Thoughts on Motors

Model and prototype rolling stock, locos, multiple units etc.
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zebedeesknees
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Re: Thoughts on Motors

Postby zebedeesknees » Tue May 09, 2017 7:02 pm

jon price wrote:I keep looking at RC, and there is some interesting stuff out there, but until there is an alternative to LiPo batteries I won't try it. If you look seriously at the safety precautions advised by level headed commentators you wont try it, If only because melting those expensively created locos is bad for morale.And before anyone tells me that all you need is to do it properly, well "doing it properly" on the kind of custom rigs we will require is not going to be easy, and the less easy it is the more chance of failure.

"Charging Location. As you saw above, a LiPo charging fire likes to shoot flames in all directions. You should really try to charge your batteries in places where a flame like this will not catch your house on fire. If you have a garage or basement with concrete or brick walls, that’s a fantastic place. A bathtub without a shower curtain is another decent idea. Another excellent option is just on a driveway outside of your house."
http://www.propwashed.com/lipo-battery-charging-basics/


If you use a soldering iron, it gets very hot and could start a fire, or cause serious burns to skin; so could acid fluxes, the acid is nearly as strong as that in a fizzy drink. The fumes given off could damage lungs and eyes, even with resin fluxes. Some people even still use solder containing lead! Of course, Cyanoacrylate is an alternative, but that will adhere to skin very well, and could tear skin if pulled away too hard. Not only, but heat such as from a soldering iron on cyano causes it to give off very dangerous cyanide fumes. Then, most solvents used for making polystyrene kits contain, or are entirely Methyl Ethyl Ketone, a highly volatile liquid which evaporates into a gas with a flashpoint of -7 deg. C, any naked flame in the vicinity causes an explosion.

So.. H&S advise that you should NOT learn to make anything for yourself, it's much too dangerous...

Zeb.

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jon price
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Re: Thoughts on Motors

Postby jon price » Tue May 09, 2017 9:11 pm

The safety issues are not "H&S gone mad" problems. The issues you describe are the result of easily avoidable bad practice. With Lipo batteries it is often the case that you are dealing with a problem which you have little chance of recognising despite behaving sensibly. The advice on charging doesn't come from a safety manual, but from a guide for and by aircraft hobbyists.

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Flymo748
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Re: Thoughts on Motors

Postby Flymo748 » Tue May 09, 2017 9:43 pm

jon price wrote:The safety issues are not "H&S gone mad" problems. The issues you describe are the result of easily avoidable bad practice. With Lipo batteries it is often the case that you are dealing with a problem which you have little chance of recognising despite behaving sensibly. The advice on charging doesn't come from a safety manual, but from a guide for and by aircraft hobbyists.


Having been in the paddock at Silverstone in 2011 when one of the TTZero motorbikes spontaneously caught fire, I understand a certain element of circumspection.

From being treated with the small fire extinguishers which are always present when there is petrol and race bikes, to the full marshal's fire extinguishers, *everything* was emptied onto the blaze and still it burned.

We had to evacuate the immediate area and leave it to burn out. There was a blackened depression left in the tarmac afterwards, and the smouldering remains of a two hundred grand motorbike.

Once lithium batteries start to burn, run away very quickly!

Have a look at http://motorsport.photographybykevan.com/2011archive/bemsee_silverstone1/index.html

Cheers
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

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LesGros
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Re: Thoughts on Motors

Postby LesGros » Tue May 09, 2017 9:54 pm

Jon is right to sound a cautious note; a LiPo fire is not trivial.

A key point about the danger created by a LiPo fire, is that, like magnesium, it burns VERY HOT. There is nothing available in the home that can put it out; adding water (H2O) makes it worse. [you are adding Hydrogen and Oxygen to material at a temperature which can separate water into both to add to the ferocity of the burn].

The best you can do is be ready to put out the fire in the surrounds when the LIPo has burned itself out. Hence the advice in the r/c world to take great care and position your batteries in fire resistant place for charging.
LesG

The man who never made a mistake
never made anything useful

dal-t
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Re: Thoughts on Motors

Postby dal-t » Wed May 10, 2017 6:13 am

I agree a lithium ion fire is not a trivial event (dangerous air cargo rules have made that clear for some time), but if it's a bit smaller than a motorbike or Formula E car there are safety measures you can take. Specific lithium extinguishers are available, like this one, or you can arm yourself with one of these. Something for exhibition managers to consider if radio-control takes off, perhaps?
David L-T

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Jol Wilkinson
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Re: Thoughts on Motors

Postby Jol Wilkinson » Wed May 10, 2017 7:45 am

I refer you to Tim's opening post.

As usual we have wandered of into new territory without coming to terms with the issue that will affect many model makers, including those outside this Forum and Society. As Philip points out, the volume RTR manufacturers ares sourcing "traditional" twelve volt motors and for many that is still a technology they still wish to use.

While those pushing the current limits of available technology, whether for self satisfaction, kudos or commercial benefit, may consider using what we have been satisfied with for some years as old hat, etc. they should reflect that it may not be practical to adopt a second means of powering and controlling our models alongside our existing system, for a variety of reasons. Equally it may not be possible to re-engineer our existing models to take the new technology.

May I therefore suggest that those who wish to discuss/debate/praise/promote RC systems with battery power do so in a different thread.

The N20 motor that Nigel introduced still requires a right angle final drive as far as I can see to produce what many of us require. Modelling pre-group - and therefore smaller - locos provides a constraint on power train size that it has been possible to handle with our existing gear systems and a range of different size motors. This motor seems to have potential:

https://www.banggood.com/N20-DC12V-300R ... uytogether

although I haven't been able to find a source of final drive gears to suit. At 12mm wide it's also on or above the limit to use in OO frames, which is a commercial consideration for kit/motor mount suppliers.

Whichever voltage of motor we look at, we continue to be in the hands of what the manufacturers produce. None are made specifically, as far as I know, for model railway application. We were perhaps fortunate that Mr Mashima saw and exploited a niche market. The Mitsumi 12v appears to be the only suitable (size, power, etc.) "standard" motor available at the moment, but even that will not meet all 4mm modellers needs. So I think that, at the moment, we need to keep looking.

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jim s-w
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Re: Thoughts on Motors

Postby jim s-w » Wed May 10, 2017 7:47 am

zebedeesknees wrote:
So.. H&S advise that you should NOT learn to make anything for yourself, it's much too dangerous...

Zeb.


If only you blamed it all on the meddling EU too! The daily mail would have guaranteed you a job on that post alone! You probably would have lasted a few years too before they figured out you were being ironic! :D

Jim

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jon price
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Re: Thoughts on Motors

Postby jon price » Wed May 10, 2017 9:08 am

Referring back to Nigel Lawton's drive solution for micro 009 locos, as also proposed for DMUs the (smooth) drive from the mini motors (6v but running on 12V with a tiny resistor) he uses can be (are) easily and flexibly achieved with a friction belt. Before the cries of alarm go up this is a system used succesfully on the Harley Sturgis in the 80s. This is therefore a drive system which can handle torque and loads at a serious level. The band on a Harley Sturgis has teeth with a 14mm pitch, but reduced down to our scale they would (it seems to me) be little more than a rough surface, which is what you get with rubber. Perhaps our more engineering or motorcycle minded correspondants can comment?
https://www.denniskirk.com/s-and-s-cycl ... 020431.sku
The link is to a closer image of the drive belt
sturgis.jpg
sturgis.jpg (72.33 KiB) Viewed 6007 times

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Le Corbusier
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Re: Thoughts on Motors

Postby Le Corbusier » Wed May 10, 2017 9:33 am

Jol Wilkinson wrote:I refer you to Tim's opening post.

As usual we have wandered of into new territory without coming to terms with the issue that will affect many model makers, including those outside this Forum and Society. As Philip points out, the volume RTR manufacturers ares sourcing "traditional" twelve volt motors and for many that is still a technology they still wish to use.


Would it be possible to run different voltage motors on the same DC/DCC system by utilising some electronic wizardry? I say this because unless another manufacturer can be found who will prioritise our niche market, I fear that the smaller motor offerings will not become available any time soon - which will have a significant impact upon certain areas of the hobby. However, very small and well engineered motors do seem to be already in available in differing voltages. Whilst I am myself pursuing the Protocab route, I do think that the motors I am likely to use need to be suitable for wider applications if for no other reason than the incentive will then be there to ensure finely engineered solutions ... I am not yet (indeed if I will ever be) good enough to prototype my own set ups, and am therefore reliant on collective expertise and output.
Tim Lee

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PeteT
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Re: Thoughts on Motors

Postby PeteT » Wed May 10, 2017 10:09 am

Le Corbusier wrote:
Would it be possible to run different voltage motors on the same DC/DCC system by utilising some electronic wizardry?


Yes, as Tim has already noted for DCC a max voltage can be programmed into the decoder.

For DC systems, as long as the resistance of a motor is known and its maximum voltage, then a resistor can be used to balance. That said, if it is a 6V motor with 0.5A load, then the resistor is going to be drawing the same so needs to be able to both cope with and dissipate 3W of heat (P=IV, or V^2/R).

junctionmad
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Re: Thoughts on Motors

Postby junctionmad » Wed May 10, 2017 12:04 pm

with the Internet and access to Bangood and AIixpress, I see the availability of suitable motors are no issue at all, I have 20 motors in two sizes all for about £1 a motor , nice quiet 12V capable and powerful ( inclusion mitsumi and a bigger can motor )

certainly way better when all we had was a X04 !!!

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Jol Wilkinson
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Re: Thoughts on Motors

Postby Jol Wilkinson » Wed May 10, 2017 12:57 pm

junctionmad wrote:with the Internet and access to Bangood and AIixpress, I see the availability of suitable motors are no issue at all, I have 20 motors in two sizes all for about £1 a motor , nice quiet 12V capable and powerful ( inclusion mitsumi and a bigger can motor )

certainly way better when all we had was a X04 !!!


I've just had a trawl through both those sites (as well as RS Online who have some eye wateringly expensive high end stuff) but other than the small Mitsumi (of which I have a couple to test) didn't spot anything else of interest. Can you share details of the motors you have.

billbedford
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Re: Thoughts on Motors

Postby billbedford » Wed May 10, 2017 1:09 pm

There also the bigger motors sold by Nigel Lawton. The 8x12 is similar to the one used by Dave Jones in his Kernow locos and there is also a 10x12 which is reasonably powerful.
Bill Bedford
Mousa Models
http://www.mousa.biz

junctionmad
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Re: Thoughts on Motors

Postby junctionmad » Wed May 17, 2017 10:32 am

Jol Wilkinson wrote:
junctionmad wrote:with the Internet and access to Bangood and AIixpress, I see the availability of suitable motors are no issue at all, I have 20 motors in two sizes all for about £1 a motor , nice quiet 12V capable and powerful ( inclusion mitsumi and a bigger can motor )

certainly way better when all we had was a X04 !!!


I've just had a trawl through both those sites (as well as RS Online who have some eye wateringly expensive high end stuff) but other than the small Mitsumi (of which I have a couple to test) didn't spot anything else of interest. Can you share details of the motors you have.



The Mitsumi motors are very nice and very small outline , I have one in a 4 wheel diesel shutter chassis and two in a bigger diesel. The main drawback is the 1.5mm shafts

I have a bigger motor with 2mm shafts sourced from AliExpress ( it has a yellow plastic end ) which I find is a quiet and powerful motor , I do however design my gearboxes to remove any trust forces from the motor bearings as these motors don't have particular robust shaft bearings. I'll have a search for the link later

junctionmad
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Re: Thoughts on Motors

Postby junctionmad » Wed May 17, 2017 11:28 am

heres the bigger motor

https://www.aliexpress.com/item/New-Hig ... 0.0.QMAXQ0

Screenshot 2017-05-17 12.27.49.png
Screenshot 2017-05-17 12.27.49.png (176.56 KiB) Viewed 5837 times

David Knight
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Re: Thoughts on Motors

Postby David Knight » Tue Jun 13, 2017 1:44 am

A recent experience has made me wonder about replacement parts, specifically brushes, for existing Mashima motors. One of my engines started to smoke, very realistically, except for the fact it had no smoke unit on board. After taking the body off and running it I discovered that the culprit was me and an overenthusiastic dose of oil on the bearing nearest the commutator :oops: . The motor has been stripped down and degreased with IPA so no damage this time but had the brushes been cooked where would I get replacements? Would a hard, say 6H pencil lead, be any good as a substitute or is the graphite in brushes that much harder?

Cheers,

David

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Horsetan
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Re: Thoughts on Motors

Postby Horsetan » Tue Jun 13, 2017 4:06 pm

nigelcliffe wrote:
Jol Wilkinson wrote:....
So either a different style of motor or a more efficient drive system is required. The N20 gear system referred to doesn't provide the right angle drive we usually require. They are generally quoted as being suitable for applications where a fixed speed is acceptable, so whether the motors will have a performance "range" that suits our needs is unknown. ....


There are two configurations of N20 style motors/gearboxes - one with the shaft inline with the motor, and one where it exits underneath the motor. The 3mm Society Journal article discussed both, in the context of 3mm scale steam locos. The "inline" motor needed a crown/pinion to turn the shaft through 90 degrees and was the only option which fitted a 3mm scale tender steam loco. ....


Nothing wrong with crown-and-pinion or bevel gears. Small ones are available from Ultrascale, Gizmodo, and a couple of other suppliers. Team them with spur gears, RG4 style.
That would be an ecumenical matter.

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RobM
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Re: Thoughts on Motors

Postby RobM » Tue Jun 13, 2017 4:21 pm

David Knight wrote:Would a hard, say 6H pencil lead, be any good as a substitute or is the graphite in brushes that much harder?

Cheers,

David


David, pencil 'lead' is made from graphite and clay, sometimes with wax added......methinks not an alternative for the graphite in bushes as the clay would gum up the commutator.
Rob
http://www.robmilliken.co.uk
Updated December 2016

David Knight
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Re: Thoughts on Motors

Postby David Knight » Tue Jun 13, 2017 8:17 pm

RobM wrote:
David Knight wrote:Would a hard, say 6H pencil lead, be any good as a substitute or is the graphite in brushes that much harder?

Cheers,

David


David, pencil 'lead' is made from graphite and clay, sometimes with wax added......methinks not an alternative for the graphite in bushes as the clay would gum up the commutator.
Rob


Ah, didn't know about the clay part so I see what you mean about the gumming up. Back to the drawing board,then.

Thanks Rob.

Cheers,

David

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Jol Wilkinson
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Re: Thoughts on Motors

Postby Jol Wilkinson » Tue Jun 13, 2017 9:24 pm

Horsetan wrote:
nigelcliffe wrote:
Jol Wilkinson wrote:....
So either a different style of motor or a more efficient drive system is required. The N20 gear system referred to doesn't provide the right angle drive we usually require. They are generally quoted as being suitable for applications where a fixed speed is acceptable, so whether the motors will have a performance "range" that suits our needs is unknown. ....


There are two configurations of N20 style motors/gearboxes - one with the shaft inline with the motor, and one where it exits underneath the motor. The 3mm Society Journal article discussed both, in the context of 3mm scale steam locos. The "inline" motor needed a crown/pinion to turn the shaft through 90 degrees and was the only option which fitted a 3mm scale tender steam loco. ....


Nothing wrong with crown-and-pinion or bevel gears. Small ones are available from Ultrascale, Gizmodo, and a couple of other suppliers. Team them with spur gears, RG4 style.


Ivan,

I've already looked at different gear options, initially as a way around using worms.

The Ultrascale Type 1 contrate gear sets would do that, followed by a spur gear train to get the sort of ratios we normally used. So they would be okay for a "traditional" set up.

The Type 2 can be bought with a 2mm or 1/8" final bore so could be used as the final stage in a gear train. With a 2.9:1 ratio they would need a 10:1 to 20:1 spur gear train - in line with the motor shaft - to get into the right overall ratio area. However, as they are moulded from plastic, with what looks like fairly fine teeth on the final gear, I would be concerned over their reliability, especially with larger motors and heavier locos.

I looked at the Gizmodo sire and couldn't make any sense of it. Perhaps you can provide a link to the relevant section covering gears, or any other site with suitable size/bore gears, preferably in metal if wanted for final drives.

Jol

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Horsetan
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Re: Thoughts on Motors

Postby Horsetan » Wed Jun 14, 2017 12:31 am

Jol Wilkinson wrote:....I looked at the Gizmodo sire and couldn't make any sense of it. Perhaps you can provide a link to the relevant section covering gears, or any other site with suitable size/bore gears, preferably in metal if wanted for final drives....


Gizmodo refer to their bevel gears as "mitre gears" on their website.

I will look for the German / Swiss site which sells miniature bevels.
That would be an ecumenical matter.

billbedford
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Re: Thoughts on Motors

Postby billbedford » Wed Jun 14, 2017 8:06 am

Jol Wilkinson wrote:The Ultrascale Type 1 contrate gear sets would do that, followed by a spur gear train to get the sort of ratios we normally used. So they would be okay for a "traditional" set up.

The Type 2 can be bought with a 2mm or 1/8" final bore so could be used as the final stage in a gear train. With a 2.9:1 ratio they would need a 10:1 to 20:1 spur gear train - in line with the motor shaft - to get into the right overall ratio area. However, as they are moulded from plastic, with what looks like fairly fine teeth on the final gear, I would be concerned over their reliability, especially with larger motors and heavier locos.


If you were worried about the tooth strength of the contrate it could always put as the first stage of the train.

The problem with all spur gear arrangements is the volume they occupy. The gear of the smallest 10:1 pair with a fine 0.3 mod teeth would be in the region of 30mm diameter. The alternative would be two stages of 3.2:1 or three of 2.15:1. Probably OK if you wanted a portiscap type gear box, but too big for anything small.
Bill Bedford
Mousa Models
http://www.mousa.biz

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Jol Wilkinson
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Re: Thoughts on Motors

Postby Jol Wilkinson » Wed Jun 14, 2017 12:08 pm

billbedford wrote:
Jol Wilkinson wrote:The Ultrascale Type 1 contrate gear sets would do that, followed by a spur gear train to get the sort of ratios we normally used. So they would be okay for a "traditional" set up.

The Type 2 can be bought with a 2mm or 1/8" final bore so could be used as the final stage in a gear train. With a 2.9:1 ratio they would need a 10:1 to 20:1 spur gear train - in line with the motor shaft - to get into the right overall ratio area. However, as they are moulded from plastic, with what looks like fairly fine teeth on the final gear, I would be concerned over their reliability, especially with larger motors and heavier locos.


If you were worried about the tooth strength of the contrate it could always put as the first stage of the train.

The problem with all spur gear arrangements is the volume they occupy. The gear of the smallest 10:1 pair with a fine 0.3 mod teeth would be in the region of 30mm diameter. The alternative would be two stages of 3.2:1 or three of 2.15:1. Probably OK if you wanted a portiscap type gear box, but too big for anything small.


Bill,

agree completely. The High Level "gearboxes" use a train of smaller reduction gears to get a compact unit. Branchlines, LRM and other use traditional worm gears to provide simpler gear trains of suitable ratios.

I started looking at contrate gears some time ago to give a "reversible" drive which Portescaps have but can't be achieved with worm gears. I was also interested in right angle gear options after seeing the references to the N20 type of motor/gearbox units. However I couldn't easily find a suitable bevel gear set with correct bore sizes (3.0 or 4.0 mm gearbox output shaft and 1/8" axle. In addition they were all to big to fit into 16mm wide frames (never mind 12mm for OO modellers).

We have become used to having a supply of 12v motors, of suitable sizes for 4mm models and several ranges of gears, etched motormounts, etc. developed to compliment these. There are lots of small motors available cheaply on eBay, but lots are lower voltages than the maximum 12 volts we normally use (and have invested in DC or DCC control sytems to suit). With the exception of the limited range of 12v Matsumi motors already identified, we have yet found replacement for the Mashima range, although at least one importer is looking into it.

We may have to rely on someone investing in commissioning motors to suit our needs. It's become popular with RTR OO locos and stock, so it may be practical. Crowd funding would be another option, but that might be more difficult getting a higher number of people to invest in a much cheaper product than a £100+ loco.

Jol

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Russ Elliott
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Re: Thoughts on Motors

Postby Russ Elliott » Wed Jun 14, 2017 12:19 pm

I've nothing against bevels, but they do require very precise positioning on both axes.

Crepello
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Re: Thoughts on Motors

Postby Crepello » Wed Jun 14, 2017 12:40 pm

Russ Elliott wrote:I've nothing against bevels, but they do require very precise positioning on both axes.

Yes. You can achieve anything from Portescap whirr to Hornby-Dublo Co-Bo whine. In applications where the motor is remote from the driven axle, driving via a shaft to a floating right-angle gearbox, the lack of final stage reduction will also imply a shaft torque of similar magnitude to the driving axle torque.


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