Ashi Valkoinen

Okay, help me with PF train motors

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So I ran into a problem I couldn't solve on my own but reduced the possible error to the PF train motor.

I have three, differently colored, but in dimensions and structure identical Stadler FLIRT electric motor units built from LEGO bricks. All three of them are powered with SBrick, using three PF train motors under each train.

Here they are:

00_img_7261_sm.jpg

I noticed that the yellow-green one runs slower than the other two, the speed difference on the same level of SBrick slider is very noticable, and there is a speed level when the yellow stops, but the other two runs on multiple curves and points with no problems. 

For first I thought that it could be the failure of the oldest SBrick in my yellow train, but when I replaced it with a new one, nothing happened. I measured output voltage on the output reserved for train motors, but it was just fine, only 0,02V less than the actualy batteries had.

Than I replaced train motors, all three to brand new ones and the train became even slower. Than I replaced all PF extension wires between battery box and train motors, still runs slower.

I measured the weight of the train, but they are 3882 and 3814 grams, the difference is only 68 grams (the yellow-green is heavier)., this is no explanation for the speed difference. 

Than I put the new train motors under the red one and it became slow as well.

It is also noticable that a train with new motors is harder to push by hand than the train with older ones.

So, my question is, did TLC change something in the internal gearing and other properties of the LEGO train motor? Neither Bricklink, not Brickset knows about the difference (if there is any), and the PF train motors has no production year printed on them, just "(C) 2005 The LEGO Group" on the bottom and a four digit code at one end, like  XX JX, where XX is a two digit number, J seems constant (I checked 10 train motors), and the X after "J" seems increasing with time (my oldest motors have J0, J1 or J2, while newer ones have J4, J5, J6 underneath). The XX digit seems totally random.

So does anyone know about any change in the inside parts of the PF train motor and could you advise me a method to select the faster ones?

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Posted (edited)

I'd not suspect a change in internal gearing. Think this is resulting from different motors used inside. Seems the motor itself has less power the later on this motor is manufactured. Any chance of comparing just the motors without carriages? Something along the lines of this test done by Alex Nunes: https://www.youtube.com/watch?v=OuyOJaH3vGI ?

Edited by Capparezza

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Posted (edited)

I'm grasping at straws here, but is it all possible they aren't going slower, but they don't have enough grip?  Is it possible the o-rings on he new motors are more slippery than the older motors?

Maybe try swapping wheels and see if that makes and difference.

--Tony

 

EDIT: I reread the original post and realized my answer doesn't really make much sense.  Sorry.  

Have you attempted to power the motors with a traditional IR receiver?  Do you still have the issues?  

Edited by SavaTheAggie

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Good point, but I bought motors only, without wheels, I replaced the wheels from old setup.

However the problem now seems solved, the motors with mark XX J0, XX J1, XX J2 seems to be faster while other ones (J3, J4, J5, J6, J7) are slower. I found some older motors and put under the green-yellow FLIRT (with same wheels), now it runs the same speed as the red and blue-white one.

Next week I will open up a new and older one to see what's the difference inside.

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Hm. I would've expected the older ones to go slower, due to wearout. It's a bit worrying that it is the other way around. This makes me ask myself another question: Are we getting less performance for the same charge with those newer motors? :sceptic:

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On Monday I will open up two of them, document it and also send my (and it seems your) rightful questions to TLC. 

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It would be interesting to see what the differences are.  Are they using fewer copper windings?  Weaker magnets?  Etc. 

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One thing that came to my mind was that if you drive an official Lego train set with the PF-Motor, the motor is indeed to fast and the train would derail in a curve if the motor was on full speed. Is it possible that this is a reason to intentionally make the motor slower?

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Is it possible that those which have had some running are faster, because they've been 'run in' and have a bit less friction?

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On 3/5/2018 at 2:35 AM, Stefaneris said:

One thing that came to my mind was that if you drive an official Lego train set with the PF-Motor, the motor is indeed to fast and the train would derail in a curve if the motor was on full speed. Is it possible that this is a reason to intentionally make the motor slower?

When it was suggested by train fan AFOLs that LEGO adjust the speed of the motors so they don't derail, the LEGO representatives explained that this was intentional as children like the possibility of crashes. It is considered a design feature.

 

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On 3/5/2018 at 10:34 PM, Paperballpark said:

Is it possible that those which have had some running are faster, because they've been 'run in' and have a bit less friction?

I don't think so, I have some motors of the newer series running under different trains of mine for months by now, but they didn't get any faster at this time.

Something had changed, and I had no chance this week to do the comparison by opening them up. :(

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On 3/1/2018 at 9:13 AM, Capparezza said:

I'd not suspect a change in internal gearing. Think this is resulting from different motors used inside. Seems the motor itself has less power the later on this motor is manufactured. Any chance of comparing just the motors without carriages? Something along the lines of this test done by Alex Nunes: https://www.youtube.com/watch?v=OuyOJaH3vGI ?

I agree, it's probably a difference in the motors. TLG doesn't care if one motor is slightly faster or slower than another motor as they don't make any trains that use two train motors. It's only a problem for us train fans who MOC their own. 

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