# Magnatraction



## johnfin (Nov 28, 2009)

Do the magnetic traction engines of the early 50's seem kinda slughish and not as smooth as the engines of today. I cleaned and oiled all points, new brushes in the motor, cleaned cummutatot yet the engine is not very smooth. Maybe I should not compare it to the newer stuff. It would be like comparing a '50 ford to a 2010 ford.


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## Boston&Maine (Dec 19, 2007)

I agree, older motors are definitely not as smooth as modern can motors, and they cannot move as slowly as modern can motors... One thing which makes the new motors more smooth is the balancer that each motor has (at least on my MTH locomotives)...


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## Big Ed (Jun 16, 2009)

Check the spring tension on the brushes. If they are weak or if they are to tight it will make a big difference in how the engine runs.
Try backing off on the brush plate screws just a bit and see if it runs better. If it does that's your problem.


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## Reckers (Oct 11, 2009)

Nice pointer, Ed. I'd never considered that one.


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## servoguy (Jul 10, 2010)

The 3 pole motors in the older locos have a torque ripple of 2x. The peak torque is double the minimum torque. This is why they don't run smoothly at low speed. The can motors have more poles on the armature and so are smoother. I will say again that I get better low speed running by oiling the commutator with 5W-20 engine oil. I know this sounds crazy, but it works great. I started doing this a year ago and have had no trouble with the oil getting gummy or burning.
Bruce Baker


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## Reckers (Oct 11, 2009)

servoguy said:


> The 3 pole motors in the older locos have a torque ripple of 2x. The peak torque is double the minimum torque. This is why they don't run smoothly at low speed. The can motors have more poles on the armature and so are smoother. I will say again that *I get better low speed running by oiling the commutator with 5W-20 engine oil*. I know this sounds crazy, but it works great. I started doing this a year ago and have had no trouble with the oil getting gummy or burning.
> Bruce Baker


Bruce, would that be in reference to the older ac motors, or the can motors? I have no problem with any suggestion that works, crazy or not.:thumbsup:


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## T-Man (May 16, 2008)

Len, the can motors are enclosed.


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## servoguy (Jul 10, 2010)

Since the can motors are enclosed, you can't get at the commutator and, based on performance, there is no need to do anything to the can motors. My comments apply only to the open motors, both post war and pre war.
Bruce Baker


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## Reckers (Oct 11, 2009)

Hmmm....long-time listener, first-time-caller, here. *L* So what you're both saying, in a very tactful and gentle way, is that only an idiot would have asked that question?


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## servoguy (Jul 10, 2010)

Nope. It is a good question because I am sure many others had the same question or will have the same question but didn't bother to ask. 
Bruce Baker


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## Reckers (Oct 11, 2009)

Bruce, your wisdom is only exceeded by your kindness, thank you. T-Man, thank you for concealing your laughter when you answered!


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## tjcruiser (Jan 10, 2010)

Very interesting ...

I would have never thought that the torque output was anything other than near constant. "Torque ripple of 2 x " ...

Hmmm ...

Thanks for another insightful lesson, Bruce!

TJ


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## servoguy (Jul 10, 2010)

A few months ago, I did a torque ripple calculation for some 3 phase brushless DC motors using Hall effect transducers for commutating the motor. This method of commutation for a brushless DC motor is equivalent to the brush commutation used on the Lionel motors. Anyway, from this analysis came the result that the torque ripple is 2x. If you run a loco slowly, you can hear the motor speed up and slow down. I think this torque ripple is probably what is causing the noise in the whistle motors. You get the same problem with torque ripple when you use a variable frequency drive to run a 3 phase induction motor. 
Bruce Baker


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## johnfin (Nov 28, 2009)

*Magnets*

What about the magnetic wheels, do they cause some type of drag?


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## Reckers (Oct 11, 2009)

Along the same line as Johnfin's question: for model railroading only, not the real thing: does a 6 drivewheel locomotive outpull a 4? It seems an argument of extra weight vs extra traction with the same electric motor. Anyone have any thoughts to offer?


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## T-Man (May 16, 2008)

Magnets help traction.
More drivewheels help traction
Still 25 words or less.

I never did reply to your comment, Len.

Also, we get plenty of AC DC motor questions. That's why I went to the 4 wheel drive motors to show the difference. You must be stressed from the layout work.
SO far I got a DC motor to run on AC but the AC motor has problems. It ran slow on the track. The magnets didn't help. Now I am thinking of a rewire job.


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## johnfin (Nov 28, 2009)

*Magnets*

So if it was a great thing why did they drop it. More traction sounds better.
Law of physics: "you dont get something for nothing" hence, sure you get traction but at a loss of power?


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## T-Man (May 16, 2008)

I am not a fan of magnatration. Very few of my engines have it. I don't believe they have dropped it. I thought it was one of their add ons.
I checked their book and traction tires are used now on the lower end models. So tires are better, with the loss of weight from a plastic shell.


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## servoguy (Jul 10, 2010)

Magne traction is available in new locos. I have a Santa Fe "El Capitan" set and the loco has both traction tires and magne traction. 

Magne traction does not affect the power of the loco. However, when a loco goes around a curve, the wheels have to slip because the outside rail is longer than the inside rail. If you watch your loco speed as they go around your layout, you will notice that the loco will slow down when it goes around a corner. This is caused by the friction increase due to the wheels slipping. Now if you add magne traction, it increases the force between the wheel and the rail, and so the friction increases. Ditto traction tires. So the increased traction we like with magne traction and/or traction tires has a down side, and it is the increased friction when the loco goes around curves. 

Real trains don't have this problem as the curves are much wider than the ones we use for our models, and the wheels are tapered so that the wheels actually steer around the curves rather than slipping. Some of the newer Lionel cars have wheels that have a steep taper to help them go around curves without slipping. 

I have a 2333 F-3 diesel which does not have magne traction and it is by far the best runner I have a low speed. It has two motors, so it will easily pull more than 30 cars on level track. However, I can't get the couplers on the PW cars to stay together with that many cars, even if half of them are the newer cars which roll very easily. 

Bruce Baker


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## Reckers (Oct 11, 2009)

T-Man said:


> Magnets help traction.
> More drivewheels help traction
> Still 25 words or less.
> 
> ...




I do appreciate the comment, T-Man. I was afraid mine had passed unnoticed!


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## Big Ed (Jun 16, 2009)

servoguy said:


> Magne traction is available in new locos. I have a Santa Fe "El Capitan" set and the loco has both traction tires and magne traction.
> 
> Magne traction does not affect the power of the loco. However, when a loco goes around a curve, the wheels have to slip because the outside rail is longer than the inside rail. If you watch your loco speed as they go around your layout, you will notice that the loco will slow down when it goes around a corner. This is caused by the friction increase due to the wheels slipping. Now if you add magne traction, it increases the force between the wheel and the rail, and so the friction increases. Ditto traction tires. So the increased traction we like with magne traction and/or traction tires has a down side, and it is the increased friction when the loco goes around curves.
> 
> ...




Did you all ever see this explanation?

http://www.wimp.com/trainsstay/


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