Thoughts on Motors

Model and prototype rolling stock, locos, multiple units etc.
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Le Corbusier
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Thoughts on Motors

Postby Le Corbusier » Sun May 07, 2017 12:15 pm

I can't find any current live topic which appears to be discussing the demise of Mashima and possible alternative options. I assume that this is a subject that more experienced modellers have been grappling with for some time?

I wondered what if any thoughts people might have had? Do we know if any moves are afoot to convert current gearbox offerings to different spec motors ....

Tim
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Tim V
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Re: Thoughts on Motors

Postby Tim V » Sun May 07, 2017 1:45 pm

The hobby survived the demise of Portescaps, so who knows what is round the corner?
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Penrhos1920
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Re: Thoughts on Motors

Postby Penrhos1920 » Sun May 07, 2017 8:44 pm

Dragon Models have announced a range of Mashima replacements.
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dal-t
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Re: Thoughts on Motors

Postby dal-t » Mon May 08, 2017 6:33 am

John Isherwood of Cambridge Custom Transfers is also selling an alternative - I have a batch, but haven't fitted them to anything yet, so can only say that unloaded they run up and down the rev range very sweetly. To see one fitted in a chassis (if you don't mind visiting 'the other place') go here, or you can visit the manufacturer's site Mitsumi.
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Re: Thoughts on Motors

Postby billbedford » Mon May 08, 2017 6:43 am

Le Corbusier wrote:I can't find any current live topic which appears to be discussing the demise of Mashima and possible alternative options.


Yep. Gives us a chance to see if we still need to use 12v -- Fitting a 14xx 0-4-2T
Bill Bedford
Mousa Models
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jon price
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Re: Thoughts on Motors

Postby jon price » Mon May 08, 2017 10:52 am

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/

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Le Corbusier
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Re: Thoughts on Motors

Postby Le Corbusier » Mon May 08, 2017 11:09 am

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/


Aren't they pretty much the same tech as mobile phones?
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Re: Thoughts on Motors

Postby nigelcliffe » Mon May 08, 2017 11:15 am

Le Corbusier wrote:
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.


Aren't they pretty much the same tech as mobile phones?


Yes and no. Yes the cells inside are similar/same tech. No in the sense that the mobile phone has electronics wrapped around it to monitor the battery and its charging (several famous battery fire devices not withstanding). That's the fundamental issue around LiPo's in model applications - having an adequate electronics surrounding the cell to monitor what charge has been drawn and what charging is being applied.

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Le Corbusier
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Re: Thoughts on Motors

Postby Le Corbusier » Mon May 08, 2017 11:22 am

Yes and no. Yes the cells inside are similar/same tech. No in the sense that the mobile phone has electronics wrapped around it to monitor the battery and its charging (several famous battery fire devices not withstanding). That's the fundamental issue around LiPo's in model applications - having an adequate electronics surrounding the cell to monitor what charge has been drawn and what charging is being applied.


I am pretty certain that the protocab system has the electronics attached to the batteries and they supply their own specific charger. Perhaps Tony could comment?

On the topic of non 12v motors, what would be the pros and cons?
Last edited by Le Corbusier on Tue May 09, 2017 7:08 pm, edited 2 times in total.
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Re: Thoughts on Motors

Postby NorthHighlander » Mon May 08, 2017 12:13 pm

Responding to Jon's thread, at Acc+Ess we fully understand his concerns. He is right that lithium ion can present a safety issue if handled incorrectly, but these issues have been known since the 1970s when lithium batteries first appeared. This link gives a very good summary IMHO of the issues and remedies.
I would, in particular, refer to the section headed 'Safety level of lithium-ion systems'. The three safety layers are very important and I wouldn't think of using batteries without ALL of them in place.
The point he makes about custom rigs is very important. Pressure on any part of the battery, such as a protruding screw head, is not to be recommended but there are two remedies to this: firstly wrap the battery in a strong metal coating and secondly ensure that the protection circuit can rapidly and effectively detect a cell short circuit.
Nigel goes on to make a very important point. Even in the rare cases when a LiPo battery has caught fire, this has often been down to a poor charging regime that has enabled overcharging to take place. The other major cause is not having measures in place to prevent a short circuit causing the cells to overheat and create the thermal runaway described in the Battery University document. (Incidentally, creating a short circuit in any electrical system can cause a fire).
These concerns are the very reason that we have developed the Protocab system as a whole and unified system to include the charger, the specification and production of the battery and the safety devices built into the LCU to which they are both attached to minimise the risk so far as is possible. Beyond that, we hope that modellers will follow the comprehensive safety guidelines and installation guidelines we issue with each product. We take our customers' safety very seriously and the testing regime on all our products, whilst expensive, is essential to enable us to apply the CE mark.

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Re: Thoughts on Motors

Postby NorthHighlander » Mon May 08, 2017 12:15 pm

..I'm sorry, I did not include the link to the Battery University which is:
http://batteryuniversity.com/learn/arch ... y_concerns

Regards

Tony Hagon

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jon price
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Re: Thoughts on Motors

Postby jon price » Mon May 08, 2017 3:24 pm

NorthHighlander wrote:These concerns are the very reason that we have developed the Protocab system as a whole and unified system to include the charger, the specification and production of the battery and the safety devices built into the LCU to which they are both attached to minimise the risk so far as is possible. Beyond that, we hope that modellers will follow the comprehensive safety guidelines and installation guidelines we issue with each product. We take our customers' safety very seriously


I agree entirely, and have no concerns with Acc+Ess products. The problem arises with the smaller and more specialist builds, in particular pre-grouping and industrial prototypes. I have two projects on the go. One will use an 0-6-0DE similar to the 08, a Jinty, and a Dean Goods. It is likely that these are all feasible with tested commercial products like yours. The other has a series of tank engines that will just about have room for the smallest Mashima motors and enough weighting to make them run smoothly. Maybe we will get there, but the temptation to make custom rigs for these would, I feel, lead to problems, whilst the likelihood of manufactured solutions appearing would seem to be far in the future, unless RC is taken up seriously by manufacturers of 2mm scale stuff.

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Re: Thoughts on Motors

Postby NorthHighlander » Mon May 08, 2017 10:13 pm

Thank you, Jon, for your further note clarifying usefully your concerns. 2mm scale is what we call in technical terms 'a challenge'! But we intend to satisfy the many 2mm modellers who are Club Protocab members. The issue is that the manufacturers and individual modellers are somewhat hamstrung by the choice of motors, the theme of this whole thread. As Bill Bedford has intimated, one advantage of freedom from track wiring is that you are no longer limited to 12V motors.
We try to steer modellers towards thinking not about voltage and current but to think in terms of the product of the two, namely power. Batteries, unlike mains based electricity supply, have a finite usable time before they need to be recharged. Whilst lithium based batteries have significantly increased density and thus output from a given volume, they are really only at the leading edge of the possible in terms of usability for model railways.
It behoves us as modellers, then, to start finding ways of conserving this finite resource to maximise power output on the basis of the longest possible running time from the smallest possible battery. For part, we have developed but not yet demonstrated a 5V variant of the Locomotive Control Unit, and we are sourcing suitable 5V motors. This will reduce the footprint of the LCU because the voltage boost from the nominal 3.7V of the battery to 5V requires less size-hungry and relatively inefficient components to boost the voltage to near 12V. A 3V motor actually reduces the voltage, but at this full scale voltage, some laws of physical properties come into force and motor efficiency reduces.
It stands to reason that an equivalent trailing load of wagons on a 2mm train ought to require less motive power (tractive effort) than a 4mm or 7mm train, frictional forces due to rolling resistance also being proportional. However, it is our experience that the power that can be generated even by 2mm motors is far higher than required to move the load for which the loco has been designed. This is why I see so many RTR layouts on Facebook etc. where the trains are moving at vast speeds and accelerating at almost supersonic rates! Loco engineers will design for just enough power for the job and a bit because any excess power is wasted fuel.
We have done loco conversions for customers where we have had to replace the RTR motor with a smaller one, and our customers have expressed surprise that whilst the acceleration is slower and the top speed is lower (i.e. more realistic) the loco is still able to haul the heaviest planned load.
So, our plea is to think power to arrive at the requirement for the smallest motor and smallest battery which will do the job - we are pleased to help!

Best regards

Tony Hagon
Acc+Ess Ltd

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Re: Thoughts on Motors

Postby NorthHighlander » Mon May 08, 2017 10:18 pm

I should add to that last sentence the paradox that we usually recommend that you choose the largest battery that you can find space for. We should also add that high quality motors with as many segments as possible, a high quality gearbox, properly lubricated and well meshing with minimum friction and an effectively sprung chassis on all the rolling stock helps to minimise power demand and therefore battery usage.

TH

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Re: Thoughts on Motors

Postby nigelcliffe » Mon May 08, 2017 10:30 pm

A further comment on Tony Hagon's points about efficiency, and that's losses in gearboxes. I was prompted by an article in the 3mm Society Magazine to look at the small industry standard gearbox/motor combinations which go under the "N20" label. These have spur gears throughout, and appear to have low losses compared to worm drives. I've not looked at measuring actual current consumption (which would give us the real answer), but the 3mm article talked of building locos which can't be stalled compared with the relative ease of stalling a loco with traditional worm drives.

- Nigel

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Jol Wilkinson
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Re: Thoughts on Motors

Postby Jol Wilkinson » Tue May 09, 2017 8:58 am

Perhaps we should be discussing "powertrains" rather than just motors.

As a hobby we are largely reliant on sourcing motors that are already available. We are also faced with the issue that the commonly available motors are cylindrical or "flat cans". To accommodate these they need to be mounted longitudinally in models thus requiring some sort of right angle drive. Traditionally this has involved a worm and gear.

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. The output shaft is usually 3.0mm, so

Few, if any, of our "small suppliers" probably have the resource to individually commission gears produce a dedicated drive system. Ultrascale manufacture injection moulded Nylatron GS contrate and pinion gear sets that could be used as part of a drive train, but nobody has, to my knowledge used them in a commercially available system.

Although some alternatives to Mashima motors have been identified, none provide the same range of size and power characteristics that we had come to appreciate. They also utilise different mounting screw hole locations, thus making several suppliers motor mounts redundant. Much more expensive motors than we have been used to are also available (Falhauber, Maxxon and others) but these probably aren't acceptable to most modellers on cost grounds.

I suggest we need to identify a motor (or range of motors) that will meet the need of the majority of modellers in 4mm (from a suppliers point of view OO, EM and P4 all have to be catered for). The motor mount/gearbox suppliers can then get on with redesigning their products (using exiting or new gear trains) to match them. So far Mitsumi appear to be the most readily available at low cost (usually via eBay). The motors on the Dragon Models site are mainly suitable for 7mm. The smallest is the 1525 (width X length) and the notes state "This motor is ideal for smaller 7mm/ft. scale and some larger 4mm/ft."

We also have to remember that, despite the attractions of wonderful new technology, many people are committed to DC and DCC so their needs shouldn't be written off by the technocrats.

So, some more research by all of us and a bit of head scratching from the suppliers required. I think I know what might be achieved with available items for the gear train to provide a more free running, lower friction product, within the size constrains we have. We still need to identify suitable motors - size, performance and cost - or someone needs to commission something suitable from Mitsumi or the likes. Perhaps the Society - together with the EMGS - might like to research and promote this.

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Re: Thoughts on Motors

Postby billbedford » Tue May 09, 2017 9:46 am

If you look through motor manufacturer's catalogue you will find a wide range of small motors with 3.7 or 5 volt nominal voltages. There are relatively few usable motors made for 12volts. Mashima was probably the last independent manufacturer to dedicate their output to 12v. I suspect that over the next few years we are going to see a move away from the traditional 12v control trough the rails system and toward the sorts of systems used other applications, e.g. computers, small drones etc.
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Le Corbusier
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Re: Thoughts on Motors

Postby Le Corbusier » Tue May 09, 2017 10:04 am

It seems to me that a dual approach is possibly the way forward.

On the one hand a relatively urgent way forward is required to maintain the status quo (particularly for those without pre bought motors.

However, collectively it seems to me that time should also be invested in where things are moving to ... otherwise one risks being marginalised as to influence. The current situation ought perhaps to be seen as an opportunity as well as a bit of a pain ... just a thought?
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Re: Thoughts on Motors

Postby NorthHighlander » Tue May 09, 2017 10:14 am

Nigel makes a very important point about the efficiency of gearboxes. I can't claim any expertise on them, but I think it's notable that the Portescap motor/gearbox combos use(d) spur gears rather than worms. I think the main problem with worms is that there has to be some play to accomodate the forward or reverse thrust, which I guess is less precise in cheaper worm/gear combinations. The point Nigel makes about stalling of the motor with a worm drive is very real and the main reason we quote current handling capability as the stall current of the motor.
I did some research for the efficiency of the complete power train from battery to wheel (because we try to maximise efficiency to maximise effective power from the battery). In this I summarised:
Power losses in the Locomotive Control Unit: 10-30% (the circuit uses electricity)
Motor efficiency losses: 30-50% (depending on the quality of the motor)
Transmission losses: 20-25% (due to frictional forces/meshing)
Multiplying these together result in an overall efficiency of 10%, meaning that only one tenth of the available power from the battery is arriving at the wheels. We notice this dramatically when comparing a loco fitted with a high quality motor, gearbox and free running chassis (preferably sprung, but, at least, compensated) with an RTR loco of moderate vintage. The reason we applied a 'dead zone' to the controller (approx 5 degrees either side of 'off') was to accommodate the former type of loco, usually fitted with a Portescap, which, when the control was set to zero and because of slop in the potentiometer, was causing the loco to move very slowly in the opposite direction. Contrast that with some RTR locos which require the controller to be set well past 90 degrees before having sufficent voltage applied to overcome the various inherent losses. It is to accommodate this wide range of efficiencies that we are introducing 'Glide Control' to use feedback from the motor to compensate for the 'stiction' that is the bane of realistic loco starting and stopping (and which, of course, has been applied to DCC decoders for the same reason).

Best regards

Tony Hagon

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jon price
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Re: Thoughts on Motors

Postby jon price » Tue May 09, 2017 10:58 am

The 6v motors on Nigel Lawton's site seem interesting, and there is a CLAG example of using them in DMUs. The issue is perhaps their relative lack of power and/or the efficiency of the friction drive train. Nevertheless for the small prototypes we wouldn't be expecting huge trainloads or high speeds. a smaller loco control board would be needed as Tony Hagon explains, plus a smaller battery pack to fit in. At this size I am guessing that the battery pack will actually provide the weight for track holding.
http://www.nigellawton009.com/6V6mmx10m ... otors.html
http://www.clag.org.uk/axle-hung.html

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Re: Thoughts on Motors

Postby Philip Hall » Tue May 09, 2017 1:00 pm

Maybe we should look at where the motors that the big RTR manufacturers use come from? Maybe they are made 'in house'? I cannot believe that RTR is ever going to move away from traditional 12v motors. That is the largest market for them, and whatever we think, that will always be so. Some of the motors fitted to the latest Hornby and Bachmann engines have been very good, so if we could source them it might be useful.

I don't think we should be looking away from 12v when the RTR boys are still using it. However attractive it might seem to go down a new route of lower voltage motors, if we did so it would cut off a RTR source of supply for many of us. Yes I'm biased, of course, because I model the Southern!

Philip
Last edited by Philip Hall on Fri Jul 07, 2017 4:21 pm, edited 1 time in total.

nigelcliffe
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Re: Thoughts on Motors

Postby nigelcliffe » Tue May 09, 2017 2:18 pm

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. The "underneath" motor could be mounted transversely in a 3mm scale tank loco, or a bogie diesel, with drive from either spur gears or a delrin chain. I'm tempted to look at the transverse option for a small tank engine (eg. J69 or similar) in 4mm scale. It won't quite fit between the back-to-back, so has to sit above the flanges.

The other advantage of the N20's is their very low cost - can be had for under £5 each for complete motor/gearbox. Most can be dismantled for interchanging parts, so if the "underneath" is only available in 5v, just substitute the 12v motor from a different configuration.

- Nigel

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Tim V
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Re: Thoughts on Motors

Postby Tim V » Tue May 09, 2017 2:53 pm

Of course, using DCC, CV5 can be set to cope with motors other than 12V.....
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Re: Thoughts on Motors

Postby grovenor-2685 » Tue May 09, 2017 6:23 pm

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.

Nigel,
is this what you mean by the underneath config? Unfortunately the drawing with that seems to be the wrong one so maybe a bit more searching needed, but the motors with the straight ones are 15mm long so its probably in the region of 25mm allowing for the wiring terminals and the gearbox.
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nigelcliffe
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Re: Thoughts on Motors

Postby nigelcliffe » Tue May 09, 2017 6:43 pm

grovenor-2685 wrote:
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.

Nigel,
is this what you mean by the underneath config? Unfortunately the draawing with that seems to be the wrong one so maybe a bit more searching needed, but the motors with the straight ones are 15mm long so its probably in the region of 25mm allowing for the wiring terminals and the gearbox.
Regards


Yes, in general terms. The size is nearer 20mm than 25mm.

- Nigel


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