motor vs flywheel motor

[union pacific 844]

 what the differences ? one of my bachmann 4-8-4 has it and one don't?

[damonlee22]

The idea behind flywheels was to improve the ability to coast and not have jerky starts and stops. Early in the use of flywheels a lot of motors were 3 pole and the flywheels did help to smooth out the jerks at low speed.

[Doneldon]

844-

Flywheels are used the same in all applications from large industrial plants to model trains: to smooth out pulses of power and to maintain motion when power may be intermittent. They are commonly found on steam engines, both mobile and stationary. However, they are much harder to see on a moving steam locomotive. That's because they aren't flywheels per se, but are disguised into the heavy driving wheels with their counterweights and the massive (literally, in both senses of the term) side rods.

If you think about it for a minute, steam engines (both kinds) are naturals for a flywheel. Steam engine power strokes are seriously big followed by nothing until the next power surge. The moving mass (weight) keeps things going until the next power stroke, whether the flywheel is a true flywheel, like on a steam tractor or a flour mill, or a masked one like the heavy machinery hanging on the sides of a steam locomotive. In addition, the fact that a flywheel or its equivalent maintains much of the momentum of the mechanicals means that the power doesn't vary between all and none but rather between all and quite a bit. The attenuated difference between the power stroke and the non-power time means the motion is more uniform. This usually a desirable feature in an industrial setting, as well as a way to minimize wear and tear on the equipment and personnel.

                                             -- D

[jbrock27]

Myself, I am a big fan of flywheels over no flywheels.  But, I run diesels, no steam.  I know Doc does not agree with me on this, but I have always felt that a motor with flywheels provided smoother running and more torque and a result is a better motor.
If given the choice, I like to buy a motor with 2 flywheels. 

[nfmisso]

Doneldon - steam engines, as used on locomotive are double acting - they pull and push, both forward and backward motion of the cylinder is a power stroke.

jbrock27 - flywheels do not provide additional torque - they provide no increase in energy output at all.  All that flywheels do is smooth out the torque ripple, and provide longer coasting if the power is interrupted.

Flywheels provide additional rotational inertia.  Most precision electric motors are designed to minimize inertia because inertia is the enemy of acceleration. 

Current technology allows for low cost electronic circuits that provide the same effect as flywheels, when desirable, at a lower cost; and they are able to reduce the inertia effects when that is desirable. 

Generally DCC and BEMF controls function better with less inertia (no flywheels).

[Doneldon]

(1) Doneldon - steam engines, as used on locomotive are double acting - they pull and push, both forward and backward motion of the cylinder is a power stroke.

(2) Flywheels provide additional rotational inertia.  Most precision electric motors are designed to minimize inertia because inertia is the enemy of acceleration. 

(3) Current technology allows for low cost electronic circuits that provide the same effect as flywheels, when desirable, at a lower cost; and they are able to reduce the inertia effects when that is desirable. Generally DCC and BEMF controls function better with less inertia (no flywheels).

nfm-

(1) I'm well aware that steam engine cylinders are double acting. Nevertheless, there is a substantial and cyclical variation in the force exerted by those cylinders. That's why rods and counterweights are needed to attenuate both the amplitude differences and the pounding on the machinery and track.

(2) Inadequate acceleration is not a problem with model trains. On the contrary, our trains accelerate way too fast. So ... the tendency of flywheels to retard acceleration, to the minimal extent they actually do so, is an asset, not a problem.

(3) Electronic circuits do not necessarily operate better to control inertia and momentum than simple physics, nor do DCC and BEMF operate inherently better without flywheels. The fact is that the electronic paradigms or models become much more complex when there are physical enhancements to the drive train whose effects vary as speed changes. And, not only does the algorithm become more complex, but the electronics would need at least one additional information input to account for the varying effects of a flywheel: either the speed of the flywheel or the speed of the locomotive. That would require either a counter on the driver axles or drive shaft, or an accelerometer. The electronics could then consult a software table for the actual value to insert into the formula or algorithm. This makes the control system more physically complex and more electronically complex. That added complexity costs money and it is simply cheaper to design and build a system without a flywheel, without the additional hardware, and without the more elaborate mathematical formula. In this case, simple is both cheaper and good enough. We cannot, however, infer from this that the electronics are better than the physics or the physics plus a more complex paradigm.

Please note that I am not saying that the electronics are not, in fact, superior to the physics. All I am saying
is that your inference to that effect is inadequately supported by the data.

                                                                                                                -- D

[Desertdweller]

NFM, Don,

Think of what you guys are saying here.  You can approximate the action of a flywheel by a complex electronic solution.  Or, you can simply fit a flywheel to the motor shaft.

The electronic solution will still be vulnerable to interruption of current (unless it incorporates a capacitor, adding further complexity).

Why resort to a complex electronic solution to duplicate the effect of a simple mechanical device (perhaps the simplest of all, a wheel) that even a caveman could understand.

Rube Goldberg would be proud!.

Les

[jbrock27]

If you say so NFM, but on my layout ALL the locos I have with flywheels perform better than those w/o.  And that includes newer models.  Not to mention the added weight of the flywheels, which to me is a good thing.  I will still choose the flywheel motor thanks.
And I must say, I have read a lot about flywheels allowing a loco to "coast" but in my experience, even though those locos I have with flywheels run very smoothly with no binding, I rarely see them coasting to a stop.  Maybe I am just not seeing it. 

[Doneldon]

NFM, Don,
Think of what you guys are saying here.  You can approximate the action of a flywheel by a complex electronic solution.  Or, you can simply fit a flywheel to the motor shaft.

The electronic solution will still be vulnerable to interruption of current (unless it incorporates a capacitor, adding further complexity).

Why resort to a complex electronic solution to duplicate the effect of a simple mechanical device (perhaps the simplest of all, a wheel) that even a caveman could understand.

Rube Goldberg would be proud!.

Les

Les-

I'm not arguing for the electronic solution over the flywheel. I'm stating that a flywheel is a great help, a help which cannot be easily replaced by electronics in locomotives which are not DCC. However, I must confess that I don't think the addition of a flywheel and its accompanying complexity is warranted for DCC locomotives.
                                                                                                                                                 -- D

[Desertdweller]

Don,

I know.  Like jbrock, I have some locos with flywheels and some without.  Without exception, the ones with the flywheels are smoother.

I have no experience with DCC.  Perhaps a combination of flywheels and DCC could produce the smoothest result.

Generally, it seems to me that the simplest solution to a problem is usually the best.

Les

[jbrock27]

I should clarify, that I also have zero experience with DCC.  If I did, I leave room for the possibility my mind could be changed

Les-did you see my 'thank you' to you and Jeff Ward for your help with my GP60 directional light project?  I posted it under that topic,  but in case you did not see it, thank you again.  I was very pleased with the results.
And my son is too!

[richg]

About twenty five years ago I modified a HO Tyco 4--6-0 and Tyco 0-6-0 using NWSL MDC replacement gears and Sagami can motor with flywheels as an experiment. The parts cost much more than the locos but it was an experiment.  Both locos had to be converted to the MDC compound gear arraignment which was the biggest challenge.
The motors had to turn at a little higher speed because of the gear reduction and where mounted in a bath caulk setup to eliminate vibration in the loco. Plastic shells can amplify motor and gear noise quite readily.
I used a DC power pack I modified for PWM and those locos could crawl as well as any decoder equipped loco I have ever seen.
Bottom line, good motors, flywheels and good pickups, plus clean track.

I have to include, this stuff is not plug and play but NWSL has a great motor/gear planning arrangement. I bought all the paper work when NWSL was still in Seattle.

Rich

[jbrock27]

I just ordered and received thrust washers and Conducta lube from NWSL-I thought it came from Seattle.  ??

I wanted to point out there are at least a few manufacturers that make DCC run diesels with flywheel motors.

[richg]

I just ordered and received thrust washers and Conducta lube from NWSL-I thought it came from Seattle.  ??

I wanted to point out there are at least a few manufacturers that make DCC run diesels with flywheel motors.

Dave and Lynda Rygmyr purchased NWSL in 2008. Under the parent company, OSO Railworks.

Your parts might be from a company who also sells NWSL parts.

The thrust washers are nice because you cut a slit and slip them over a shaft without having to remove any parts.

Rich

[Desertdweller]

jbrock,

I'm happy to be able to help.

Les