@Ken

Ken,

I used those in the Athearn radio controlled crane I built. Remember?

They have some gear noise but are generally quite. It depends on how they are mounted. Some material could act as a sounding board. Also the 300rpm will get even lower once you go through a worm and wheel. So those are my observations from the one's I've played with.

Bernd

Thanks, Bernd

I do, Bernd, and it's a big part of the reason why I am considering them at all.

I'm wondering if I could design a mount which help to damp the noise, perhaps by surrounding the gears with plastic.

I would use a 1:1 gear set, such as these, from Motionco.  I am also trying to figure out how to draw a set of bevel gears in 3D, so that I can try having them made at Shapeways.

Great little motors

Ken,

Ditto with Bernd, these are great little motors. They will run very quiet if not run near top speed. Be careful about the gearing for a loco-- 300 RPM is way on the slow side. I lube the gears with Nano-oil and they are smooooooth. I am impressed with the torque they put out-- quite high for their size. I have actually ripped apart plastic linkages with them, but I was using a 30 RPM unit.

FYI, there is a small stepper motor out of China that uses nearly the same gear assemblies-- they are interchangeable! I've taken a high ratio gearbox off of one of these and put it on the stepper (usually found with a low ratio). This makes for an interesting geared stepper with high torque.

Best regards,

Geoff Bunza

They will run very quiet if

Interesting observation - how close to top speed is practical without excessive noise?  There are 400 RPM versions available, which (with a 2:1 gear ratio) would give me the ability to use half or less of the total available speed range - would that be more reasonable? 

You're right.  I double checked my math, and I made a goof.  Looks like 700 RPM would be a lot better.  Here's my logic.  I welcome any advice or opinions.

I usually use 60mph as a target speed.  It's more than most steam freight locos were designed to do, or most steam era track was good for, and it's definitely more than I want to run my models.  It's also convenient, since 60mph equals 1 mile per minute.

A 57" driver (as used on the loco I have in mind) has a circumference of ~7.5' ((57"/12)*pi), and will have to rotate ~700 times to cover one mile (5280'/~7.5').  Thus, 700 RPM=60 mph, so 700 RPM seems like a good axle speed target.

@ Ken

That was one of the motors I had been considering for MDC HOn3 conversions.  I don't need speed.  I need torque.  Any reason not to usethis  particular motor in a narrow gauge Consolidation?  Or should I look at the higer RPM model?  Ken, you know my proposed layout.  Let me know what you find out.

There was another that I saw that claims it will drift along during power loss due to dirty track or for a problem with a turnout frog.  I guess it has an internal flywheel.

Den

@ Den

There are two potential issues that I can see.  The first is size - an HOn3 locomotive is small enough to be a tight fit for many motors, even those which fit in a small standard gauge locomotive.  The other, and probably more significant, is speed.  You've probably got something in the range of 30:1 reduction in that Consolidation.  For a top speed of 30 mph, you'd need a motor running at 7,500 RPM.  The highest speed I saw for these motors was 4,000 RPM, which would limit you to about 16 mph flat out with no load.

@ Ken

Not trying to hijack your thread.  I'm just trying to learn something here.

According to what I read those Consolidations took 2 hours to go 18 miles.  That would be 9/hr unless there were stops being made along the line.  There were a few stops for passenger service, but there wouldn't be that many passengers either.  What motor is recommended?  I have the original MDC motor for those kits.  I will measure it.  Maybe we can make some comparisons?  I also realize I can set a CV for the max speed on an electric motor.

Thanks!

Den

Gearing

Ken,

First a question, have you considered the 3 mm dia. D shaft on the output end? Don't know if they gave that dimension or not. I measured one I have. I think all the output shafts are of that dimension.

Idea here, you can make a "speed up" gear set here. I see they have 2:1. I also see the dimensions. Might not work. Also see that the bores are 3mm on the gears. So for a 1:1 might be workable.

Can't get away from spur gear noise. But the idea of enclosing them might work. Might also work as an amplification chamber such as what happens with DCC sound systems.

It would be interesting to see if you could print the gears. Personal opinion is that they would be to rough. Have you tried any of the ones you printed already?

Bernd

The Life of Pi

A 57" driver (as used on the loco I have in mind) has a circumference of ~7.5' ((57"/12)*pi), and will have to rotate ~700 times to cover one mile (5280'/~7.5').  Thus, 700 RPM=60 mph, so 700 RPM seems like a good axle speed target.

Er, uh, Ken, actually a 57" driver is 179" plus small change in circumference. That's 14.92 feet in circumference, not 7.5. 60 MPH for a 57" driver engines is 354 RPM (rounded to nearest RPM).

For quick calculation, 336 RPM gives you driver diameter speed. The 300 RPM of the motor you show would be roughly  90% of driver diameter speed. For a 57" engine, that would be 51.3 MPH. That's actually not a bad top speed. For an 80" driver 4-8-4, 300 RPM would be a top speed of 72 MPH. For a 63" driver engine, that would be just under 57 MPH. Sounds like a good motor to use with a 1:1 final drive.

OK, 300 RPM is actually 89.3% of 336, but why quibble? In any case, keep the 336 RPM in mind for reference. It makes it really easy to calculate the gear ratio necessary to gear down a motor with a known maximum RPM to produce a given top wheel rotational speed for any engine. A 10,000 RPM motor geared 30:1 will produce 333 RPM at the axle (and wheel rim) - pretty close to the 336 mentioned above for driver diameter speed.

Mike - who is quite well aware how annoying he can be.

Another math goof - ugh!

Sigh.  You're right, Mike.  I don't know how I messed that one up, unless I divided in half first, aiming for radius, and then changed my mind.  That's for pointing out my mistake, as it makes a huge difference!

I have had success with the 44 tonner gears, though they needed a bit of breaking in.  I want to try printing some gears in FUD, as it's a lot finer and a lot harder.  I'm even looking into trying to design some small hypoid gears - I have a program which will do it, and am trying to get it to output a CAD file for me.  I also want to try some 1:1 helical gears in either FUD or brass.  If it works, I'll have a source for custom gears at a reasonable price.  If not, I won't be out too much.

Given the range of ratios available on the gear motors, I would prefer to adjust the system there if possible.  Other than a 1:1 0.5 mod set, all the gears on that site are 1 mod or larger.  Of course, if I figure out how to design my own gear sets, anything is possible, within reason.

I wonder if it would be practical to completely enclose the gears, and surround them in oil?  Aside from better lubrication, the oil might dampen the noise.  Of course, it might also rob significant power.

@ Ken

Try Geoff's Nano-oil suggestion.  Seems he is ahead on that one.

Den

I'm not sure about enclosing the gears and immersing in oil

Especially with Nano-Oil.  I would be concerned with leakage unless you have a sure-fire way of preventing it that wouldn't cause binding/friction issues itself.