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On the original Varney drive doesn't the motor rotate on the trucks? I worry that with a fixed motor with a belt drive would constrain the trucks such that they will not rotate around curves properly. Also you seem to imply that the counter weight is not fixed to the motor shaft, but that it somehow rotates independently, I've never seen that. But then I have exactly 2 Athearn Diesels (a PA-1 and a PB-1) and the counterweights on those units are fixed to the motor shaft. Should be interesting to see what you come up with!
 

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Discussion Starter #22
Different but the same principles apply. Looks like dual smaller flywheels with one on each end. I have heard good things about the Ahearn's, I have a few but none with flywheels.
On the original Varney drive doesn't the motor rotate on the trucks? I worry that with a fixed motor with a belt drive would constrain the trucks such that they will not rotate around curves properly. Also you seem to imply that the counter weight is not fixed to the motor shaft, but that it somehow rotates independently, I've never seen that. But then I have exactly 2 Athearn Diesels (a PA-1 and a PB-1) and the counterweights on those units are fixed to the motor shaft. Should be interesting to see what you come up with!
No, on the unmodified Varney the motor, drive unit, and trucks are all fixed together and rotate as one on a pivot. On this previous owner modified Varney the motor is fixed on a stage and does not rotate with the drive unit or truck. Necessary to avoid the bulky flywheel to hit the sides of the shell during turns.

A concern of mine also that the fixed motor will limit the travel of the truck, but there is a lot of give with that coiled spring so we will see.

My modified press worked great. It allows precise movement. I backed the flywheel off the armatures shaft about an eighth inch which should align the two pulleys but we will see. Also media blasted the frame and the trucks. I usually disassemble these before hand, but that's not necessary. I will disassemble both and clean and paint later.

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So it's just the shaft of the motor and the flywheel that form the bearing or is there another sleeve? I guess I don't quite see how the flywheel stays fixed from moving on the shaft.
 

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Discussion Starter #24
Curiosity got the best of me and I took it apart. It just snaps back together, no problem.
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The armatures shaft is soldered to a mass that has two independent weights that rotate outwards contacting the brass flywheel causing it to spin. Pictures are worth a thousand of my words.
 

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Wow. Well it's a little hard to see exactly how it's constructed. It's definitely not a solid flywheel pressed into the motor shaft...

Its kind of interesting to me at least to compare that, the "analog solution" against the DCC motor control digital solution ...
 

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Discussion Starter #26
Yes, inertia causes the two counterweights to expand outward contacting the drum causing it to spin. I can't see the benefit in this situation, but I'm going to keep it if it works. Right now the other working one is just to slow on the track. I don't think the PO ever got it to work, he had it wired wrong from the beginning.
 

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one thought is if each drum is not calibrated to some similar criteria, each will behave differently.
 

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It's called a centrifugal clutch. I know its not on the 2 different types of Ahearn motors I have. A surprising find!
 

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Discussion Starter #30
It's called a centrifugal clutch. I know its not on the 2 different types of Ahearn motors I have. A surprising find!
Thanks, that's the term I was searching for in my muddled mind. Got several examples on my model cars and air tools.
 

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Discussion Starter #31
Got everything cleaned up, and it runs. Just not great. Rubber band slips and nothing that I would put up with. So I got on ebay and found a motorized truck with both pulleys and a coiled spring drive band for $20, far less than what a machine shop would charge me to make a couple of pulleys. The two pulleys will replace the two flywheels and return these two locomotives back to factory.
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A far superior fix! You could have put a lot more money into the fixed motor only to have it be constrained to very large radius turns!
 

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I would like to get ahold of one of those to tear it apart to better understand it. I can get the idea that the flywheel would be used to keep the motor spinning but if it was floating that wouldn’t help much unless it was on some form of a clutch that only engages when the motor looses current. Seems to me like that flywheel isn’t doing a whole lot and that motor just runs really good
 

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There's a pulley off the wheels to the flywheel. So the motor makes the wheels to round, the pulley spins up the flywheel. That takes a little energy. Then to slow down the flywheel resists. Or that's what I get...
 

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Here's how I think it works. The motor shaft is fixed to the pulley (that goes to the wheels) and to the centrifugal clutch. As the motor starts to turn, the clutch starts to engage the flywheel. Faster it turns the the more the flywheel is connected to the motor shaft. Then as things slow down the clutch will eventually release the flywheel.
 

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These (Athearn?) flywheels came on a couple of recently purchased Varney F3's. Looks like they are built right into the small end pully. The is a hole in the outer end but a flat bladed screwdriver or Philips has no effect. Any ideas?


Could this possibly be the Kadee snap on Fluid drive system where you "somehow" Added various weight oils to change the momentum?? Never Never saw anything like this.
View attachment 540149 View attachment 540150
 

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Discussion Starter #38
These have weights that I think expand with speed and contact the outer barrel. When I have the time I'm going to take one completely apart and find out exactly what's going on.

Stay tuned.
 
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