Thank you all for your detailed responses. I had no idea locomotive or can motors could be that powerful. I'm actually not using it for a locomotive, but rather on a swinging ship model amusement ride. My theory is to rest the boat on a flywheel, attached to the motor, and (hopefully) the torque will be enough to swing the boat.
You can check out A Line Products. They have very fine motors for locomotives.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
The old rubber-band drive Athearn Hustler switcher made a good rail-rod. I wound electrical tape around the axle drive drums to drop the ratio a bit, but it still went fast enough on 12 volts to derail. I cut the sides of the hood out to expose the motor, and to show the commutator sparks.
Mostly I am a super-scale rivet counter type of model railroader, but that diesel switcher rail-rod suits me, in my moments of confusion between hobbies. Slot cars are my other hobby, natch.
See you on SCI? HRW?
There are many, many motors that resemble HO locomotive motors, but are wound differently for different purposes, including use as racing motors in slot cars. RPM up to around 40k are available, with prices ranging from $10 to $30. Many of these high-revving motors are dynamically balanced to deal with the vibrations inherent in high RPM. NSR brand motors are recommended as the smoothest, and are available in two can styles that may (or may not) fit existing locomotive frames. If you go into the "pro" level of slot car motors, you can obtain handbuilt motors in the $40 to $200 range that rev to 100k or more (on 12 volts), but current draw is extreme (high amperage indeed).
This is my list of current (and past) slot car motors, including some old open-frame Pittmans and Tycos at the bottom (filed under V for Vintage). I've tested some for RPM and torque:
http://slotcarnews.blogspot.com/2007/02/slot-car-news-motor-list.html
Specifically, the five-pole Pittman DC 65A, 195, and 70 were of great value as HO loco motors, in days past, but have been rendered obsolete by can motors, due to the can motors smaller size per unit of power output, and cleaner electronic signature.
The above site also has a brief explanation of how power is derived from stall torque and no-load RPM), with links to other sites that go deeper into motor performance (the MIT site is recommended). I also suggest you study the Mabuchi Motors website, which is easy to find through Google. If you get into that, bear in mind that Mabuchi sells many motors with custom winds that are not accounted for in their listings. They also require orders to be a minimum of 10,000 units!
For HO model locomotive use, motors that rev about 8-15k (no load) are optimum for the gears and loads we use. Motors with extremely low torque may rev to 25k no-load, but slow way down under load. On the other hand, high torque can motors are rated low for RPM end up operating in the same RPM range as the low torque motors.
DCC has required low-amp motors that emit very little brush noise (electronic, not audible noise), thus the proliferation of more expensive can motors. On the other hand, Bowser has a can-motor that sells for $8.00 which will work well in a variety of small and medium sized locos.
Low speed requirements have lead to the inclusion of flywheels and skewed armatures, which enhance very low RPM running without "cogging" (jerking from pole to pole) The low speed requirement pretty much rules out the use of three-pole racing motors in locos, which have very rough low speed characteristics.
If you are interested in a smooth running loco, flywheels are only one part of the picture. A high quality can motor may not need a flywheel at all, if it can rev at very slow RPM without cogging, and the power train is free of binding or gear-induced vibration.
Thanks for the detailed info, Fred. I did not think about increasing the wheel diamter, or using some gearing. Good idea!
You do realize that most of the motors used in HO and N locomotive run at 8,000 to 15,000 RPM at full voltage. You omitted the K following the RPM specs.
Are you truly looking for a 30,000 to 40,000 RPM motor? Bearings and balance and noise all become much more of an engineering issue at that kind of RPM. Stock bearings won't take the extra friction heat, balance has to much more precise to avoid damaging vibrations, and the noise of the rotating armature is increased and pushed into the uncomfortable part of the human audio frequency range. Such motors, if they exist, are going to cost considerably more than our locomotive motors.
A can motor is a DC permanent magnet motor that has the magnetic pieces molded into a cylindrical shape around the armature. A metal enclosure ("can") surrounds and protects the magnets and the commutator and brushes - and serves as the motor frame for the bearings. Can motors are generally more efficient than open frame motors that have the magnetic field generated by a magnetic material block and transmitted to the opposite sides of the armature through iron or steel pole pieces that also serve as the motor frame.
Model railroading would prefer lower RPM motors for locomotives because of the steep (and high friction and noisy) gear reductions required to get scale speeds using high RPM motors. Unfortunately, the smaller the physical size of the motor, the faster it tends to turn at a given voltage to generate the requisite power. But motors used in model locomotives are not specific to that purpose - they are general use motors culled from large catalogs with the most suitable specs at a reasonable price for locomotive use. You may be able to find something more suitable for your application in a search through motor manufacturer catalogs.
Flywheels gain far more rotational inertia by increasing diameter (square of the radius) than they do by increasing RPM. And you could always step up the flywheel RPMs from the motor through gears or belt drives used in the opposite manner as gear reductions. A 1:2 or 1:3 gearing or belt RPM increase ratio would work quite well with existing model motors at generating your desired RPMs. But bearings and noise and vibrations are going to be issues to deal with. You can get more rotational energy storage by doubling flywheel diameter than by doubling or tripling RPMs. And balancing a physically larger flywheel is actually easier.
my thoughts, your choices
Fred W
Are there any company's that sell just model motors? I know it's a vague and general question, but I'm looking for a fairly high RPM (Say 30-40+ rpm) motor that can be used to spin a flywheel.
The majority of the motors I have found on walthers and other sources are 15 rpm max. Anybody know of any others? What exactly are "can motors?" Can engine motors be used for other purposes?Thanks in advance