If you added traction tires, any extra weight would really be overkill. Be careful not to overtax the motor, since it can probably pull more than it should.
Nelson
Ex-Southern 385 Being Hoisted
To be honest,
I haven't really tested this engine under load, so I don't really know what it is capable of pulling. It may be a non issue after all. I was just surprised when I added that large piece of lead in the boiler that the engine slowed down considerably, with no load. I have since put the factory weight back in and the performance seems fine. There is no binding in the mechanism, I am anal about free rolling mechanisms. I use silicon fuel tubing to connect my motor to the gearbox (short length, maybe 1/2"). I actually cut grooves in the rear set of drivers and added traction tires so I'm hoping it is a good puller when I get round to buying more passenger cars. I actually have purchased some bullfrog snot but haven't used it on anything. Thanks for all the technical responses. Interesting, but honestly the math is lost on me. I'm into the hobby more for the art not the science.
never mind.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
So let me undersatnd this 13000 rpm =lower torque, higher speed, 8500 rpm=higher torque, lower speed. Is that correct?
PRR_in_AZI did regear with a precision scale gear box 27:1 ... What is better for the gearbox ratio I have? I want this PRR K-4 to pull around 8-10 heavy weight passenger cars up a 2.0% grade.
From the numbers it seems that should be a fairly good combination. That seems a little slow for a K4 but it should have plenty of pulling power. With that high of a gear ratio it should not be bogging down the motor. I stumped. Are you certain the gears are all turning freely and there isn't any binding in the drive or valve gears?
I installed a NWSL Sagami in a Rivarossi Pacific that was capable of spinning the drivers when stalled, and that's with traction tires and a fairly high speed stock gear ratio. I find it hard to believe that any but the smallest of their motors would have any problem moving a brass loco, heavily weighted or no, unless there are serious mechanical or electrical problems as others have mentioned.
One problem I did find with the motor was spongy performance; it would be sluggish at start up, but then would get faster as it got warm. I finally took the end bell off the motor (three small set screws, IIRC, and you have to mark it for orientation to get it back on in the right position), and discovered that the factory oil was all over the brushes and commutator. I degreased them with contact cleaner, and now it has a consistent speed range.
CB&Q:
I could be wrong, but I wouldn't think that there would be any difference between DCC and DC when installing the Tomars. What they actually are is a form of additional pickup for the 'live' side of the locomotive and tender--shoes between the live drivers and on the opposite side for the live tender wheels. The shoes come with very adequate instructions for this. In fact, they're a solder-less installation that is quite easy. One thing I like about the Tomars, and prefer them over conventional 'wipers', is that they actually slide along the railhead and are not dependent on the cleanliness of the wheel treads themselves.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
Small DC motors are usually rated for torque at stall, and for RPM at no-load. Both ratings are at 12 volts, most often. Power is the product of torque times RPM, but an electric motor torque drops to zero at its maximum RPM, and the RPM is (naturally enough) zero at full torque, which is at stall. About halfway between is where the max power is developed. That is, a motor develops half its potential torque and half its potential RPM when it is producing max power.
If you are trying to squeeze passenger-engine power out of a motor, it would ideally be geared so that it is running at about half the max rated RPM up the hill, while pulling a load. It would be good to know at what speed you want to pull your 10 car train up the 2%. Then, figure out the whole shebang with your known 80" driver diameter, back figured through the gearbox at 27:1, and into the motor. Etc. You can easily get lost in the calculations. The rule of thumb is that the biggest motor that fits inside is the motor you should use. I wouldn't worry too much about ratios and speeds, unless you really enjoy all that (as I do).
But first, I suggest you take a good hard look at the mechanical functioning of the drive, and check for any binding that could be originating in those after-market chunks of lead.
I did regear with a precision scale gear box 27:1 I think. Original motor was open frame 70's vintage. Don't know the rpms So let me undersatnd this 13000 rpm =lower torque, higher speed, 8500 rpm=higher torque, lower speed. Is that correct? What is better for the gearbox ratio I have? I want this PRR K-4 to pull around 8-10 heavy weight passenger cars up a 2.0% grade.
I would also check for mechanical problems inside the boiler, in particular, some of that extra weight you added might be dragging on a gear or pushing a shaft out of alignment. Generally, adding weight to an engine will not lower the speed running light (unloaded, without a train).NWSL can motors would indeed follow the same practice as older motors, in that the rated current is usually the safe operating current. You can overload them for short periods of time, like ascending a typical model railroad grade (say, a minute or less) but longer overload periods of several minutes could result in burnout. Loading a motor until it stalls can also overheat a motor to death.
The rule that was always mentioned years back is you can add weight until the drivers are still slipping and the current draw equals the rated current for that particular motor, That was in the days of open frame motors .I would guess that would apply to todays can motors.
PRR_in_AZI usually repower most of my engines with NWSL can motors. ... Anyone have any opinions on this or can suggest a better quality can motor?
The 18x33 motor has twice the torque at 8500 rpm.
You can use Kadee #5 couple springs for the tender wheels. I and others have done that. I used the below suggestion.
http://www.darksidemodeler.com/tender_wipers/
Using a thin copper clad pc board, cut a thin groove in the center, lengthwise so you have two copper sides. Solder small diameter phosphor bronze wire so the wire is up against the back of the metal part of the driver.
Brass
http://www.7thstreetgroups.com/shops/7th_Street_Shops_DCC_Installation.htm
http://www.nmra.org.au/Hints/Brass/Brass.html
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Twhite
Speaking of using the Tomar track sliders with DCC Equipped brass is there a tutorial anywhere on installing them when using DCC , Finding that while my 2 decoder equipped brass engines perform fairly well they will need the sliders to get them up to peak performance.
The speed getting limited at a certain point sounds like an overloaded power supply. An ammeter for the main track power should be pretty easy to hook up to find out.
I do agree that the factory weight of brass is usually enough, unless it's unbalanced. Proper balance really makes a difference.
_________________________________________________________________
Thanks Tom - I'll check out the Tomar pick-ups. I guess my question has been twofold:
How much weight is too much?
I guess I've come to the conclusion based on responses so far is that the driver's should slip under heavy load and be balanced over the drivers. I guess I'll stick with the factory weight for now.
Does the throttle speed being limited have to do with:
Electrical pick-up?
Decoder?
Motor RPM?
Don't know the amps. I really do need to hook up a meter but I am still fairly early in the construction process and not sure where to put it (yet). The Zephr is rated at 15V AC 3A. Currently I'm using NWSL round can motor 16mm x 30mm long. The website said it was good for medium steam and that's what I have it in a 4-6-2.
Two things: Brass locos pick up from one side of the locomotive and the opposite side of the tender. Most newer DCC or dual-mode steam like BLI and Spectrum have all-wheel pickup, on both locomotive and tender, doubling your electrical conductivity.
I run 98% brass, but I'm DC, and the older brass I've re-powered with NWSL cans run extremely smooth and are very responsive throughout the speed range. As my older open-frame motors reach past their prime, I re-motor them as a matter of course.
Generally speaking, older brass is sufficiently weighted as is, seldom is additional weight needed, at least as far as I've found. For brass that NEEDS additional weight, make sure that you're balancing the weight equally in the boiler, and that the loco is neither 'front' or 'rear' heavy. It's not the additional weight that improves running and hauling quality as much as it is where you put it. If the weight is distributed so that it's equal over the drivers, then the loco should run very smoothly and haul very well. Most of my brass haul very well, and 'balancing' the weight in the lighter ones has improved their hauling ability a lot.
One thing that might help your conductivity is to augment your wheel pickup with Tomar track sliders on both locomotives and tenders. I do this as a matter of course now, and the improvement in smooth running is pretty darned remarkable. They're phosphour bronze, which doesn't tarnish, and almost invisible between the loco drivers. Not only do they improve pickup, they also help to keep your railheads clean. I understand that they work extremely well with DCC.
Hope this helps.
Sounds like you've got heavy enough wiring. What's the amperage rating of the power supply? Do you have an ammeter connected to the main track power (always a good idea)?
When you run your weighted brass, can the drivers slip? Weight is always good, but it shouldn't be so much that the motor can't slip the drivers. What size of motors are you using, anyway? I know available motors pretty well, so if weak motors are really the problem, I may be able to point some stronger ones out for you.
Maybe, but I think I'm using 12 guage solid core for the bus and something like 22 guage for the feeders. I have them spaced about every 3 feet. There's no noticeable drop in performance at the same spots on the layout which would lead me to question the feeder wires and bus were inadequate in certain spots. I also have a BLI PRR M-1 (paragon installed decoder) which runs like a champ on the same system and is nearly as heavy as the one engine I "leaded" up. When I removed the lead and replaced the factory lead back in the engine the performance improved. Another perplexing thing is that this engine's top speed seems to max out when the throttle is less than two thirds open. Again the BLI engine has the full range of the throttle. I'm using the Zephr system with no additional boosters but my layout isn't that large (8x10).
It sounds like you may have inadequate power feeds to your track which is causing a lot of voltage loss or not enough amperage on the rail. You may need to use a heavier gauge wire for your track feeders and buss wiring.
Adding weight should not cause a loss of performance unless you're somehow adding several pounds of lead.
What I mean by "weak" is that when I try to load the engine boiler up with lead to improve pulling power, I can actually tax the motor so much that it can barely pull the engine around the track. I thought you can never have too much weight in your locomotives. Does this make sense? I've never heard anyone complain of this before.
I think you'll need to define "weak". Do you mean that the motor won't turn the drivers fast enough to get you to the speed you want to go? Or do you mean that the motor seems incapable of turning the drivers in the first place because there might be too much mechanical resistance?
Hi all,
I like brass engines (steam) and run digitrax dcc and I usually repower most of my engines with NWSL can motors. The motors seem OK but not great -they seem a little weak. Anyone have any opinions on this or can suggest a better quality can motor?
Thanks,
Chris