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Denney

Denney's New Track

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OK, a couple more questions... The D3800 isn't in stock at any DSE near me (I wish Chermside hadn't moved into the shopping centre, they have NOTHING now).

 

The 13.8v / 0 - 12a is from Jaycar: http://www.jaycar.com.au/productView.asp?I...mp;SUBCATID=381

 

I'm not sure if it's switch mode or not. Why is switch mode no good for slot cars?

 

@gzminiz: Do you have a schematic for the variable regulator? It's something that would interest me because then I can turn down the voltage for just one lane if that person is new to racing while still have the other lane at full speed.

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The regulator will need to be pretty big! I have seen 317K's give up the ghost,so will need at least two transistors off the regulator. All the tracks down here have 15 3055's for regulation! Plenty of grunt.

317 are only 1.5a, at least a 350 for double that (this is per lane, not for entire track) and should suffice for 1/32 cars and a 338 is 5A

 

shouldn't be any issues at that range. Heatsink and all is well

 

(edit: 15?? how many lanes? 317 and a 3055 per lane (3-4A per 3055))

Edited by gzminiz

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Dick Smith sell another one which is 3-30v 20amp but it is a switch-mode power supply. What is so bad about switch-mode power supplies? Most, if not all, of the power supplies I can source now are switch-mode.

 

I know switch-mode means that instead of dissapating the excess power is turns the input on and off as needed but I can't see how that would affect the output that much.

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QLD:- Calamvale DSE, Carindale DSE, Dalby DSE, DSE Bundaberg (FRN), Gladstone DSE, Hervey Bay DSE, Kingaroy DSE, Maroochydore DSE, Toowoomba DSE, Townsville Powerhouse, Victoria Point DSE, Warwick DSE, Yeppoon DSE

 

All are showing stock. I had the same answer down here BUT found two stores still with them.

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Dick Smith sell another one which is 3-30v 20amp but it is a switch-mode power supply. What is so bad about switch-mode power supplies? Most, if not all, of the power supplies I can source now are switch-mode.

 

I know switch-mode means that instead of dissapating the excess power is turns the input on and off as needed but I can't see how that would affect the output that much.

 

Well, depends on how fast it switches. The faster the better. Kinda imagine if you were to run your car at WOT then slam it close and smash it open and slam it closed constantly just to maintain 60kph as cruise through your neighborhood. Ends up killing your motor a lot quicker and uses a heck of a lot more petrol.

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Here are the specs:

 

Ripple & Noise: 50mV peak - peak

Load regulation: 200mV typical (0 - 100% DC load)

Line regulation: 50mV typical

 

@kalbfellp: Rang around the three closest ones on that list and none have them in stock. The others would require a lot of driving (1+ hours) which would use up to much fuel.

 

Edit: Reading around, I've seen conflicting reports on where it works for some, doesn't for others. Seeing as it's the only one with 15+ amps and variable voltage that I can get in my area, I may just have to go with it.

Edited by Denney

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Denny,

 

a switch mode power supply may work just fine. it is impossible to make a blanket statement in that regard. I probably should have not confused the issue. A switchmode supply refers to how the voltage is regulated. Usually the regulater is swithching the bulk unregulated DC power on and off to charge up the filter caps. If anything could be a problem, it could be the no load condition. A few 12 volt track lights connected would take care of that if it was a issue.

 

Switchers are particularly useful where you need several secondary voltages. You use a primary of a transformer in series with the large filter caps. A multi tap secondary can then provide various voltages higher or lower than the original rectified bulk DC voltage. Perfect for things like a computer power supply.

 

My experience with switchers was in designing them for a specific piece of equipment, with known current draws for each voltage. In a fly back switcher, the current available on secondary voltages is reliant on the primary voltage drawing sufficient current. Typically, the primary voltage needed to be loaded in the range of 10%-90% for the secondary voltages to work.

 

I much prefer a lab type supply with a lot of current capability and solid regulation. I use three HP 6286A lab type power supplies. I bought them on ebay for between 60 and 80 dollars each. They are brutes and rock solid, 0-30 volts at 10 amps. Remote voltage sensing, I dont use it and adjustable current limit with a meter for voltage and for current. To me, they are just about the perfect slot car supply, front and rear connections as well.

 

My Craperra wall wart, would float to over 18 volts with no load. With a mild RTR car under full power, it would drop to around 11 volts. You get used to it. when I first drove with my big supplies, the cars felt dead at low throttle. This is because of that high no load voltage of the unregulated carerra supply. ten minutes of driving and I couldnt tell the difference.

 

Sounds like guys have some potential other solutions for you. keep a eye on ebay in the industrial listings, I forget the exact place, but you can get to electric and electronic test equipment. I think there is even a topic for power supplies.

 

post pics of your track, we love pictures.

 

j

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So the voltage could spike up with no load on a switch-mode power supply (or the voltage would spike down under load?)?

 

Say I bought the 13.8v / 20amp power supply... does that mean that the 13.8 WOULDN'T be regulated with no load? At the moment my understanding is very limited and to me it seems like a switch-mode power supply is opposite to what a regulated power supply would achieve. Arghhh.. damn electronics.

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Switch mode supplies "adjust" the voltage in very short time periods, to provide regualted/stable voltage under varying loads.

 

I have heard from some electronic techs that the smoothing provided by switchmode supplies IN THEORY may cause incremental harm to some motors, but most of our home tracks use switchmode supplies, as did our old club track which ran "magnet sleds", and up to 12 amps draw on a supply rated at 25 amps. This was a during a period of a little over 2 years.

 

I use the same supply at home. We never found any problem with the supply, we "dead shorted" it quite a few times and it made groaning noises of protest, re-set itself in a few seconds, and carried on as before.

 

We didn't have any motor failures we could attribute to the supply, and the ease, pprice and simplicity of using them makes them a very suitable option

 

(IMHO)

And remember, all these guys with highly sensitive RF ham radio equipment use them as standard these days .... and I think their demands are just a little more precise than a little brush based DC motors we use.

 

So I think you are perfectly safe going with it.

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I am/was a hammy. A cheap switch mode can cause damage as it doesn't switch fast enough. Nothing wrong with switchmode as long as it is decent. With that said how much damage is negotiable. Might be negligble for our normal use. I guess it is more the faster it switches the less the risk (and probably the better components inside too)

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Typical Dick Smith don't update their stock as they all had them still listed as in stock! Sorry.

Edited by kalbfellp

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It's all good. I ended up getting the 13.8v / 23a switch-mode regulated supply for Dick Smith. Came with a 3 year warranty to. :lol:

 

I tested it all out with the digital multi-meter I have any everything seems ok. It is adjustable from approx. 13 to 14.5 volts using a flat head screw underneath.

 

I swear I will post pics tomorrow. I didn't get much done today but tomorrow I want to finish routing the track and get it prep'd for paint.

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Ok guys, here are the photos I promised. I have only made 2 routing mistakes so far. Not bad for my first time ever routing. Tomorrow I plan to finish my routing and get the tables prepared for painting. I also ordered my Phidget 0/16/16 interface board for PC Lap Counter today. Should arrive by mid week. :D

 

Here's the trammel I used for the corners:

img_1936.jpg

 

Getting ready to start routing the tables:

img_1938.jpg

 

All the corners routed, time for the straights:

img_1947.jpg

 

Painting the test piece. Turned out rather well:

img_1953.jpg

 

The power supply I settled on:

img_1954.jpg

 

As usual, more photos in the gallery.

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IMO the 13 volts might be too much on such a short tight track,you will probably need spme heavy cars. We run up to 13.2 on my 65' track and our cars are uo to 130 grams. We are now running at 12 volts for most class's as the DUPR is run at 12 volts.

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We used to run cars up to 150g on the last track at 13.8v. This track is longer but tighter instead of shorter but more flowing. Hopefully it works out alright. If not, well, I'll work it out when the time comes. :D

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Sorry for the lack of updates but I've just been so sidetracked with this track. Basically I've managed to turn the hunk of MDF into a functional slot car track. I painted the slots white for lane 1 and red for lane 2. I then painted the table top and then taped up the lanes.

 

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I had planned to make my copper tape laying thingmabob but it didn't work out as planned so I laid the tape manually. It was actually quite simple and quick and it meant that I had one piece of copper tape running the length of the track. There are a total of 12 power taps around the track. A little overkill but if the tape breaks on a join between the boards, it won't be an issue.

 

img_2008.jpg

 

The wiring is all labelled underneath the table and each power tap runs to a central core of 4 wires running back to the front of the board. These wires will then connect to the controllers, relays and switches. The Phidget board arrived the other day and I gave it a quick test on my PC and it works perfectly. I bought a cheap computer off eBay tonight so I should have a PC running sometime next week.

 

img_2012.jpg

 

For now, I've hooked up the controllers temporarily so I can test the circuit. It runs quite smoothly after the first few laps of getting used to it. I much prefer it to my last track. As usual, more photos on my blog and gallery.

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Presenting Warril Park Raceway!

 

img_2053.jpg

 

The last few days have seen the track completed and lap timing working a treat. The track times are around the 9 to 10 second mark but there is plenty of room for improvement on those times.

 

Here is the Phidget interface I have been talking about:

 

img_2019.jpg

 

img_2024.jpg

 

I mounted the Phidget card along with power control and the relay to what I call the computer control plate:

 

img_2038.jpg

 

I then built the 4 controller stations (2 per lane). There is a direction switch on each one along with a brake on/off switch. I would like to replace this switch with a rotary switch at some point. The reason for two controller stations is so that you can control a car in either lane from either end of the table. It makes marshalling much easier. Doing this also required a switch panel at the computer control station to select which controller station is in use.

 

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I added a track call button to both sets of controller stations. Here is an overview of the computer control station:

 

img_2055.jpg

 

The light bridge is an infra-red based sensor system that is hooked up to the Phidget input. I added 10 LED's to the top (5 red, 3 yellow and 2 green) to indicate various things like low fuel and first place etc.

 

img_2049.jpg

 

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With that done I can work on the little scenery I plan to have. I want to break up the board by having lines marked on the sides of the road and grassy areas painted. I also want to hook up track lighting at some stage.

 

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The next thing to do is to tidy up some of my wiring and possibly rebuild the controller station boards to be a little more, um, stable. They tend to bend quite a bit at the moment when pushing the controller plugs in and out. As usual, more photos in my gallery.

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Hey guys, tonight I painted the grass areas around the track. They look OK for now but will look better once I get some scenic stuff on them (something like Woodland Scenics). I will do the ripple strips tomorrow as I'm still a little unsure as to the best way to paint them.

 

img_2071.jpg

 

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I also bought a whole bunch of stuff from Jaycar today because I want to re-model the drivers stations. I have the new fuses ready to be wired in and also have a couple of rotary switches and a stack of diodes for the adjustable power (choke?) and adjustable brake.

 

I found a cheap sound card and put it in the lap timing PC so we finally have some noise other than the motors! I'm also considering Ultimate Racer 3.0 over PC Lap Counter. Mainly due to the car maintenance and detailed statistics and history features. It's also a little easier to use.

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Congrats on a job well done Denney,tight winding circuit would be nice to drive on.Cheers colin.

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Hi Denney

can i offer some advice please

I would not use the male 3 pin electrical plugs if I were you . too easy for little slot racers to you plug hand controllers into a GPO (general power outlet).

Clipsal do a recessed outlet plug with male pins that sit in a escutcheon that would almost be flush with with thw side panel. price about $12-15 available from most electrical wholesalers.

Here's a link, scroll to bottom of the page

 

clipsal webpage

these are a almost universal fitting at most commercial raceways and many hometracks

Cheers Al

ps Oops I just notice you're using round earth pin plugs.

Edited by lenny broke

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@lenny broke: I made sure to get the round earth pin to prevent those issues and the local commercial tracks around here use those plugs as well so it's all good.

 

I've completed the ripple strips now and the track is really coming together. I had to screw the borders on because glue and nails didn't stop them from popping off when people continually lean on them.

 

img_2074.jpg

 

The ripple strips are paper stencils rolled on with white paint. I then used red enamel with a foam brush to draw on the stripes. The enamel gives the strips a rippled effect and contour that works nicely. Once they get a little worn and dirty, they shouldn't be so glarish...

 

img_2081.jpg

 

I also gave the track some identity with writing on the light bridge.

 

img_2075.jpg

 

Next up is the new remodeled drivers stations and clean-up on the wiring. I hope to have it completed by next weekend and get the computer set-up with the track, drivers and cars so we can start keeping some of the stats. I managed to pull a 7.710 tonight which is down from the 9.9 that we started with. Very pleased.

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