare parts. In all those cases though, the motors came with flywheels attached, and those can be difficult to attach yourself. They need to be near perfectly straight, otherwise your train will start acting strange.

 

[cteno4]

I’ve only replaced a couple of Japanese motors for clubmembers and used the correct replacements. Usually pretty inexpensive (but more for shipping now I’m sure) and drop in. I’ve tried to source small electric motors for more general projects in the past and it’s usually been a hassle of finding proper dimensions, rpm range, power, voltage, etc and I’ve wound up buying a few to eventually find the correct one. I’d say it’s not worth the time and effort in sourcing an alternate replacement for Japanese trains as most are in pretty tight frames and dimensions. Folks repower all the time in HO as there is gobs of space to play with and easy to change gearing and such. Not impossible just could be a lot of work to find matching motors. All depends on what you want to spend your time and money on.

 

jeff

[AhmadKane]

I see... Very well, I'll fork in a bit more for the original one Might as well buy some assy parts too. 

 

 

[inobu]

take the motor apart and see what it shorting.

[cteno4]

The main part I’ve had break (and in the club as well) has been the plastic driveshafts. These usually strip on the little nubs on the ends for the universal socket joint (did have one snap in two). I think usually from an abrupt stop maybe, never know for sure, but probably replaced maybe 10 in the last 20 years (mostly clubmembers). it’s almost always been Shinkansens which may be due to higher speeds driving a lot of cars and crashes usually are pretty brutal stops. Also at shows the shinkansens can also get run for long times at high speeds so I’m sure a bit warm in there. But all and all pretty rare to have breakdowns, usually just the usual wheel cleaning, degunk and lube stuff.
 

Luckily they are one of the cheapest parts so over the years I’ve just ordered one or two with HS orders and have a good smattering of them now and can usually find ones that will work. Tomix even had an adjustable one! Most may sit there forever but it’s nice to now have a dozen or so sizes there if needed.

 

jeff

[cteno4]

3 minutes ago, inobu said:

take the motor apart and see what it shorting.

always a good idea to do a necropsy! You always learn stuff as well even if it’s just practice figuring out how things go together!

 

jeff