Garden Railway Forum

Pictures of yesterday afternoons trundle.
This train is my most favoured a 3 Truck shay pulling loaded log cars, a work and end caboose.

Rik

My latest addition to the loco roster.
A railmotor bashed together from an LGB coach, a toy train diesel and wagon, an Aristocraft motor block and "Rogers front end" and lots of styrene.
Motor control is a Syren 10A robotics motor controller (https://www.dimensionengineering.com/products/syren10), sound a MyLocoSound card, a 2.4GHz receiver with 10 NiMH cell to give a nominal 12V battery (in grey box).

The wagon is an Aristocraft tender chassis with a wooden body built on it.

All in all this is made out of bits from the parts bin.

Great to see someone doing actual modelling.
Nicely done - it will provide a useful way for those cane mill workers to get to work.

(Thanks for the link to the esc. I will discuss with you somewhere else.)

An attractive little model. The first photo threw me initially, I didn't spot it was two photos and couldn't figure out why the van was 1.5 times bigger and why there was a balcony marshalled between the carriage and the van. Then the mists cleared and it all made sense.

Does the ESC regenerative feature actually work on a small model like this do you think? I do like the idea but I'd have thought it would require something with a bit more momentum - or would it be inertia ( he says, dusting off his rusty. A Level physics knowledge)....

Rik
PS my spell check prefers "degenerative ......."

ge_rik wrote: ↑Mon Aug 02, 2021 7:36 am An attractive little model. The first photo threw me initially, I didn't spot it was two photos and couldn't figure out why the van was 1.5 times bigger and why there was a balcony marshalled between the carriage and the van. Then the mists cleared and it all made sense.

Does the ESC regenerative feature actually work on a small model like this do you think? I do like the idea but I'd have thought it would require something with a bit more momentum - or would it be inertia ( he says, dusting off his rusty. A Level physics knowledge)....

Rik
PS my spell check prefers "degenerative ......."

Rik,
The photo is merge of 3 pictures (to keep the count down)
I have no idea whether the regenerative feature works or not.
I only have one of these ESCs, I originally bought it to power my 3 truck Shay (3 motors) but took it out and replace it with a Pololu Simple motor controller which I am pleased with as they also have a Lipo undervoltage cutoff feature. I was moving toward standarising my ESCs with Pololu but now have 2 Mitroniks Viper loco 10 EScs, so much for standardising.

Greg,
The pololu are readily available from a store in Newcastle NSW "Core electronics".
https://www.pololu.com/category/94/polo ... ontrollers

ge_rik wrote: ↑Mon Aug 02, 2021 7:36 am Does the ESC regenerative feature actually work on a small model like this do you think? I do like the idea but I'd have thought it would require something with a bit more momentum - or would it be inertia ( he says, dusting off his rusty. A Level physics knowledge)....
Rik
PS my spell check prefers "degenerative ......."

I love degenerative braking!
Not to hijack the thread with maths, but I did a few calculations on the energy that might be recovered.

The losses in the train friction (bearing and wheel-to-rail) and loco electrical losses and gear friction FAR outweigh the energy that could be recovered by regenerative braking.
I estimate a ‘large’ train of 20kg running on level track, at 1m/s which is 70 scale kph, uses around 350-700 Joules for every minute it runs.
The train making a stop theoretically generates only 10 joules of kinetic energy – less because of motor losses. Absolutely negligible.
The same train descending 1m in height, has a potential energy gain of 200 joules, but the losses in friction above, help to slow the train, so maybe only 50 joules could be recovered.

Just to get a perspective, the energy stored in a typical train battery that I use of 12V, 2000mAh is 24watt-hours which is 86400 Joules, so the figure of 350joule/minute I used above would give 4 hours of running.

GAP wrote: ↑Mon Aug 02, 2021 10:59 pm
The photo is merge of 3 pictures (to keep the count down)

Graeme,
I guess you must have missed the announcement on 27th July? The picture limit has been raised to 6 per post.

https://gardenrails.org/viewtopic.php?f=2&t=13595

gregh wrote: ↑Tue Aug 03, 2021 4:36 am The losses in the train friction (bearing and wheel-to-rail) and loco electrical losses and gear friction FAR outweigh the energy that could be recovered by regenerative braking.
I estimate a ‘large’ train of 20kg running on level track, at 1m/s which is 70 scale kph, uses around 350-700 Joules for every minute it runs.
The train making a stop theoretically generates only 10 joules of kinetic energy – less because of motor losses. Absolutely negligible.
The same train descending 1m in height, has a potential energy gain of 200 joules, but the losses in friction above, help to slow the train, so maybe only 50 joules could be recovered.

Just to get a perspective, the energy stored in a typical train battery that I use of 12V, 2000mAh is 24watt-hours which is 86400 Joules, so the figure of 350joule/minute I used above would give 4 hours of running.

Thanks for the analysis, Greg. I did wonder if it would be theoretically possible in our scale. Actually, thinking about it, mostly our mechanisms use worms so, presumably, regenerative braking wouldn't actually work anyway. Wouldn't it require spur gear transmission or chain drive to work?

Rik

philipy wrote: ↑Tue Aug 03, 2021 5:38 am

GAP wrote: ↑Mon Aug 02, 2021 10:59 pm
The photo is merge of 3 pictures (to keep the count down)

Graeme,
I guess you must have missed the announcement on 27th July? The picture limit has been raised to 6 per post.

https://gardenrails.org/viewtopic.php?f=2&t=13595

I did see the announcement but merged them for another forum that has a limit and just used the same source.

ge_rik wrote: ↑Tue Aug 03, 2021 8:17 am

gregh wrote: ↑Tue Aug 03, 2021 4:36 am The losses in the train friction (bearing and wheel-to-rail) and loco electrical losses and gear friction FAR outweigh the energy that could be recovered by regenerative braking.
I estimate a ‘large’ train of 20kg running on level track, at 1m/s which is 70 scale kph, uses around 350-700 Joules for every minute it runs.
The train making a stop theoretically generates only 10 joules of kinetic energy – less because of motor losses. Absolutely negligible.
The same train descending 1m in height, has a potential energy gain of 200 joules, but the losses in friction above, help to slow the train, so maybe only 50 joules could be recovered.

Just to get a perspective, the energy stored in a typical train battery that I use of 12V, 2000mAh is 24watt-hours which is 86400 Joules, so the figure of 350joule/minute I used above would give 4 hours of running.

Thanks for the analysis, Greg. I did wonder if it would be theoretically possible in our scale. Actually, thinking about it, mostly our mechanisms use worms so, presumably, regenerative braking wouldn't actually work anyway. Wouldn't it require spur gear transmission or chain drive to work?

Rik

The ESC is designed for "Battle bots" that are big heavy items and have motors driving the wheels directly, I didn't buy it for the regen function but the 10A current capability and the stick centre calibration at switch on function.