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GiantRoboJustin

Brand new Tomix DF200 motor (0624) problem?

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GiantRoboJustin

I think the brand new replacement motor for my DF200 might be bad already...

 

I purchased it because the locomotive was jerking and stalling randomly on clean track that all my other locomotives were having no trouble at all on, and I had ruled out all other possible causes (dirty wheels/contacts, mechanical binding, etc…)

 

Anyways, I ordered the motor from Hobbysearch, and after installation, the locomotive ran like new…for about 2 minutes, then it picked up the same problems where the old motor had left them off…and then proceeded to make them worse.

 

So, thinking I had just put a new motor in for no reason, I checked and double checked everything else again:

 

Trucks had no binding (in fact, they’re probably the smoothest rolling ones I’ve ever seen. I should also note I replaced the axles that had traction tires

with new tire-less ones for better electrical pickup. I have no need for them because I don’t pull long trains, or have any gradients on my small layout)

 

Worm gears and drive shafts seem to be in perfect shape as well.

 

Then I got an idea from another problem. A few days before, I was running my Tomix EF66 and noticed it was stalling for a split second whenever it went over my single crossover. So I ran it over very slow, and it stalled completely. Not only that, but the tail lights on the last car wouldn’t light up either. What was happening, was this:

 

http://my-miniature-worlds.blogspot.com/2015/04/kato-turnout-4-short-circuit.html

 

So basically the wheel contacting the two rails at once was shorting out the whole track, causing even the rear lights to stay out. This got me thinking, if something in the DF200 is shorting out, then other things on the track will stall or dim as well.

 

So, to check for this, I removed the motor, driveshafts, and worm gears so the unit would be a free rolling dummy with working headlights, hitched it up to one of my DE10’s, and towed it around every inch of my layout multiple times to see if the lights would flicker or dim. And they flickerlessly burned bright over every millimeter of it, even over the #4 crossovers, so no problems there.

 

Then, I put the motor back into it, but not the driveshafts or worm gears, so it was still a free rolling dummy, and then pulled it around the layout with the same DE10. But this time, there was a problem. Not only did the DF200’s motor hesitate and stall, but when it did, the DE10’s would as well, just as the tail lights did with my EF66 on the crossover. So it would seem that something in the motor is shorting out. 

 

So, I got a bad motor, right? Has this happened to anyone else? I mean, I know it sounds improbable that the new part would be bad as well, but then again, the last time I tried to replace the alternator in my car, I had to buy 3 or 4 before I got a proper working one. Is there something in these motors that can internally short out? I found a motor on plazajapan for $13, but wanted to get some second opinions before ordering…again, lol. So any ideas or advise would be helpful, thanks!

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kvp

I would advise you to check with a multimeter. There is the remote possibility of a commutator short, but another likely possibility is a body short due to parts contacting each other that normally should not. A commutator short is measurable as a short across the motor brush terminals while hand turning the freestanding motor. A body short is usually just an assembly mistake but hard to spot due to that many times only the running vibration brings it up. Also a good freestanding motor should turn freely even at low speeds when fed directly from a DC controller by two wires touching the two terminals.

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GiantRoboJustin

Thanks, I'll give that a go! I suppose if a flywheel manages to touch both halves of the frame at the same time that could short it out as well, I'll double check the clearance on that too and make sure the motor mount is fitting properly.

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GiantRoboJustin

Pulled the motor out today. Couldn't find any measurable anomalies turning it by hand except for one point where it did bind up when switching direction, So I hooked the motor itself to the controller and it ran like crap. Not at first, but it seems like the warmer it got, the more it would hesitate and sputter. The weird bit is that sometimes it would run at a low but steady speed no matter how much I crank up or turn down the throttle. Then after about 10 seconds or so, it would suddenly speed up as if it had broken free of something. But then a few seconds later be back down into the low speed again. So at this point, I'm pretty sure the motor is the most likely culprit. Can't get a new one for a while though cause I'm moving soon and don't want anything coming in the post until that's all done. But when I do, hopefully I'll have better luck with ebay than I do the auto parts store, lol

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GiantRoboJustin

Ah, finally got new motor last week! (was a bit nervous because my new address seems to confuse the post office a bit). Anyways, put the new motor in, made doubly sure all wheels, pickups, and gears were squeaky clean, and off it went like new! I also think I found out what happened to the last two motors (or at least the first one. I still think the second motor was just a dud out of the box). A few weeks ago I took my EF66 apart to maintenance and finally apply details and number plates, and found that the grease I had put on the worm gears last spring had degraded into something that felt more like melted gummy candy. I had noticed the locomotive getting much slower lately (which was the main reason for disassembly), and had even begun stalling after a few minutes of use (which I had blamed on dirty track, which turned out not to be the case). Anyways, I think this stuff was gumming up enough to start straining the motor and possibly overheating the brushes a bit, and after enough of this, the brushes might become toast. And just before the DF200 went down, I had run it for a few hours straight pulling at least 15 cars. And when I took it apart initially, the worm gears were all dirty and sticky, though not quite as bad as the EF66's.

 

I should also note, the grease I used was Aero-Car Hobby Lubricants NG JEL Gear Lubricant ACT-1111

 

I'm not 100% sure it was the grease that did it, but I doubt I will be using it anymore either way. It was incredibly difficult to clean off once dirty, even with a bath of 91% Isopropyl alcohol. So instead, I've gone back to a drop of Labelle 102 in each bearing and worm gear of each Tomix, and only KATO 24-021 for the gears in the Katos  

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kvp

Afaik Tamiya servo grease or Hilti power tool greese tends to work nicely and for me are easy to get locally, especially the Tamiya in the nearest shopping mall RC shop. Both seem to be synthetic and should not gum up at all, not even when dusty.

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cteno4

I’ve found that the thickest labelle’s oil has worked well for me on gears. Does not gum up but stays well coated in plastic gears. Only mechs I’ve needed to go to a grease are the funky tomix drives that use the metal coil/spring for a drive shaft and worm gear.

 

some greases don’t like some oils as well so if you pack the grease in the worm gear and later add some oil to the truck gears they gum up once mixed.

 

glad you discovered the issue before you burned out the motor!

 

cheers,

 

jeff

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Khaul

One of my Kato trains only wants to start when a rather high voltage is applied. Then I can slow it down and runs well. I am thinking about applying some grease to the worm gear. The Tamiya grease sounds good, and I can maybe get it locally. @kvp which grease do you mean in particular? Is it the Tamiya Cera-Grease HG?

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railsquid
8 minutes ago, Khaul said:

@kvp Is it the Tamiya Cera-Grease HG?

 

That's the one recommended in Japan, which seems perfectly fine.

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Khaul
1 minute ago, railsquid said:

 

That's the one recommended in Japan, which seems perfectly fine.

Excellent! Is it recommended for both Kato and Tomix? It would be nice to have one for all.

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railsquid

Any brand, I guess.

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GiantRoboJustin

For lube I just use a drop of Labelle 102 for my Tomix worm gears and bearings now, and nothing directly on the gears so as to help prevent gunk buildup. Seems to work great so far :)

 

I also have a Kato DE10 that has that start up issue as well. Makes it not so great for switching, lol. I put a drop of Kato uni-clean oil on each gear, but no improvement. I'm thinking something might be binding up, or maybe it's just not "run in" enough yet? I haven't messed with it much yet, but should probably see what's going on with it...

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cteno4

I usually use the 108 fine on the motor bearings as they are so tiny on most n scale motors. 

 

cheers

 

jeff

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GiantRoboJustin

Welp, looks like I just lost motor #3...

 

Got it out to run today after scoring an additional koki107 on ebay for only $6 (that's with shipping, so basically free 😄) and it suddenly slowed to a crawl, then sped back up, then started randomly stopping and starting every 2 or 3 seconds like it did with the motors before.

 

took it apart and bench tested it (still in frame) and it behaved erratically just as it did on the track. Then removed motor and tested it by itself, and same thing. It sounds kinda bad too, like something's come loose inside of it.

 

Anyways I don't think I want to test my luck, or another fifteen of my dollars plus shipping for a fourth one...

 

I wonder if there's a way to fit a different type/brand of motor in there?

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cteno4

Justin,

 

This is sounding like there is something else going on here. Have you had any issues with any other locos? Do you have another df200 and does it run fine? If not other problems and and especially if you have another df200 working well then it’s something else in the problem unit causing this I think a rash of that bad of motors would have been reported here by now. I know we have like 4 or so red bears in the club here (I have one) and no reports of issues here.
 

how where the gears? Mucky at all? I am wondering if that first grease you used is still causing bindings and burning out the motors. I’ve yet to burn out a motor, but I’m usually good at cleaning them out well at the first sign of stuttering that’s not related to track dirt. Only burned out motors I’ve had to deal with in the club was the old Tomix spring worm drive that can get very tight when grease gets old or all moved out of the gear box eventually. But those spring worm drives are horrid compared to a standard worm gear.

 

something is really wrong if it’s eaten three motors and I would suspect the mech now more than bad motors.

 

Jeff

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katoftw

if it has burnt out multiple motors, then it is an electrical issue.  either the light board has something wrong with it or the metal plates of the chassis is somehow touching something and shorting out the motor.

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GiantRoboJustin

Thanks for the responses!

 

I have a Tomix EF66 and DE10 and haven't had any problems with them even thought they get far more use. I think the EF66 even has the same motor, just different flywheels.

 

I've checked the trucks and worm gears and everything is clean and rolls freely

 

I couldn't rule out the light boards as a problem, so I went ahead and removed them and then tried running it.

 

It ran for 7 minutes with no problems, but then once I had just about considered the problem solved, it abruptly came to a crawl, then would jackrabbit start, then back to a crawl over and over until I turned the throttle off. I took the motor out again and attached leads directly to the contacts on the motor, and it behaved the same way. Randomly alternating between fast and slow.

 

The thing that really puzzles me is that I feel like most of the time I hear about these motors burning out they just stop all together and trip the circuit breaker on the controller. Mine keep running, but just become erratic, almost like the problem is in the controller, but it runs other trains just fine, so it shouldn't be that.

 

I wonder if it could be excess carbon buildup? I think I used this motor a bit before I discovered the gunked up grease in the worm gears, so maybe it got overworked then, and this last bit of running was the straw on the camel's back

 

If so, I wonder if an ultrasonic alcohol bath could do the trick. I saw a youtube video where they did it to a dead tomix motor and it worked. I'd have to get an ultrasonic cleaner first though

 

Might be worth a shot as all these motors seem to be sold out at the moment...and it may come in handy for other stuff too

 

 

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cteno4

Yeah maybe it just wore it out before totally cleaned out. 
 

worth a shot in an ultrasonic bath. A small one is like $25-40 and worth the investment in the long run as they are great for cleaning out trucks, gears, etc.

 

btw if you don’t want to fill the whole chamber with your cleaning fluid you can fill it with water and then float one of those little takeaway plastic cups in it with things like alcohol in them so you don’t have to use a whole bottle to fill the bath with it. It reduces the power you get to the part some but still does the job usually. I usually do whole chamber runs with soapy water then water rinse baths, then at the end just do the boat of isopropanol a couple of times to get all the water displaced. Then put the parts in a warm place for a while. If something like a motor that can trap a lot shake it out the best possible and will use an old taster oven I have at the lowest setting with the door open. Gets up to like 110F and helps everything evaporate well.

 

jeff

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