L Motor Freezes

[yoshi98bc]

Im attempting to put 2 L motors in a SD70 model. They are placed horizontal with a 20T gear on the motor. There is another 20T gear in the bogie. Ive tried the setup with a sbrick and a V1 receiver. The motors seem to freeze after a very short period of use. Wondering what could be causing this?

 

Anyone else encounter these issues?

[ALCO]

Not sure on the cause, but I've got a Big Boy articulated steam engine with 2 XL motors using the same gearing as the Emerald Night. I would probably start with trouble shooting one of the trucks first. Make sure all the wheels and gears run smoothly with hand power. Then do the same with the other. Once you are sure everything is turning smoothly, add one motor, then the other. I had to make sure all the axles were secured near the gears because they would lift off the gears. Also more of an XL motor issue because they have more torque.

Another thing to check is the passage of the axle through the king-pin because that can cause a lot of friction too. In my Big Boy I use 4x4 turntables with the axle hole in the middle so all the turning and lateral forces act on the studs and the turntable and not the drive axle. I have heard of people having issues with using the drive axle as the king pin so that is why I chose the turntables.

 

Based on what I have read about electrical loads and the receivers, I think (my opinion) you should be fine with a V1 receiver since you are using L motors. They don't draw enough current through the receiver to warrant a V2. But that is my understanding of what I have read. Everyone's application is different.

Hope that helps!

[jtlan]

Power functions trains usually require a certain amount of mechanical expertise and fiddling, so the problem may not originate electrically. Would you mind posting pictures of your design so I can assist in debugging?

One other thought -- disconnect the motors from the model and try running them. Do they still seize? What if you load them lightly (by grabbing the output shaft)? If so there may be an electrical issue; otherwise, I'm inclined to believe the problem lies in the design of the drivetrain.

[pirzyk]

Define freezing.  Does the motor make noise but does not rotate the shaft?  Is the motor housing hot? Check also the it receiver.  I wondering if something is overheating.

[yoshi98bc]

So i appreciate the replies and i will start the troubleshooting. 

I feel it is overheating but it could be because with my drivetrain causing overheating I will take photos in a few.

 

It will run fine for a while by itself. Then when i apply a load (rollling stock) it will just seize up and stop. Motors appear to buzz. When i stop it and restart it will start again for couple seconds. Its exactly what you see in this video.

https://www.google.com/url?sa=t&source=web&rct=j&url=%23&ved=0ahUKEwigmf3qz6_WAhUKQyYKHRSFBnkQxa8BCCYwAA&usg=AFQjCNF1sHlk2z9QIx28jtvfnGP_UlkifA

This happens not only with lego receiver but also an sbrick.

[yoshi98bc]

So i was able to do some testing. With only 1 motor attached it runs fine but is slow and weak with both sbrick and PF receiver. When a reattach 2 motors it freezes again. I removed the AAA battery box and replaced it with AA battery box it works fine. So i assume its the AAA battery box. I have tried multiple ones with same result.

[legoman666]

I've had issues with the axle into the motor being shoved in there too hard and causing the motor to stall/not work at all.

 

Both the AAA and the AA battery pack have a 800mA fuse, so there should be no difference as long as the batteries you're using are similar enough.

[yoshi98bc]

Just tested again. Freezes with aaa battery box. Works flawlessly with aa battery box. Hard to hide the aa battery box so this isnt good

[dr_spock]

Do you have another AAA battery box to try?  Sounds like the one you're using, its fusible link may be tripping too early.  The AA and AAA battery boxes should have the same resetable fuse value.   Maybe the expensive Rechargeable LiPo battery box of the same size could be another option.

 

[kieran]

I think all battery boxes have a resetable thermal fuse. The current draw of 2 l motors is most likely tripping this. If you are not a purest you could bias this fuse if you are happy with the risk

[zephyr1934]

I've never really used the AAA battery box, but I have used the LiPo battery a lot. I've had troubles with the IR receiver tripping its thermal resistor but never the battery box. This problem only occurs on my heaviest trains. I just always assumed the IR receiver was the weakest link and have not had troubles with the LiPo batteries after replacing the receiver with an SBrick on the heavy trains. Since you've already tried an SBrick, I too would suspect the battery box. If you have a second AAA box around definitely try that. Oh... wait... you tried that too.

Stupid question, but just in case, did you try fresh batteries? It is possible that an entire pack of batteries are bad or your lot of rechargeables are nearing the end of their lives. So try borrowing 6 new AAA batteries from a friend or neighbor.

The battery box should be able to pull a light locomotive with two L motors (I have a couple of trains with two XL motors and an IR receiver and no problems there).

The fact that the single motor runs slow and then dies indicates that some current is flowing. There was a problem with the AAA battery box not fitting all batteries well, you might be encountering that problem too. Search the train forum for AAA battery box and you should find a few threads on it.

Failing all of that, try calling Lego customer support. At the very least they should be able to tell you whether or not the AAA box is rated for two L motors, and if it is maybe they will deem yours defective and send out a free replacement.

[yoshi98bc]

Appreciate the responses.  So i tried another AAA battery box again and it seems to work. Maybe I have a couple bad AAA boxes so i will be testimg that next. Appreciate all the great advice 

[M_slug357]

Could the battery box problem possibly be a generational thing?

If I remember correctly, the L motor & Servo motor were released a while after the initial release of the Power Functions line... So if you have a AAA battery box that was made before L motors were introduced, it would make some sense that the box can't handle the newer elements.

I think?