NYC "S" Motor a Gauge 3 Locomotive

[scottychaos]

Ralph,

thats not my photo..it was sent to me by the photographer to use on my "NY Alcos" webpage..let me dig through my email for the photographer's name, and I should be able to put you in touch with him directly..

Scot

[cabbage]

The carbon greasers have been added to the top and the electrically conductive epoxy is holding them well. The "drop test" shows that they can conduct 6 Amperes so the pair of them should have no problem feeding power to the motors. The greasers are simply 2 old blocks of graphite armature connectors that I grooved with a set of clay scrapers.



The next shot shows the underside of the cab roof where I have strted assembling the power control system. The relay on the left is the Fwd/Rev and the one on the right is the main power feed. Both of them are rated at 20 Amperes at 12Volts. The hardwiring from the coils connects to the slide switches on the roof. The main PCB will sit to the right of the relays. Holes will be bored through the roof to connect to the resistors on it. The roof electronics connect to the lower power supplies by male Lucar "spades", this means that when the roof is taken off -there is no chance of a short from the power bus bars below.



The system will be a hybrid with 12volt electronics and 6 volt motors, (both sets of motors will be coupled in series). As normal I will leave the front and rear windows unglazed -this provides a cooling draught of air as the loco moves!

regards

ralph

[cabbage]

Well I initially imaged that there would be quite a lot of egg on my face -but the fact is tht this does seem to be comming together far easier than I thought possible. It is now nearly 10pm and this evening everything hs gone very well!!!

I started out with my collection of brass strips.



And after some sawing with my hacksaw I ended up with the main beam cut from 1 inch strip and the horn guides from ½ inch strip, all together in the jig.



Each of the horn guides was drilled with 3mm holes at 7mm and 18mm intervals



The completed drilled horn guides are then returned to the jig and the main beam bored from them.



The whole thing is assembled with 3mm nuts and bolts and it is now ready for soldering.



Note; brass nuts and bolts are used so that when the assembly is heated prior to silver soldering, the assembly expands and contracts at the same rate -this will reduce twisting and warping.

regards

ralph

[Anonymous]

Ralphy-poo,

You going to cut those bolts off, abit long? Or are they to be that long??

Toadie

[cabbage]

William,

You seem to have got slightly confused due the zoom ratio and perspective of the shot. The whole assembly is only 24cm long and the sheet is 65 thous thick. They are 9mm setscrews, and there is about 3 nuts worth of thread projecting through the beam. But, at the end of the process I will trim the excess threads with a piecing saw.

This evening I am hoping to start work on the 4 end pieces -which is frankly just nasty...

regards

ralph

[cabbage]

It is just after 7:30pm and the evening was a nasty as expected!!! Silver soldering is not hard, I would say actually it is very easy -even when compared to electrical soldering. The main problem is that everything operates at dull red heat...

Having sawn all the sections to size and tacked them together with CA I loaded them onto the "forge".

I then opened all the doors and windows!!!

The safety sheet for MAPP (Metyl Acetyl Propadine) says that is is safe to use indoors -however the smell may be objectionable. The smell is not unlike sweaty socks and ripe drain...

Anyway with my green safety glasses and my red gloves I lit my bottle torch and began. I torched up all four of the end pieces and duly threw them into the bucket of water at the end of the process -this cracks off most of the flux and saves on cleaning time. The flux I use is one I learned with at school, equal parts Borax and Olive oil, sticky, smokey -but it cuts through any oxide layer!!!

I then torched the horn guides to the main beam, and dunked them.

The end pieces are joined by the one top joint, this makes handling them until the bottom bar is in place -slightly fraught!

At the end of 2 hours work I have transformed the beautiful brass in the pictures above into the blackened, sooty and flux stained assembly below:



regards

ralph

[cabbage]

Ok -this is the end of my "free time" as I will be very busy for the forseeable future... The chassis rails have been soldered together and the assembly epoxied to the base of the 'S' motor. You can see the horn blocks in the horn guides.

It is likely to be another month or so before I can return to this -so this is the last shot!



regards

ralph

[cabbage]

Well... After the week from Hell I did get some time on Saturday Afternoon to sit and semi relax!!!

The shot below shows the grease boxes (U shaped channels of Aluminium) have been bonded to the horn guides. They will be bolted with 2mm nuts and bolts to the hornguides hopefully by the end of this week. The bottom bar of the chassis frame has been fitted and it holds the horn guides against the pressure of the springs. These sit in a typical home made assembly of: 6mm washer, spring, 6mm washer, length of brass tube, 6mm washer. The central shaft is 4mm brass tube tapped to 2.5mm and the this is then bolted through the grease box. The shaft is "damped" by having the brass tube above (which it slides up and down in) packed with greased felt. The net result is not unlike an inverted "McPherson Strut".



I had some fun and games with Hookes Law working out the suspension springs... The bogie has to have more pressure at the rear, the combined forces of the front bogie plus the external power axle must equal the force on the internal power axle!!! (There are times when I wish I was 15 again -I remember it as all being so easy)...

The two motors have been fitted to the cab these have been installed transversely and will drive the power axles via cogged belts after having been stepped down 8:1 with gearing. A version of the "Silent Block" soft start system to ease the strain on the take from the motor will also have to be fitted. But as I have done this before on my EF-1 it is not going to be that hard -except for the space limitations!!!

regards

ralph

[cabbage]

Today is Friday the 13th.... This simple fact explains why so much has gone wrong today!!!! I blew up a motor -this has never happened before and these particular motors I am very well versed with. I also seem to have lost my temperature controlled soldering iron -not much you may think -but it is about 30cm square...

Anyway -back to the Build Log.



As I am now down to one motor I have had to re-jig the drive system. The motor drives a 15 tooth spur to a 60 tooth spur, on the same shaft is an 8 tooth sprocket. This then drives, via a ladder chain, a 16 tooth sprocket. The final drive to the wheels is taken from this shaft. The net reduction is 1:8 which is, I think, still a bit high and I am contemplating dropping it down to a ratio of 1:16 by interspacing a second 8 tooth sprocket on the output shaft and then taking this down to the drive axle system.

According to Henry Greenly a ratio of 1:6 is quite adequate for a 2 1/2 inch gauge loco, but I do rather like my locos to run slowly and smoothly... After having played around a bit with 16mm models I am actually quite amazed at how different the Gauge 3 models are. The scale is smaller but the gauge is larger. The sheer MASS of a Gauge 3 model is at least 10 times that of the typical 16mm model that I have built. Even without its SLA power bricks the model weighs in at 2Kg easily.

regards

ralph

[altterrain]

Did it smoke and burst into flames?

-Brian 

[cabbage]

No,

Nothing quite as spectacular as that. One of the commutators has come detached from the rotor -thus 2 of the 5 poles are U/S. It wobbles well -but of course will no longer rotate... I have also been doing some quick work with the HP51. I WILL need to step down the final drive to 1:16. The torque curve from the single motor is wrong for starting from a standstill. If I simply increase the voltage the 'S' motor will take off like a scalded cat -rather than smoothly accelerating to its final velocity.

I did however find my soldering iron -it was in the oven...

regards

ralph

[Anonymous]

Dude, your blown.........but I like it!

Toad

[cabbage]

Well as I sit here at the end of the wreckage of a day....

I suppose I had better tell you what I did over the weekend then... The shot below shows that some of the power and lighting wiring has been installed. The power is taken from two 6 volts SLA batteries arranged as +6 and -6 volt line feeds, (there is a reason for this!)



Above the piece of tag board there is the main power fuse (6 Amps) in the line between the two batteries on what is (nominally) the Zero Volt line. I have used the std EU colour coding for the wiring -which may look a little strange to US eyes...

Red and Black are negative and positive DC.
Blue and Yellow are DC lines of variable polarity -but always of opposite polarity.
Green and Orange are '0' and '1' TTL voltages.

The relays all use 12 Volts.
The Motor uses 0-6 Volts fed from a serial controller.
The serial controller is fed from a 12 Volt line.
The lighting LEDS are 5V and hence all use TTL.

When the loco reverses the relay flips the DPDT relay on the supply line to the lighting circuit and all the lighting LEDs that have been forward biased turn off and those that are reverse biased -turn on(!)

regards

ralph

[altterrain]

When the loco reverses the relay flips the DPDT relay on the supply line to the lighting circuit and all the lighting LEDs that have been forward biased turn off and those that are reverse biased -turn on(!)

Hi Ralph,

Not to be a smart alec but why did you need a relay to reverse your LED lighting? When I wired up my boxcab last year, I ran my LEDs on a single circuit and merely reversed the input for the reverse lights since the LEDs will only light up in the proper power orientation. It works just great for battery or track power though I notice on track power the "off" light may flicker a bit from the PWM.

-Brian 

[cabbage]

No -it is not a "Smart Alec" question!

The reason I am using a relay is the fact that the LEDs are all running from a 5Volt TTL line and if I simply connected them to the 12Volt line the voltage would swamp the diode effect, and they would conduct, (for a "short" while....) The ditch lights/stop light LEDs are a dual red/yellow LED with three legs and a common anode.

I also prefer to isolate and test individual circuits -which I can do very easily with a relay. You can feel a relay "clunk" something you cannot do with bistable flip flop chip!

regards

ralph

[cabbage]

The morning post has delivered all the wheels required for the 'S' Motor. So on the kitchen work top there are eight 42mm wheels and eight 32mm wheels (2-D0-2). All have been supplied as seperate wheels and axles, (as requested).

The next job is the drill the axles on the 42mm wheels to take the 3mm bolt that will act as the "pin" to the pairs of 16 tooth sprockets that will be assembled around it. The 32mm wheels will be the wheels for the front and rear bogies. These will be of the "compensated" type with the compensation springing being a torsion bar and there will be no vertical springing. This will force all the weight of the loco onto the eight driving wheels.

This is the time that I really have to decide wether I want to fit an English type "instanter" coupling or a US style "knuckle". There are pluses and minuses to both answers... If I fit an "instanter" then it is in keeping with the period and premise of a Colonial Railway and all my wagons and carriages will couple to it! If I fit a "knuckle" then I would have to build a converter wagon -but I would know that it was correct!!!

regards

ralph

[John Busby]

Hi cabbage

That's a tough choice make it real or make it so it can haul your exixting stock.

If it was me I would put the couplings the rest of my stock use so it can go into service after the shake down trial's it's that, or use a paper clip coupling untill you build a converter wagon. 

They have the problem that 1/2 the time they are unsuitable for the train to be hauled and if painted a high vis colour so you can find it quick stand out like the preverbial sore thumb.

regards John Busby

[altterrain]

Maybe a compromise - a knuckle coupler on the front end for show and a instant coupler on the back side for pulling your cars.

 -Brian

[cabbage]

At the end of a feverish bout of activity on a wet and windy Sunday Afternoon -don't you just love the "English Summer".... The 'S' Motor now sports four completed drive axles and sproket assemblies. The axles were drilled by the usual trick of placing a scrap of plywood on top and drilling through that -to prevent the drill from "wandering" as it bit into the curved top of the axle.

The sprockets were step drilled up the required bore of 6mm and then fastened around the 3mm bolt with cross 3mm bolts. This gives a "cage" assembly that will rock slightly. The "take up" of the cage is damped by it having rubber grommets bear on the pin -sort of a "silent block" set up!!!

The following shot shows the 'S' Motor sat for the first time on its wheels -the chassis is not loaded with the batteries so sits slightly "up" from where it will normally stand.



Here is a, (slightly burry -sorry!), shot of the underside -showing the dual chain sprockets and the axles.



Fitting the wheels to their axles is now routine. As they are a "taper fit" you are supposed to either have to compress the wheels onto the axles with a press or a big bench vice. My method uses two reels of solder and a 5Kg sledge hammer, dropping the head onto the top reel from 1 metre height ensures a perfect fit first time!!!

regards

ralph

[Anonymous]

You know Ralph would like to buy one of those things from yeah, not that one but maybe a different model but I be shocked to see the price tag!

And my motor could never burn up either

Toad

[cabbage]

William,

According to the spreadsheet -the cost so far is about £140 -I believe it should cost no more than a further £50 to complete. Most of what is required I would call the "frilly stuff", as the bulk of the model is complete. I think I have done well to keep within my budget of £10 per week.

A typical Gauge 3 coach will cost you around £275 in pre built condition, a small RTR Gauge 3 loco will easily cost you around the £1,000 mark.

regards

ralph

[cabbage]

This is sort of the "momentous" event...

The last drive chain has been wrappd around its sprocket and the motor "blipped" with a battery and it all moves -but it will need some oiling!!!



The chain is of the "self guarding" type and had a U shaped cross section. You have to bend back the wires to seperate the chain and then rebend the wires to rejoin them. This is not normally done without "words" and the "blood sacrifice' as the ends of the chain are needle sharp...

Now that the loco sits on its rails I can measure up for the front and rear bogies. As I have said before these will be of the simple compensated type and will use torsion bars. The initial drawing is shown below.



The ends of the torsion bars will be held in "choc block" connectors, normally used for connecting cables -but the brass unions will be silver soldered to the sides of the bogies. The central "saddle" fitting is just a tube with a flat plate and the sides of the bogie pivot on M4 setscrews locked into the tube. The saddle sits "off centre" to make the springing of the leading/trailing axles lighter than that of the inner most axles.

regards

ralph

[Anonymous]

Have to say that is a smart chain to use there!

"The chain is of the "self guarding" type and had a U shaped cross section."

Toad

[cabbage]

The upload server at Virgin seems to have blown a fuse -so I am sorry all you have is a verbal report...

I have constructed the two bogies -as seen above -they are simply (at the moment) raw plates of brass with suitable holes in them -they have been bolted to the from Adams union and after a due amout of "twiddling" the spacing is as near as pefect as I can get it!

The LEDs have been wired up to the roof relays, the feed from the main power switch energises the fwd/rev and LEDs relay as well as the ESC. Thus there are no live circuits when the power switch is "off". I will admit though that I have blown more than a few fuses this morning...

To counteract this I have built some balsa wood "shielding" to prevent the "whirly bits" comming into contact with the "sparky bits" -to quote my son!

The model is now ready for its paintwork, which will be "Fall Grey" and Black. The choice of the colour is not accidental, as this was the grey used for locomotive "portrait" photographs for early B&W photography. It is actually a slight pinky violet or lilac colour to balance the "blue" of normal sunlight.

regards

ralph

[cabbage]

I would imagine that "SU" or "ROOT" have used kill -9 PID on the FTP server, because whatever the problem was -it has been removed! So, here at last are the pictures of what I have been doing over the weekend.



This is the side shot of the front bogie, you can see that the saddle has been bolted to the frame and the transverse springs provide the down force to keep the wheels in contact with the rails.



This shot is looking straight down the centre of the bogie. You can see the "nosing" springs that control the rate of shift of the bogie and the lateral pivot bar.



And finally a side shot showing the front and rear bogies and how the loco now sits as a 2-D0-2.

regards

ralph

[Anonymous]

Looks like a freakn tank now Ralph! You kill the motor again????

Toad

[cabbage]

William,

The motor is fine, and I have returned the defective one for a refund. My son has reminded me that I have not posted the pictures of the lights in action.



This shows the white LED in its position in the top headlamp and the yellow LEDs lit i.e. the locomotive is heading towards you...



The direction is now reversed and the yellow LEDS now shine red. The other white LED can be seen reflecting off the splash tiles.

If you look at the drawing from the Henry Greenly book then the model and the drawing match. The bogies will move outwards once the batteries are loaded (i.e. it is then 2.5Kg heavier)



regards

ralph

[Benjamin Maggi]

It's really coming along now. I wonder how much it will pull... I would bet it could pull a lot!