TheRailwire
General Discussion => Product Discussion => Topic started by: Chris333 on October 23, 2021, 08:02:50 AM
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In this video at ~1:09:00 there is a new Kato motor listed as "slotless"
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Since I don't understand Japanese, I am clueless about the new motor. All I see is a static picture of the motor or 3 talking heads who are speaking a language I don't understand at all.
So, can you tell us what you know about the new motor, please?
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Some of the titles on the slides are "smooth, silence, torque, compatible", so I'd assume it's a compatible motor that's slightly quieter but with smoother drive characteristics and higher torque.
Conjecture:I wonder how much of that is related to the switch to PWM DC instead of variable DC from their power pack. Either way, since DCC also uses PWM whatever improvements there are should carry over to DCC.
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Conjecture:I wonder how much of that is related to the switch to PWM DC instead of variable DC from their power pack. Either way, since DCC also uses PWM whatever improvements there are should carry over to DCC.
I think a slotless motor no longer needs PWM. There's no cogging to overcome.
Jason
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There is 2 , a GM-3 and a GM-4 .
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Judging by the winding outside the iron armature (which is visible between the windings, it appears like a hybrid between regular iron-core armature and a coreless motor. the iron core probably has no slots in it, with multiple separate winding being the sort of seamless "poles".
Sort of like coreless motro that was turned inside out. Not sure what the point is, except maybe the wanted to come out with a motor that is nor cylindrical in shape. Leave it to Kato to keep on innovating the model train design. But then again, sometimes they "jump the shark" too. I guess when that thing gets out into the wild, we'll be able to asses its benefits. Or maybe when someone translates that video. :)
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A motor for which scale? KATO makes both.
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Slotless motors are designed to optimize smoothness and create predictable torque output with minimal non-linear effects. Commonly referred to as slotless motors when rotary and air core motors when linear, slotless motor designs place only copper phase coils in the air gap of the motor. These coils, when placed properly, interact with the permanent magnetic flux to create force or torque. Cogging torque is eliminated because the discontinuous iron teeth are removed from the motor air gap. Slotless technology is especially effective with direct drive precision systems because all torque is a function of phase current and there are no unwanted or uncontrolled torque disturbances from the motor
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I know nothing about the Kato motor, but I'm sure sooner or later we will see it in US models (if it works out).
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Chris, while the "slotless motor" is a new term for me, I can tell you that the Portesacap seems nothing like the Kato motor.
Portescap is a brushless motor it has more than 2 wires feeding it, and requires electronics to drive it. Magnet is its rotor, and the coils are stationary. This type of motors are used in electric RC airplanes and in many cordless power tools.
From what I see in the Kato slotless motor is that there are only 2 terminals feeding power (so it can be used in existing models, and the coils appear to be wound around some sort of an iron rotor. It likely has brushes too. Well, unless the coils visible in the video are stationary, and the magnet rotor is not visible (hidden inside the motor), and the electronics to drive the motor are also integrated inside. That doesn't seem feasible, but I guess one never knows for sure until we have the motor in-hand.
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It likely has brushes too.
Slotless motors appear to use Hall sensors instead of brushes.
Jason
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Slotless motors appear to use Hall sensors instead of brushes.
Jason
Correct, as I mentioned the Portescap slotless motor is brushless and requires electronics (magnetic sensors, driver transistors, sequencer) to drive it, but I also pondered about Kato's version of slotless motor which does not appear to require external electronics (it has only 2 power terminals). As such, it will require brushes to sequentially power the windings.
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Most of the key points of the video are pretty clear from the few English words on the slides, but the new motor took ~5 years to develop, they're very proud of it, it's very quite, very smooth (i.e., good low speed performance), and very strong. Part of the development was getting rid of vibration in the motor. It's a drop in replacement for the GM3 motor, so you can upgrade older models. It will be available at the Kato store at the end of the month, and in new models starting with releases in June or July (-ish). There was also some mention of needing to keep the track clean (i.e., if you have trouble with uneven movement, it's the track, not the motor). The price will be "not expensive" (no specific number was mentioned). In the demo, they didn't really have a mic near the demo track, but the first subway car had a GM3 motor in it (you can kind of see GM3 on the tape on top of the car), and it made noise that could be heard by those in the room (but not the video). The second subway car (with スロットレス on the tape) was claimed to make about as much noise as a trailer car (i.e., the clickety clack sound, but no motor sound). I think they mentioned something about it having brushes. They definitely did not mention anything about complicated circuitry.
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Thanks C62-2!
I can't wait to get my hands on one of these to dissect it. At least with this motor nobody will complain about straight-wound armature. :)
Sounds like this is a great development. It is nice that this motor is designed for retrofitting the models with the GM3 motors. I wonder if the new motor has lower rpms.
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Yes thanks. I found it on Twitter where most of the Japanese modelers seem to hang out.
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From the Twitter:
At the technology development corner, a demonstration exhibition of the next-generation motor "slotless motor" currently under development will be held! The stuttering during rotation called "cogging" is reduced to the utmost limit. In addition to being able to run at super slow speeds like never before, it has also achieved high quietness by suppressing extra vibration. Please take a look at the amazing performance
https://twitter.com/kato_team/status/1426788242872020998
They show an N scale model running.
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When the motor is available as a spare part, maybe we can get @mmagliaro to run some performance tests on it. I would love to see how it compares to Kato's (or any manufacturer's) coreless motors. Those exhibit no cogging, and have pretty high torque. I also understand that this motor is designed to be a direct replacement for the regular 5-pole straight-wound Kato motors, where coreless motor conversions require modifications of the mechanisms.
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When the motor is available as a spare part, maybe we can get @mmagliaro to run some performance tests on it. I would love to see how it compares to Kato's (or any manufacturer's) coreless motors. Those have exhibit no cogging, and have pretty high torque. I also understand that this motor is designed to be a direct replacement for the regular 5-pole straight-wound Kato motors, where coreless motor conversions require modifications of the mechanisms.
Ever since this thread started, I've been jonesing to get my hands on these to see what they can do. I have to say that after seeing
the 8mm and 10mm Faulhabers and Maxons, and then those tiny 6-pole Minebea 10mm motors you found, Peteski, I'll be very curious to see how good these Kato motors really are. And yes, form factor could be huge. If it's drop-in size for existing Kato motors, that means almost any Kato or Atlas diesel could be souped-up with a "drop-in" and that's huge.
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Yes, those tiny Mineba 6-pole motors are quite amazing! Too bad they are not designed for 12V (although we have ways to run them in N scale locos.
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https://twitter.com/shigemon1227/status/1461676606880038917/photo/1
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This seems to suggest the motor needs to be stuck to a large hunk of metal to get any torque out of it.
http://blog.morii.jp/article/189173040.html
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Ferrous or non-ferrous metal?
But seriously, I suspect that it is a translation error. It wouldn't make sense that a motor would need anything externally to make it work. The photos clearly show the chunky iron armature under the windings, and the magnets in the frame.
The text probably states that due to the chunky armature, there is lots of torque. The photos also appear to show that Kato uses those super-strong rare-earth magnets which they used in their smaller motor in GS4. That will also play role in maximizing the torque.
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There is a 2nd and 3rd page to the link above. It looks like he added a ring of "iron" around the motor.
http://mory.sakura.ne.jp/sblo_files/moriiyoshihiro/image/E5A496E383A8E383BCE382AFE4BB98.jpg
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There is a 2nd and 3rd page to the link above. It looks like he added a ring of "iron" around the motor.
http://mory.sakura.ne.jp/sblo_files/moriiyoshihiro/image/E5A496E383A8E383BCE382AFE4BB98.jpg
I guess I didn't venture far enough. That will concentrate the magnetic field (like in can motors), so in that case I can see how that will improve the torque.
That is a pretty meaty ring of iron! Unless the stock motor has really low torque, it seems to be a bit of an overkill for an average N scale loco. But he gets an "A" for effort. I can't imagine that Kato would design something which required a modification for making it usable.
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Some ideas that may or not be correct:
1. The Wire coils are much closer to the magnet, which may improve torque (not requiring a metal armature to transmit that magnetic field to the magnets).
2. There looks to be more coils with finer wire, so maybe a lower speed motor?
3. The "poles" of the coils appear to be split into subgroups. So 10 magnetic poles? This would not work unless they use an offset communicator. Where it would activate 2 poles a time: 1-4, 2-5, 3-7, etcetera. With one closer to a magnet than the other, you get a hi-low attraction as the poles pass the magnet and this could reduce cogging quite a bit. It could also REALLY reduce top end speed.
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In one of the photos which shows the commutator, it looks like it only has 3 segments.
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Any information on the dimensions of the new motor? I would love it if it was a drop-in replacement for Kato Mikados.
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Any information on the dimensions of the new motor? I would love it if it was a drop-in replacement for Kato Mikados.
Mike, reply #11 in this thread gives you info on the size: It's a drop in replacement for the GM3 motor, so you can upgrade older models.
For more info see that post.
GM3 unfortunately is the smaller version of the GM5 motor that is used in majority or Kato American prototype locos.
GM3 is the motor that Kato used in the American GS4 steam loco, and also in the NW2 switcher, so drop-in replacements for American prototype are limited.
But if that motor is as good as the hype, since it is smaller than GM5, it could be retrofitted into locos that use GM5 motors.
I also suspect that if this new motor is successful, Kato will also make a version replacing GS5 motors.
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More info on the new Kato slotless motor:
https://jnsforum.com/community/topic/4-kato-new-releases/?do=findComment&comment=232389 (https://jnsforum.com/community/topic/4-kato-new-releases/?do=findComment&comment=232389)
How's your Japanese? Note that the Kato compatibility list linked to mostly lists Japanese and some European models and has 3 sections of compatibility levels, the third being "not compatible." Kato is taking reservations now, so it should be forthcoming in the near future with part number 11-503-A.
Rich K.
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GM3 is the motor that Kato used in the American GS4 steam loco, and also in the NW2 switcher, so drop-in replacements for American prototype are limited.
Hmm, if so this new motor could push me over the edge to get the Kato GS4. Always loved that loco (the real one) but that 3 pole motor in the Kato model kept me from buying (yes, I have run one).
Mark
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Hmm, if so this new motor could push me over the edge to get the Kato GS4. Always loved that loco (the real one) but that 3 pole motor in the Kato model kept me from buying (yes, I have run one).
Mark
Mark, what is the problem with that motor? Yes, 3-poles, but it is the only skew-wound motor Kato uses in American-proto locos, with very strong rare-earth magnets, while the 5-pole motors utilize standard ceramic magnets, and are straight-wound.
With skew-wound 3 poles there should not be any appreciable cogging, and with the strong magnets, there should be ample torque. I also really don't see that much difference between any current 3- and 5-pole hobby motors. Yes, in the early days of N scale, there were plenty of sub-par (by today's standards) 3-pole motors, but I don't believe that this is the case anymore. I seem to recall that even our esteemed N scale motor expert, Victor Miranda conceded that a good skew-wound 3-poler performs as well as a 5-pole motor. I agree.
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And speaking about Victor Miranda, what ever happened to him? Last on was June 2, 2017.
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And speaking about Victor Miranda, what ever happened to him? Last on was June 2, 2017.
He's alive and well other places. A few months ago on the Facebook PRR Modeler's page @Lemosteam tried to get him to come back to post on some thread (I can't remember which) but Victor was able to fend off the effort.
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Mark, what is the problem with that motor? Yes, 3-poles, but it is the only skew-wound motor Kato uses in American-proto locos, with very strong rare-earth magnets, while the 5-pole motors utilize standard ceramic magnets, and are straight-wound.
With skew-wound 3 poles there should not be any appreciable cogging, and with the strong magnets, there should be ample torque. I also really don't see that much difference between any current 3- and 5-pole hobby motors. Yes, in the early days of N scale, there were plenty of sub-par (by today's standards) 3-pole motors, but I don't believe that this is the case anymore. I seem to recall that even our esteemed N scale motor expert, Victor Miranda conceded that a good skew-wound 3-poler performs as well as a 5-pole motor. I agree.
I don't recall Victor saying that. :D It was with Victor that I witnessed these motors. Anyway, we've been around the block more than a few times on this matter. ;)
IIRC, Kato corrected the other problem on the GS4.
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I don't recall Victor saying that. :D It was with Victor that I witnessed these motors. Anyway, we've been around the block more than a few times on this matter. ;)
IIRC, Kato corrected the other problem on the GS4.
Allrigthy then - thanks for the explanation. :| I think you mean FEF3 (which uses Kato's coreless wonder).
Some of us like chicken, some beef. I'm a pork man myself. :D IMO, that GM3 motor is more than adequate for the job. It is a small wonder with a big-motor "soul". I wonder how it would do with you under a double-blind test? ;)
Actually I have a problem with the Kato's coreless motor in the FEF3 and ESU LokSound4 decoder. I can't get it to run smoothly on all speeds, and the minimum speed is too fast. I even consulted with Kelley (who at that time worked for Kato and did the decoder installs and tuning of the Kobo FEF3 installs). He gave me a copy of the ESU sound project he used for those and I'm still not happy with the loco's performance (even after trying additional motor control tweaks). I bet if FEF3 used the GM3 motor, the ESU decoder would have no problem controlling it well.
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Allrigthy then - thanks for the explanation. :| I think you mean FEF3 (which uses Kato's coreless wonder).
Nah, I mean the GS4. I haven't seen the FEF run in person.
I wonder how it would do with you under a double-blind test? ;)
I would welcome the test! :D The newest 3 polers are impressive - I'll grant that. But for now, I still haven't met a 3 poler that I liked. (Come on Pete, the world needs more poles! ;))
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(Come on Pete, the world needs more poles! ;))
LOL! You do have a point. :D
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GM3 is the motor that Kato used in the American GS4 steam loco, and also in the NW2 switcher, so drop-in replacements for American prototype are limited.
But if that motor is as good as the hype, since it is smaller than GM5, it could be retrofitted into locos that use GM5 motors.
A new run of the GS4 is out - I'm wondering if they used the new motor (probably not :D).
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A new run of the GS4 is out - I'm wondering if they used the new motor (probably not :D).
You are likely correct. I suppose someone could contact Kato USA and ask. Too bad that Kelley (nightmare0331) no longer works there - he would know for sure.
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You are likely correct. I suppose someone could contact Kato USA and ask. Too bad that Kelly (nightmare0331) no longer works there - he would know for sure.
I have 50 of the newest run ones here for LokSound installation.
I'll pull one apart later and get pics for you Peteski ;)
Enjoy!
Kelley.
www.dufordmodelworks.com
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I have 50 of the newest run ones here for LokSound installation.
I'll pull one apart later and get pics for you Peteski ;)
Enjoy!
Kelley.
www.dufordmodelworks.com
Excellent! Thanks, and Happy 2022 Kelley!
Good to know that Kato retained your services as the Kobo decoder installer. Do they even still use the Kobo name?
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Excellent! Thanks, and Happy 2022 Kelley!
Good to know that Kato retained your services as the Kobo decoder installer. Do they even still use the Kobo name?
Slight correction on this...Kato opted to go their own way on this as I have nothing to do with the Kobo project anymore.
I built them their initial GS4 sample before I left that they could use as a guide.
These ones are for Lombard Hobbies and will be available through them and will feature upgrades that I'm betting Kato USA isn't going to do.
The Lombard GS4's with LokSound will feature separate independent mars light, changing out those horrible greenish orange LED's and installation of rear light.
Basically, they will receive this treatment minus the revised drivers, which the new run already has, and the install will be a bit more refined....
I have a feeling that 50 number will increase drastically also.
Oh well...never a dull moment or shortage of projects to work on. :)
Kelley.
www.dufordmodelworks.com
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Ah so this is an original run unit, potentially with that driver defect.
Thanks Kelley!
UPDATE: I checked the Kato parts site, and they only list one motor (926055), so I guess the current run is still the Triple. :D
This seems consistent with what C62-2 said.
It's a drop in replacement for the GM3 motor, so you can upgrade older models. It will be available at the Kato store at the end of the month, and in new models starting with releases in June or July (-ish).
Mark
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so I cracked open a most recent run GS4 (well, I started cracking open many, but I digress...)
A few observations on the most recent run...they recycled/rereleased previous stock numbers so you might find earlier units out there with the same stock numbers but earlier features.
In this case, this is a recent run of 126-0307 (4 sku's were recently released 126-0307, 126-0308, 126-0309, 126-0310) 126-0308 and 126-0309 are 'postwar black' that had actually been announced with the wartime black units that were originally announced with different stock numbers but cancelled in 2008 as the economy collapsed. The wartime black ones were made, but not in very large quantities. (126-0303, 126-0304)
Okay...I'm starting to head off on a side tangent here...
The most recent run....
The motor is exactly same as previous runs of GS4's.
[attachimg=1]
The drivers on all 4 sku's are of the revised type (obviously).
[attachimg=2]
In an unexpected surprise, they finally molded plastic boiler and cab grab irons instead of the metal ones with plastic mounting pegs. Back in the day we had discussed this on previous runs. Apparently someone on the manufacturing side realized that it easier to tool a new part (or parts) for the assembly process. The long vertical cab grabs remain wire.
[attachimg=3]
Obviously, the tender still has the same wanky setup to take an EM13 style decoder board and the L shaped clips and upper drawbar that is prone to electrical failures.
[attachimg=4]
Anywhoo...I thought I was done with ever touching one of these models yet here I am surrounded by a pile of them again. :trollface:
Hope the pictures and overview helps!
Kelley.
www.dufordmodelworks.com
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Oh well Kelley, Kato's loss of you seems like it is your gain (since you seem to still be doing large quantities of decoder installs/customization).
Thanks for the quick overview of the new GS4 release. To be honest, I have no problem with that skew 3-pole motor with rare earth magnets, but some people seem to be hung up on the "3-pole" thing. I'm curious about what you think of that motor.
I also wonder if the "new" driver bearings will be prone to dislodging from their seats in the chassis, like the GS4 redesigned replacement drivers did (that Kato sold to replace the cracking-prone original drivers). Max Magliaro developed a styrene insert to prevent that from occuruing.
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Oh well Kelley, Kato's loss of you seems like it is your gain (since you seem to still be doing large quantities of decoder installs/customization).
Thanks for the quick overview of the new GS4 release. To be honest, I have no problem with that skew 3-pole motor with rare earth magnets, but some people seem to be hung up on the "3-pole" thing. I'm curious about what you think of that motor.
I also wonder if the "new" driver bearings will be prone to dislodging from their seats in the chassis, like the GS4 redesigned replacement drivers did (that Kato sold to replace the cracking-prone original drivers). Max Magliaro developed a styrene insert to prevent that from occuruing.
I never noticed an issue with the motor personally. Out of all of the shortcomings I ever saw with the model, the motor wasn't one of them.
As for the units that the bearings slip out of (only seems to be on the 4th (rear) driver, the fix I was using...take a round plastic swizel stick, cut a small chunk, slice down one side and insert over the driver axle between the bearings making sure there is a bit of play. Install in model and viola. Same idea as a styrene insert...it kept the bearings from slipping out of place.
Enjoy!
Kelley.
www.dufordmodelworks.com
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Thanks Kelley! That swizzle stick ideal is simple and clever.
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Kelley, how do you program the same ESU sound file on multiple locos?
Is it one at a time or do you have a trick?
When I do one it takes ages on LokProgammer.
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Kelley, how do you program the same ESU sound file on multiple locos?
Is it one at a time or do you have a trick?
When I do one it takes ages on LokProgammer.
Two ways....
1. I have an ESU production server gang programmer. If it's on their production server, I can load up to 8 decoders with the same file at a time (mine has issues and can only do 4 at a time). This really only works with OEM files as most retail files arn't on there. I usually end up having to rewrite the decoder data on a lokprogrammer once these are installed as changes get made anyways. (granted, once set up, that only takes like 30 seconds).
2. Alligator clips to a lokprogrammer. I'm constantly loading decoders, hitting start and walking away. Since something like the GS4 sound file isn't on the production server, I just use this approach.
There is no magical approach to make these things program faster. The trick is just to hit write file and walk away and go do something else. (not difficult for me....I'm usually working on 12 things at once).
Number 1 is a moot point to most people as they're generally not burning through thousands of decoders and it would have limited utility for one. Outside of an OEM or production type setting they're not available anyways.
So...alligator clip leads to your lokprogammer. You only need track input (red, black) to physically program a decoder. To test it is obviously another story.
Enjoy!
Kelley.
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Kelley, Thanks for the insight.
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but some people seem to be hung up on the "3-pole" thing.
I spent a fair chunk of my childhood watching trains start at one of the largest coal classification yards in the world (Williamson, WV), so my expectations are probably a little higher than average.
You show me a motor that can start my train slowly and smoothly - I'll buy it! :D
(if the 3-pole motor is so great, why is Kato wasting time and money developing a new motor? :trollface:)
Mark
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You show me a motor that can start my train slowly and smoothly - I'll buy it! :D
In my experience, with the PWM and BEMF motor drive of any DCC decoder (or even in DC with a good quality pulse throttle) you can have any motor (3-, 4-, 5-, 6-, or even 20-pole :D ) start smoothly, and run at very low rpms. Really.
(if the 3-pole motor is so great, why is Kato wasting time and money developing a new motor? :trollface:)
Easy, because they are innovators, and always striving to invent a better mouse trap. Just look at the evolution of their mechanisms.
It has nothing to do with how many poles motor has. IIRC, since their entry into N scale Kato used variations of straight-wound 5 pole motors. Modelers complained that it should be skew-wound, but that motor performs well, even being straight-wound.
Then they produced that small highly skewed 3-pole motor with very strong rare earth magnets. That 3-pole motor is rather new in the Kato motor evolution timeline. They probably produced that motor because they needed a smaller motor. But that doesn't mean they made step backwards. It was just a sideways move. That motor is still of "Kato quality". If the new slotless Kato motor only has 3 windings, will you automatically turn your nose at it?
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In my experience, with the PWM and BEMF motor drive of any DCC decoder (or even in DC with a good quality pulse throttle) you can have any motor (3-, 4-, 5-, 6-, or even 20-pole :D ) start smoothly, and run at very low rpms. Really.
So we're back around the block again. :D Too bad we can't meet in person to discuss this. For now we have to (again) agree to disagree. It may simply be that what you consider acceptable is unacceptable to me. Cheers!
(I don't appreciate being ridiculed though. Really. ;))
If the new slotless Kato motor only has 3 windings, will you automatically turn your nose at it?
Probably :trollface: But honestly - no. Not until I have witnessed first hand the performance (actual experience drives my opinion here).
Mark
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(I don't appreciate being ridiculed though. Really. ;))
Sorry if that's how it came out.
No names were mentioned, and you are far from being the only person automatically dismissing 3-pole motors. Yes, I too would welcome discussing this in-person, including some hands-on demonstrations.
Would it be possible for you to mention some specific loco (or locos) that has a 3-pole motor which soured you to 3-pole motors? If I own those models, I would like to see if I can also notice their inferiority. By the same token, which 5-pole equipped locos provide acceptable performance? Are you running DC or DCC? What brand throttle (DC) or brand of decoders (DCC) Give me some specifics. I like to see what you see.
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Sorry if that's how it came out.
Accepted. :D
Would it be possible for you to mention some specific loco (or locos) that has a 3-pole motor which soured you to 3-pole motors?
Short answer: all of 'em!. We've been around the block on that topic over the years as well, so no. ;)
I am slowly (and I do mean sloooooooooowly) coverting to DCC (I have a NCC Power Cab).
My philosophy on adding DCC to any model is to first make sure that the model performs well in DC (I have a 21st century MRC Tech zillion). That way, I know that if the model runs "funny" after installing DCC - I can at least rule out any problems with the mechanism.
As I already mentioned (many many times), I am ultra picky about slow speed performance - it just destroys the illusion for me.
It is possible that the GS-4 I witnessed was a "bad apple", so I am actually considering putting my money where my mouth is and picking up one of the new run GS-4s to see if it also fails my test (I really do like the proto very much!). Even if I am unhappy with the newest 3 banger, I would still have the prospect of "dropping in" the forthcoming "superior" motor. :D
Mark
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My philosophy on adding DCC to any model is to first make sure that the model performs well in DC (I have a 21st century MRC Tech zillion). That way, I know that if the model runs "funny" after installing DCC - I can at least rule out any problems with the mechanism.
As I already mentioned (many many times), I am ultra picky about slow speed performance - it just destroys the illusion for me.
Mark
I completely agree with you... I test all the mechanisms I custom build on DC first. If it doesn't run flawlessly, I tweak or rebuild it until it does. Only then will I put a DCC decoder on it.
DCC is not a cure-all... But really good running mechanisms run better on DCC (with the right decoder at least).
I'm with you on being ultra-picky with slow speed performance. Most commercial "steam" mechanisms fall short.
On motors... Coreless or five-pole iron core are all I'll bother with (and they have to be good quality iron core motors). But that doesn't mean that a 3 pole motor won't run well. If Kato is making a three pole, there's got to be something good about it.
Jeff
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Short answer: all of 'em!. We've been around the block on that topic over the years as well, so no. ;)
Well, the thing is that there aren't many locos produced in the last 20 (or even 30) years that use 3-pole motors. Maybe some Bachmann "white box" locos still used those, but those had terrible mechanisms, so the poor running could not be contributed to the motor. Of course the early N scale stuff from the '70s had 3-pole motors, but the mechanisms were last rather rough.
Maybe I should have asked you which locos with 5-pole motors perform acceptably to you. Again, it is not just the motor -- the mechanism design plays a major role in slow speed performance. Since you didn't give me any specific examples, could you provide some specific examples of the locos you find acceptable?
I am slowly (and I do mean sloooooooooowly) coverting to DCC (I have a NCC Power Cab).
My philosophy on adding DCC to any model is to first make sure that the model performs well in DC (I have a 21st century MRC Tech zillion). That way, I know that if the model runs "funny" after installing DCC - I can at least rule out any problems with the mechanism.
So that MRC Tech zillion gives you acceptable starts and slow speed with the 5-pole equipped locos? Could you mention the specific model number of your throttle (There is no MRC Tech zillion throttle). :-)
I agree 100% that the model should perform as well as possible in DC, so it will run just as well, or better with a quality decoder installed. But sometimes you just want some loco that due to its design is not quite as good in DC as you would like, and not much can be done mechanically to improve it. The PWM motor driver in the decoder will likely improve its slow speed running quality.
It is possible that the GS-4 I witnessed was a "bad apple", so I am actually considering putting my money where my mouth is and picking up one of the new run GS-4s to see if it also fails my test (I really do like the proto very much!). Even if I am unhappy with the newest 3 banger, I would still have the prospect of "dropping in" the forthcoming "superior" motor. :D
I do hope that you do pick one of those up and have a go at it.
Another thing I want to mention is that the number of poles is just a part of what contributes to the motor's overall perormance. JUst as important are other parts of motor's design.
(https://www.therailwire.net/forum/gallery/16/2700-190420044321-167242295.jpeg)
Case in point, the old Life-Like/Mehano 5-pole motor. Tes, it is a 5-pole motor, but it has very weak magnet mounted at the end of the motor, with iron plates as the motor's magnetic poles. It also has a fairly large air gap between the poles and armature. Die to all that, even with 5-poles, the motor sucks! It has almost no torque (read: poor low speed performance), and because of that low torque, it needed rather high voltage to get the loco running at a satisfactory speed. The armature was also wound with very thin wire (high resistance). All those factors woudl contribute to it running hot, and is sometimes literally burn up (the windings fried).
The crappy motor in the above photo has been modified by me, It was in a loco I donated to Lee and his retro layout. The only thing I did was to remove the weak magnets and replace them with more modern very strong rare earth magnets. The stronger magnetic field (even with the large gap at the armature) had noticeably improved its torque (and overall running quality). Still nowhere as good as any modern motors, but better than the original.
As you can see, the number of poles is just a small factor determining the quality of a motor.
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Well, the thing is that there aren't many locos produced in the last 20 (or even 30) years that use 3-pole motors.
Thank God! :D
Maybe I should have asked you which locos with 5-pole motors perform acceptably to you.
I have roughly 75 locos, not going there. :D (I gotta go to work)
Again, it is not just the motor -- the mechanism design plays a major role in slow speed performance.
No kidding! 8)
So that MRC Tech zillion gives you acceptable starts and slow speed with the 5-pole equipped locos? Could you mention the specific model number of your throttle (There is no MRC Tech zillion throttle). :-)
Yeah, I'm at home now - Tech 220. 8)
I agree 100% that the model should perform as well as possible in DC, so it will run just as well, or better with a quality decoder installed.
We probably agree on many things! :D
<snip> old Life-Like/Mehano 5-pole motor. Tes, it is a 5-pole motor, but it has very weak magnet mounted at the end of the motor, with iron plates as the motor's magnetic poles. It also has a fairly large air gap between the poles and armature. Die to all that, even with 5-poles, the motor sucks! It has almost no torque (read: poor low speed performance), and because of that low torque, it needed rather high voltage to get the loco running at a satisfactory speed.
While I agree that the Mehano motors were junk, I found them to give decent low speed performance. Here is a video of a MRC RSD15 mechanism that I stretched out over 40 years for a C630 project (that I never finished):
Note that this has been sitting in my junk box for decades and the "idler" wheels are dragging. :D
Off to work I go!
Mark
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While I agree that the Mehano motors were junk, I found them to give decent low speed performance. Here is a video of a MRC RSD15 mechanism that I stretched out over 40 years for a C630 project (that I never finished):
Note that this has been sitting in my junk box for decades and the "idler" wheels are dragging. :D
Off to work I go!
Mark
That is pretty good Mark, I assume that it is running using pulse DC power from your throttle ( IMO it would be impossible to get that crappy motor to run that slow with pure DC). BTW, most (if not all) 3-pole motors can be made to run that slowly using pulse DC throttle, or a DCC decoder with a PWM motor drive. Of course the rest of the mechanism cannot have any hitches.
And I see that you again danced around the subject instead of giving me some specifics on the 5-pole motor models which give you acceptable results. Even with hundreds of locos, could you give me one or 2 specific examples? And are those models unmodified, or you have done some tuning of the mechanism?
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Late to the fire....I had some fun arguments with Victor over 3 pole / 5 pole back in the day of the Atlas forums.
I for one am not totally against 3 pole motors if designed properly with a skewed armature...that said, the GS4 3 pole motor sucks. I have had to replace 4 of them so far in club members loco's, all due to one pole failing. I fought with my GS4 for a year, replacing decoders and and everything else before I realized it was a bad segment on the armature, and I should have known better. I just refused to believe it was the motor. After figuring mine out, I started seeing them fail in our Ntrak club. My GS4 is now on it's 3rd motor, the one I just took out had a magnet come apart. The armature is fine, the magnet got the equivalent of zamacitis and started swelling and eventually rubbed the armature. I wish I had another option for the loco.
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Late to the fire....I had some fun arguments with Victor over 3 pole / 5 pole back in the day of the Atlas forums.
I for one am not totally against 3 pole motors if designed properly with a skewed armature...that said, the GS4 3 pole motor sucks. I have had to replace 4 of them so far in club members loco's, all due to one pole failing.
So we are back to square one. The Kato's 3-pole motor's performance (slow speed or otherwise) is not problematic at all -- the problem is mechanical or electric failures.
I had a Kato 5-pole motor with the same exact problem. Kato just crimps the wire into the commutator tab to make electrical connection. No solder. Well, they solder on the ceramic ring after the wires are crimped. The crimping force breaks through the enamel on the wire, creating electrical connection. In my example, that connection failed. Just to see if I can fix it, I took the motor apart, gently scraped the enamel from the wire a and soldered it to the commutator tab. Arrow shows the extra solder. That fixed the motor.
(https://www.therailwire.net/forum/gallery/13/2700-211019172330-130871685.jpeg)
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While I agree that the Mehano motors were junk, I found them to give decent low speed performance. Here is a video of a MRC RSD15 mechanism that I stretched out over 40 years for a C630 project (that I never finished):
Note that this has been sitting in my junk box for decades and the "idler" wheels are dragging. :D
Mark
Having dealt with many old mechanisms.... that video is impressive to me.
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@Mark5
I see you visited the forum couple of days ago.
Throughout our 3-pole motors suck exchange in this thread I have asked you to provide some specific examples of 3-pole equipped locos you find inferior, and you pussyfooted around the subject. Fine. So, on Jan. 5th I asked you to maybe give me some examples of 5-pole equipped locos you find satisfactory (as far as slow speed goes), and that request was again met with silence. I'm beginning to think that you are full of it (not disrespect meant, but what else should I think?). It only takes couple of minutes of typing to provide some examples I asked for.
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Wow, this is an interesting thread. I am guessing we (model railroaders) are looking for a motor that has a very smooth starting .
Are we attacking this from the right end (MOTOR)?
To get a motor running we must apply enough voltage to over come the static friction.
We keep on upping the volts until the moment to motor starts to turn- static friction no longer applies, it is now kinetic friction.
Once the static friction is gone we now need much lower volts to keep it running.
This is what PWM does-it apples spikes of volts to try to kick the motor to turn. Once that happens we really do not need PWM, do we?
Maybe we need to use a gear box reduction so the motor uses high rpm’s .
Just a thought? Like 500 to 1 ?
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I think the problem with Kato is they have like no gear reduction in their locomotives. Just make it move and stop there. Add gear reduction and just about any motor will preform better. The motors will still be running fast, but the locomotives will be slow.
With Kato's excellent manufacturing abilities they should work on their own 4:1 (or 3:1, 2:1) gearhead to fit their motors and now worry about the motor.
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Wow, this is an interesting thread. I am guessing we (model railroaders) are looking for a motor that has a very smooth starting .
Are we attacking this from the right end (MOTOR)?
Yes a very smooth start, smooth slow speed, and realistic (not extremely excessive) top speed are all highly desired features for model locomotives). Motor is only one part of the equation. The rest of the mechanism (including the gear ratio), including overall low-friction design all play important roles in how the model runs.
To get a motor running we must apply enough voltage to over come the static friction.
We keep on upping the volts until the moment to motor starts to turn- static friction no longer applies, it is now kinetic friction.
Once the static friction is gone we now need much lower volts to keep it running.
That's pretty close to what's going on. But if done as you described, it would cause the model to lurch before the voltage can be lowered. Plus, at very slow motor rpms, it produces very little torque (inherent to the motor's design), so unless the mechanism is very low friction, the model could easily stall again.
This is what PWM does-it apples spikes of volts to try to kick the motor to turn. Once that happens we really do not need PWM, do we?
Maybe we need to use a gear box reduction so the motor uses high rpm’s .
You are confusing PWM and "pulsed DC". PWM is a method to produce a variable (zero-to-full) average voltage using variable width pulses of full voltage. This method is universally used in the motor driver circuit of DCC decoders because it is very efficient, so the small surface-mount motor-driver transistors on the decoder do not have to dissipate much heat. They act like switches - either full on or full off (so they do not have to act like variable resistors dissipating whatever power is not delivered to the motor).
The frequency of those PWM pulses is too high to have a kick-like effect on the motor's armature. Those "kicks" have to lower frequency to have desired effect on the armature. But conveniently, the same circuitry used for PWM motor power can also be utilized for the "kicks". The microcontroller on the decoder (or electronics in a PWM throttle) can modify the PWM pulse duration to produce those "kicks". The same motor-driver circuitry also measures the BEMF voltage generated by the motor using it as feedback indicating the motor's rpms, and adjusts the PWM signal appropriately to keep the motor running smoothly.
In a simple old-school pulse capable throttles, the normal variable DC voltage was actually 120Hz full-wave rectified voltage coming from the transformer inside the throttle. If pulse feature was turned on, it changed the output voltage to half-wave rectified DC. That created the pulses needed for kicking the motor's armature. It was fairly crude, but effective. There was no BEMF feedback.
Just a thought? Like 500 to 1 ?
Well, that kind of gearing would produce extremely smooth start and slow speed, but even with full throttle the model could only achieve probably 2 scale MPH. Kind of like if your car was stuck in first gear (well actually more like in a 0.1 gear - much slower than first gear). But you are right, Numerically higher gear ratios trade rpms for torque, and the more torque is available, the smoother the model will run.
But many of the N scale locos are geared numerically too low. Basically they have excessive top speed, which also makes them poor performers when it comes to smooth starts and smooth low speed, as there is very little torque available at low speeds. That would be like trying to gently start your car in 3rd gear and trying to maintain smooth slow-speed running. That's all without being able to use the variable friction clutch - the motor would be solidly connected to the gearbox, since we have no clutches in our models. These are extreme examples, but demonstrate the idea.
The best solution IMO would be to have the models geared in a way which would result in a top speed similar to the prototype speed. Well a bit higher, since many modelers would consider prototypical top speeds too slow for operating on a layout (especially NTRAK layout :D ). I know, I'm an NTRAK member. That, plus a good quality motor (like a coreless motor with plenty of torque) would make our models run well on slow speeds,. Of course lets not forget the low-friction mechanism. With all those things there would be very little need for "kicking" the motor's armature.
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Wow, this is an interesting thread. I am guessing we (model railroaders) are looking for a motor that has a very smooth starting .
Are we attacking this from the right end (MOTOR)?
To get a motor running we must apply enough voltage to over come the static friction.
We keep on upping the volts until the moment to motor starts to turn- static friction no longer applies, it is now kinetic friction.
Once the static friction is gone we now need much lower volts to keep it running.
This is what PWM does-it apples spikes of volts to try to kick the motor to turn. Once that happens we really do not need PWM, do we?
Maybe we need to use a gear box reduction so the motor uses high rpm’s .
Just a thought? Like 500 to 1 ?
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I just remove the high speed Kato motor and install a scale speed Atlas motor. Problem solved!
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Opps, looks like I did a double post—SORRY. !
Pete, on the over coming of friction, is that not what is happening. We apply voltage until motor starts to turn, now there is no way that I can see that we can lower the volts before the motor is over speed and the loco takes off like a rocket.
So.what ever controler we are using it is try’s to keep the motor running while at the same time trying not to apply too many volts.
Back when I used DC I built several throttles that had a (what was called PWM) at least that Is what I recall, built into the throttle. You could change the pulse rate has you ran the loco. You could hear the sweet spot while running.
No BEMF for sure
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Pete, on the over coming of friction, is that not what is happening. We apply voltage until motor starts to turn, now there is no way that I can see that we can lower the volts before the motor is over speed and the loco takes off like a rocket.
So.what ever controler we are using it is try’s to keep the motor running while at the same time trying not to apply too many volts.
Yes, that's basically it. Main problem is the very low torque generated by the motor at low voltage, low rpms. Pulsing the DC voltage (using full 12V) gives the armature the "kick" needed to keep spinning and overcoming any hitches in the mechanism.
Back when I used DC I built several throttles that had a (what was called PWM) at least that Is what I recall, built into the throttle. You could change the pulse rate has you ran the loco. You could hear the sweet spot while running.
No BEMF for sure
Yes, I built a throttle like that too (TAT V throttle I housed in a modified old MRC throttle case), and I could control the pulse frequency, duration and few more parameters. It can make the loco run really smoothly.
(https://www.therailwire.net/forum/gallery/16/2700-160420201108-166221503.jpeg)
While those pulses are a type of Pulse Width Modulation, like I explained earlier, it is different than the higher frequency PWM a DCC decoder uses to vary the motor voltage. That type of PWM is described in https://en.wikipedia.org/wiki/Pulse-width_modulation (https://en.wikipedia.org/wiki/Pulse-width_modulation). This type of PWM is not uses to "kick" the armature, but to provide a variable voltage to run the motor.
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Wow, that is some deep reading!!
I do not think we can come up with a good gearing solution action for are locomotives.
How about a fluid coupling. I read something about that some time ago. Do not recall where.
But that would let the motor ramp up and we would see a very slow output. Too fast or slow, change the viscosity of the fluid.
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Wow, that is some deep reading!!
I do not think we can come up with a good gearing solution action for are locomotives.
How about a fluid coupling. I read something about that some time ago. Do not recall where.
But that would let the motor ramp up and we would see a very slow output. Too fast or slow, change the viscosity of the fluid.
The thing is that there are combinations of low-friction mechanism design, gearing ratio, and motors with appropriately ample torque (even at low speed) that perfection can be achieved. Just ask Mark - he is fussy about smooth low speed, and he seems to have found such combination (but he is keeping it a secret for now :( ).
Fluid coupling? Yes, that is exactly what replaces the dry clutch in cars with automatic transmissions: Torque converter. Interesting idea, but I think that just like mass, viscosity does not scale. I could be wrong, but either way, that could get messy. :)
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Well yes & no. A fluid coupling has only three elements. Where a toque converter has three also but one being a stator.
The fluid coupling has a driven pump and a drive pump contained with a housing. No stator used.
There is no torque multiplying with the fluid coupling. With the torque converter the stator redirects the fluid to get more torque.
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Well yes & no. A fluid coupling has only three elements. Where a toque converter has three also but one being a stator.
The fluid coupling has a driven pump and a drive pump contained with a housing. No stator used.
There is no torque multiplying with the fluid coupling. With the torque converter the stator redirects the fluid to get more torque.
Similar idea though. Likely not feasible for N scale, and how would it handle a loco pulling a long train (not running light)? Anyway, I don't believe we'll see a fluid coupling in N scale locos in the immediate future.
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@Mark5
I see you visited the forum couple of days ago.
OK, I have been VERY busy this month with real life stuff. It's been a few weeks since I've been on the forum - at last I have to time to sit down and do fun stuff and I come back to see this ... :facepalm:
Throughout our 3-pole motors suck exchange in this thread I have asked you to provide some specific examples of 3-pole equipped locos you find inferior, and you pussyfooted around the subject. Fine. So, on Jan. 5th I asked you to maybe give me some examples of 5-pole equipped locos you find satisfactory (as far as slow speed goes), and that request was again met with silence.
Pete, we've been around the block on this topic many times over the years - it gets tiresome repeating myself. A few examples:
I've seen the bmann and kato 3 polers cog.
I have not yet witnessed the wonder in the MP15.
Of the Bachmann locos I own I have four Bachmann locos with 3 pole motors: 2 N&W "J"s, 1 2-6-6-2, and one FM H16-44. The "modern" 3 pole motors perform well in slow speeds, but with that "stutter" that only I seem to have the "gift" to see. :P
I have one of the 4-6-2s. The tender pickup was stupid (1970s style). Not a biggie as the loco I plan to build needs a USRA long hand me down tender. The Bachmann USRA long with its excellent pickup solved that prob.
Test runs were pretty good - the gearing must be good as it was able to run smoothly at low speeds, even with the crappy 3 pole motor.
Mark
Subsequent to these posts I am quoting above, I took a sabbatical from my "real" career for a few years and worked full time in customer service at MBK - this afforded me ample time to test run all sorts of locos.
I'm beginning to think that you are full of it (not disrespect meant, but what else should I think?). It only takes couple of minutes of typing to provide some examples I asked for.
"not disrespect meant" - in the the middle of what I can only take as thinly veiled insult. :facepalm: Is this forum moderated? :trollface:
I don't understand your hostility to folks that don't care for these motors. I have come to the conclusion that you and I have different ideas about what we consider to be acceptable low speed performance.
I came into this thread because the prospect of a better motor from Kato that might fit the GS4 excited me ... alas now I think I might to need to take a break from the railwire. :RUEffinKiddingMe:
Mark
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I don't understand your hostility to folks that don't care for these motors.
I believe you are confusing hostility with curiosity. If I held some positive or negative opinion about something, and I was asked to present more specific details about on what I base my opinions on, I would gladly provide those.
I am sorry if I offended you Mark, but your refusal to provide some specific examples of acceptable and unacceptable models (as far as slow speed is concerned) was really very surprising to me. Looks ike the older posts you quoted give me some insight to your experiences. Thanks!