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Offline tulit  
#1 Posted : 19 October 2017 19:45:03(UTC)
tulit

Canada   
Joined: 20/05/2012(UTC)
Posts: 400
I really wish we could still buy the C-sine SDS driven locomotives for their general quietness and smoothness.

For the past few years there's been the rail4you.ch product but it seems overally expensive and not sure if it is/ever will actually become available.

With the advent of small RC models over the past few years, there's been a introduction of a lot of small, low cost brushless solutions.

I decided to see if I could start on a project to make use of these and see if I could convert a old locomotive with a standard DCM motor into a brushless drive system.


Here you can see a sample of a motor itself, a 3 phase brushless outrunner. This is a motor designed to run at 2S (7.4V) peak. The one potential draw back of it is that it's 5200kv which is a fairly fast spinning motor. Something more on the order of 700kv would be better suited, but this what was quickly available for now to try with. Worse case one could go down the road of attempting to rewind this motor. I may have gone slightly too small with this choice, but it still has a fair amount of torque and there's plenty of other options available to try with.



Here's a comparison and you can get a feel for how small it really is.



The motor itself fits well within the available space



One of the first hurdles will be building a new motor plate to hold it in place. If anyone has 3D mechanical modelling experience and wants to help out here that would be great. I have access to 3D printing FDM and CNC at home and full SLA printers at work to build the prototypes.


As for the electronics side, most of what is needed is easily handled in the RC market as well. My idea for now is to use as many off-the-shelf components as possible with the ultimate goal of consolidating them on a integrated PCB once it's proven out.


From left to right:

1) 5V buck converter (voltage regulator). This will supply all power to each item downstream. Ahead of it will be a simple AC/DC rectifier/filter from our track voltage.
2) The motor again
3) The ESC (electronic speed controller). This takes a standard server input signal (sort of PWM but not quite) and drives the 3 phases of the motor appropriately. Since this is off the shelf, it's unidirectional but the integrated one could easily have reversing ability.
4) The last is a small micro. It's main purpose will be to sample the motor voltage output from the existing decoders motor leads in the locomotive and convert it to the pulse train necessary to control the speed on the ESC. It will have to be prefaced with a small amplifier to circuit to apply a DC offset and scaling. This way we can easily retrofit/integrate with existing decoders.



You're looking at a total cost of components of only around $25 in this picture. Cost will come down further with a integrated PCB.



Ill try and update as I progress and share how things proceed. Again, if someone can assist in the 3D modelling area that would be very helpful.

Edited by user 19 October 2017 23:54:36(UTC)  | Reason: Not specified

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Offline dominator  
#2 Posted : 19 October 2017 22:19:46(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 734
Location: Kerikeri
Interesting. Please keep us informed. I have a few loco's which should run quietly but the motor noise is too loud. I'm not an electrical nut so dont know what you mean by the 5200kva compared to 700kva means apart from presuming the 700 runs at 13% of the speed of the 5200. What is the speed of a regular DCM or FCM motor in comparison. Would that high torque 5200 moter be able to happily run slow enough in our engines, presuming the highest output could be controll by the digital electronics, or would a step down gearbox need to be designed for it.
Dereck
Northland. NZ REMEMBER 0228 for ä
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Offline Minok  
#3 Posted : 19 October 2017 23:58:54(UTC)
Minok

United States   
Joined: 15/10/2006(UTC)
Posts: 1,993
Location: Washington, Pacific Northwest
Originally Posted by: dominator Go to Quoted Post
I'm not an electrical nut so dont know what you mean by the 5200kva compared to 700kva means apart from presuming the 700 runs at 13% of the speed of the 5200.
Dereck


kva = kilo volt ampers = volts * amps = power (watts) in a general sense.

Electrical power in - friction and heat losses => produces mechanical power out.

So more kva mean more power out. How that power is used can be more torque or faster rotation, depending on the design.

This will be a cool project to follow and I'm hoping for the best.

Edited by moderator 29 April 2019 21:04:21(UTC)  | Reason: Fixed quoting error

Toys of tin and wood rule!
---
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Offline applor  
#4 Posted : 20 October 2017 05:50:37(UTC)
applor

Australia   
Joined: 21/05/2004(UTC)
Posts: 1,370
Location: Brisbane, Queensland
I am very interested in this as well and keen to see the difference in noise after the conversion.

If there is a good improvement and the price is reasonable, I can see myself and many others converting their DCM loks.
modelling 1954 Germany (era IIIa)
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Online kiwiAlan  
#5 Posted : 20 October 2017 12:13:37(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 4,398
Location: ENGLAND, Didcot
Originally Posted by: tulit Go to Quoted Post

I decided to see if I could start on a project to make use of these and see if I could convert a old locomotive with a standard DCM motor into a brushless drive system.


Interesting idea. I like your thinking. ThumpUp

Originally Posted by: tulit Go to Quoted Post

Here you can see a sample of a motor itself, a 3 phase brushless outrunner. This is a motor designed to run at 2S (7.4V) peak. The one potential draw back of it is that it's 5200kv which is a fairly fast spinning motor. Something more on the order of 700kv would be better suited, but this what was quickly available for now to try with. Worse case one could go down the road of attempting to rewind this motor. I may have gone slightly too small with this choice, but it still has a fair amount of torque and there's plenty of other options available to try with.


I don't know what you mean by 2S (7.4V) - or is that the number of battery cells? It sounds like it might be at that voltage.

I presume when you say 5300kv that you mean 5200 revs per minute, which would make sense for a motor of about this size.

I suspect this motor has built in electronics judging by it having only three wires. This will mean it will run at only one speed (two speeds if you count STOP). It will need external electronics the way the C-Sine motor has to make it variable speed. This would be a significant project for someone skilled in electronics to get it running smooth and as good as a C-Sine motor.

As an aside to this, what do you suggest doing to put a suitable gear on the motor shaft to engage with the drive train?

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Offline tulit  
#6 Posted : 20 October 2017 13:12:37(UTC)
tulit

Canada   
Joined: 20/05/2012(UTC)
Posts: 400
Originally Posted by: kiwiAlan Go to Quoted Post
Originally Posted by: tulit Go to Quoted Post

I decided to see if I could start on a project to make use of these and see if I could convert a old locomotive with a standard DCM motor into a brushless drive system.


Interesting idea. I like your thinking. ThumpUp

Originally Posted by: tulit Go to Quoted Post

Here you can see a sample of a motor itself, a 3 phase brushless outrunner. This is a motor designed to run at 2S (7.4V) peak. The one potential draw back of it is that it's 5200kv which is a fairly fast spinning motor. Something more on the order of 700kv would be better suited, but this what was quickly available for now to try with. Worse case one could go down the road of attempting to rewind this motor. I may have gone slightly too small with this choice, but it still has a fair amount of torque and there's plenty of other options available to try with.


I don't know what you mean by 2S (7.4V) - or is that the number of battery cells? It sounds like it might be at that voltage.

I presume when you say 5300kv that you mean 5200 revs per minute, which would make sense for a motor of about this size.

I suspect this motor has built in electronics judging by it having only three wires. This will mean it will run at only one speed (two speeds if you count STOP). It will need external electronics the way the C-Sine motor has to make it variable speed. This would be a significant project for someone skilled in electronics to get it running smooth and as good as a C-Sine motor.

As an aside to this, what do you suggest doing to put a suitable gear on the motor shaft to engage with the drive train?



Hi.

No, 2S is common terminology in the battery world. Here is means 2 cells in series (each cell being 3.7v).

KV is common terminology in the motor world. Here it means RPM/V under NO load. It’s hard to extrapolate to real world as there is always a load and tends to be significantly slower. The DCM gearbox provides further reduction. Hence though my guesstimate something closer to 700KV would be more ideal to run all the way from 0-7.4V

And no, the motor has no electronics. It’s a 3 phase brushless motor hence 3 leads. You vary the speed by adjusting the frequency/amplitude of the drive. The ESC shown are the drive electronics (basically a small 3 phase inverter). Direction is easily changed by swapping two lead so the phase ordering reversed.

The gear is a simple 7 tooth spur. It’s easy to find premade brass ones, remove one from a existing marklin rotor, cut my own or even possibly 3D print one. The shaft sizes between my motor and the marklin one are the same.
Offline Webmaster  
#7 Posted : 20 October 2017 20:39:55(UTC)
Webmaster


Joined: 25/07/2001(UTC)
Posts: 10,830
I've also looked at these kind of motors as replacements...

If I get it right with my limited understanding of the semantics in the RC motor world... They are also used in "drones" as I understand...
Would a "4S" (about 14-15V) be a direct replacement for a Märklin motor if you don't want to make special driver boards and such?
If it's small enough, of course... I suspect that 14-15V motors are bigger...

Or something like this?
https://www.aliexpress.c...2394072_32740560757.html
Juhan - "Webmaster", at your service...
He who asks a question is a fool for five minutes. He who does not ask a question remains a fool forever. [Old Chinese Proverb]
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Offline tulit  
#8 Posted : 20 October 2017 21:18:39(UTC)
tulit

Canada   
Joined: 20/05/2012(UTC)
Posts: 400
Originally Posted by: Webmaster Go to Quoted Post
I've also looked at these kind of motors as replacements...

If I get it right with my limited understanding of the semantics in the RC motor world... They are also used in "drones" as I understand...
Would a "4S" (about 14-15V) be a direct replacement for a Märklin motor if you don't want to make special driver boards and such?
If it's small enough, of course... I suspect that 14-15V motors are bigger...

Or something like this?
https://www.aliexpress.c...2394072_32740560757.html


No you'll need the electronics to covert either the 1 phase AC (of say analogue operation) or the DC to three phase as these are in-fact 3phase AC motors.

Offline Minok  
#9 Posted : 20 October 2017 21:31:34(UTC)
Minok

United States   
Joined: 15/10/2006(UTC)
Posts: 1,993
Location: Washington, Pacific Northwest
Ah, right so I was Waaaaay off base. Stupid overloaded terms.

KV is really Kv (best we can do without subscripts)...

THe value represents how many RPM the motor spins at 1V applied. So at 2V it would spin faster.

https://en.wikipedia.org/wiki/Motor_constants

Toys of tin and wood rule!
---
My Layout Thread on marklin-users.net: InterCity 1-3-4
My YouTube Channel: https://www.youtube.com/user/Minok1217/
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Offline dominator  
#10 Posted : 21 October 2017 01:13:07(UTC)
dominator

New Zealand   
Joined: 20/01/2015(UTC)
Posts: 734
Location: Kerikeri
Keep up the good work here. This is looking interesting.
Northland. NZ REMEMBER 0228 for ä
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Offline tulit  
#11 Posted : 21 October 2017 01:24:45(UTC)
tulit

Canada   
Joined: 20/05/2012(UTC)
Posts: 400
Was actually able to get a very quick prototype motor plate printed up. The CAD model definitely needs work but a quick check to see how things might fit together. I can still probably clean this up a lot on the mill if it isn't a perfect fit.



The print is still curing (and so a bit wet still)
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Offline river6109  
#12 Posted : 21 October 2017 02:05:02(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 12,498
Location: On 1965 Märklin Boulevard just around from Roco Square
Hi all, you may get a quieter motor but you're loosing a lot of weight, I admire those who try and it always amazes me why manufacturers don't go down that path., furthermore a small motor like this, who says 2 couldn't be installed but I like the idea whereas a motor is driving the bogies via cardan shaft and the rest of the loco frame can be filled in with metal, like most of the Traxx locos Märklin is producing, they could be fattened up with more weight.

Noise never bothered me that much but on older locos it definitely could do with an upgrade from 5 pole (60944, 60943) to a different drive system and I don't know whether or not I would ever go down that path.

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
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Offline mario54i  
#13 Posted : 21 October 2017 21:00:17(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 178
Location: Torino,
I see that these motors are very powerful, in the tens W range, and consequently currents are in the many A range.
Will the train take off ?
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Offline sudibarba  
#14 Posted : 22 October 2017 03:49:53(UTC)
sudibarba

United States   
Joined: 28/07/2006(UTC)
Posts: 873
Location: Augusta, GA USA
Don't get it. A lot of work for making a Marklin Lok into something it is not if it works.
I can barely keep my 100 loks running much less changing the motors out. I know mine
are not all the old style but I like them as they are. This hobby costs me enought as it is.

Eric
Offline tulit  
#15 Posted : 22 October 2017 14:28:50(UTC)
tulit

Canada   
Joined: 20/05/2012(UTC)
Posts: 400
Originally Posted by: mario54i Go to Quoted Post
I see that these motors are very powerful, in the tens W range, and consequently currents are in the many A range.
Will the train take off ?


Power is fairly well controlled with these. The motor will never be at 100%
Offline DaleSchultz  
#16 Posted : 29 April 2019 17:27:25(UTC)
DaleSchultz


Joined: 10/02/2006(UTC)
Posts: 3,046
any progress here?
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
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Offline lewistrain  
#17 Posted : 12 May 2019 21:58:57(UTC)
lewistrain

Australia   
Joined: 08/03/2016(UTC)
Posts: 68
Location: New South Wales, Sydney
He probably got scared off by he total lack of enthusiasm for what would be the best motor choice for model trains.
Its deffinatley on my list of future experiments.
LOLOLOL they are just toys, grow up and play with them.
Offline tiono  
#18 Posted : 13 May 2019 02:52:37(UTC)
tiono

United States   
Joined: 09/02/2010(UTC)
Posts: 224
or may be the experiment failed, because the replacement motor was not suitable.
The motor was designed to power a drone's propeller, high rpm low torque. While the locomotive need a low rpm high torque motor.
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Offline mario54i  
#19 Posted : 13 May 2019 11:56:46(UTC)
mario54i

Italy   
Joined: 28/03/2007(UTC)
Posts: 178
Location: Torino,
Maybe the right brushless motor for this application is a Maxon EC20 flat but it costs >100 €
A Märklin complete spare bogie with Csinus1 motor costs 160 €
Offline lewistrain  
#20 Posted : 13 May 2019 12:41:08(UTC)
lewistrain

Australia   
Joined: 08/03/2016(UTC)
Posts: 68
Location: New South Wales, Sydney
Originally Posted by: tiono Go to Quoted Post
or may be the experiment failed, because the replacement motor was not suitable.
The motor was designed to power a drone's propeller, high rpm low torque. While the locomotive need a low rpm high torque motor.


Possibly, but the motors are available in a dizzying array of speed ranges.
And the slow speed torque is mind bending.
These motors are made in china and cost far less than any maxon or c sinus to purchase, but will last far longer than either.
LOLOLOL they are just toys, grow up and play with them.
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Offline TEEWolf  
#21 Posted : 13 May 2019 23:23:37(UTC)
TEEWolf

Germany   
Joined: 01/06/2016(UTC)
Posts: 1,765
Originally Posted by: mario54i Go to Quoted Post
Maybe the right brushless motor for this application is a Maxon EC20 flat but it costs >100 €
A Märklin complete spare bogie with Csinus1 motor costs 160 €


Perhaps you look on this website as well.

https://www.sb-modellbau.com/#

For my BR 194 091-5 Märklin art #3022.03 they offer a brushless motor for 117 €.

https://www.sb-modellbau...satz-Maerklin-E-94_R-194
CS 3 is a controller system from Märklin - not a central station.
Offline Purellum  
#22 Posted : 14 May 2019 05:41:40(UTC)
Purellum

Denmark   
Joined: 08/11/2005(UTC)
Posts: 3,069
Location: Mullerup, 4200 Slagelse
Cool

Originally Posted by: TEEWolf Go to Quoted Post


Perhaps you look on this website as well.

https://www.sb-modellbau.com/#

For my BR 194 091-5 Märklin art #3022.03 they offer a brushless motor for 117 €.

https://www.sb-modellbau...satz-Maerklin-E-94_R-194


This is a DC micromotor from Faulhaber, not a brushless motor.

Per.

Cool

If you can dream it, you can do it!

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In case this is not legally possible:
I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

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