# Switch-Variable Power Supply



## christos_s (Jan 16, 2008)

If you are slot-experienced and a little electro-mechanically literate please reply.
Why do people consider only expensive, over $100 variable power supplies?

There are plenty of switch regulated (ok not continuous-variable) power supplies around 24-40Watts in the 25-40 euros range = $37-60, lately especially with the proliferation of gadgets, laptops etc. and the need of flexiblility.

After all the original AuroraMM was only 24W (= 1.2amps at 20V) and the new BSRT also 24W (= 2amps at 12V)

The pictured power supply below is 36W (= 1.8amps at 20V or 3amps at 12V) and the switch allows operation in steps between 5-24V at 26.50euros=$39.25


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## martybauer31 (Jan 27, 2004)

I think perhaps it's because they are sometimes equating more money with higher quality (which admittedly, sometimes they are very correct), but also a lot of guys on here race the high end magnet cars and they need more than just a few amps for their track.

I found my variable supply that goes from 0-30 V with 5A for under $100 and it handles everything I run at it just great. But again, I am not running anything faster than a G3 super stock, so the 5 A has been plenty to this point.

FYI, looks like you posted this to multiple forums, you may want to drop one so you have people posting to just one.


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## christos_s (Jan 16, 2008)

the 5A are at what voltage? How many Watts or VA is it?


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## martybauer31 (Jan 27, 2004)

it's variable, it can be at 5A at anywhere between 0 and 30V.


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## christos_s (Jan 16, 2008)

No it cant Marty, basic electricity physics knowledge.  sorry...

Check its specs usually printed on it. Somwhere it lists VA or VmA or Watts

You divide that by the selected voltage and you get maximum current in Amps


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## martybauer31 (Jan 27, 2004)

I'll alert the manufacturer that what they have done is wrong then. My supply is dialed to 5A whether it's at 5V, 12V, or 30V and it works just fine.


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## christos_s (Jan 16, 2008)

There is a separate dial for Amperes? usually just a switch for Volts 
Did you check for Watts or VA (VoltAmperes) or VmA(Volt-miliAmperes) rating anywhere on the casing?
You can also check the technical specifications sheet


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## mking (Apr 25, 2000)

*$100 power supplies*

i may be wrong, but i think one reason these cost $100 instead of $40 is that they are desgined to output a constant amount of amps even if you change the voltage. less expensive adjustable power supplies will reduce the amount of amps as you increase the voltage. that means the more expensive supplies draw a variable amount of watts, which probably means a more complicated design, meaning inceased costs. 

but what do i know, i am a chemist, not an engineer. 

http://cgi.ebay.com/NEW-PYRAMID-5-A...ryZ48708QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


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## Xence (Oct 2, 2007)

hey Mike, so is that pws a good one for an HO setup or is it some piece of junk? I know that company used to make amplifiers for radio shack back in the day. I had no clue that they also made pws'.

Reason I'm asking is that I'm in the market for one. I just got my track all setup and am still working off the wall wart's and would like to change to something where I can adjust the voltage for kids and people that have no clue how to drive these cars.

Cheers,
Xence


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## christos_s (Jan 16, 2008)

Aaaa, well these models are basically for labs. They have more complicated circuitry to regulate voltage OR current.
In this case the maximum output is 5X30=150 VA. Its also more expensive to have truly variable regulator rather than switches which fixed increments.
But then again what do I know, I'm an architect...

The basic question is what I originally propose enough for stock cars. I dont want to run race cars with rewound armatures or other power demands, but I do want to regulate voltage to adjust the response range from controllers to cars


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## mking (Apr 25, 2000)

*power supplies*

hi glenn

ive been looking at the pyramid power supply for a while, but havent bought one yet. i think they are a pretty good deal.

the gold standard is an MG power supply, 0-20 volts and 0-10 amps. 

http://cgi.ebay.com/MG-POWER-SUPPLY...R-NEW-HOT_W0QQitemZ330177947425QQcmdZViewItem

alan galinko sells them for $125 plus shippig, so about $150 total. 

i have one of this, and have never had any problem with it. its dedicated to a 6 lane track. 

10 amps means you can have power a 4-6 lane track with modified magnet cars that draw alot of current

the pyrmaid is 33% ($50) cheaper, and 5 amps is plenty for a four lane track unless you plan on running magnet cars with really strong magnets and hot arms. i am considering getting one for a smaller track. 

i also have one of these, and it works fine. 

http://www.omnitronelectronics.net/...ngle-variable-power-supply-0-30VDC0-2AMP.html

i do wish id spent the extra $15 and bought the next model up, with 5 amps and not 2 amps. thats why i am looking at the pyramid, i think the 2 amp supply is not enough for the 16 foot maxtrax. the specs for the pyramid 5amp model and the mastech 5 amp model are similar, and the price with shipping in about $100 for both. i think the black pyramid unit looks nicer than the whte mastec unit.


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## [email protected] (Jan 25, 2007)

I have had the MG (PS 10-AD) 20v 10a for a year now. Great, clean, adjustable power and plenty of amps for polymods or whatever. No problems. Definately worth my $150.00 mj.


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## Xence (Oct 2, 2007)

Think I'm going to have just pony up and get the 10amp piece. I don't want any problems or in the future I figure out that I would have been better off getting the higher end unit then I'll be kicking myself in the end.

Cheers,
Xence


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## Slott V (Feb 3, 2005)

That small wall pack would probably work for stock cars on a small layout. It's a little more powerful than a stock wallwart. They just don't have enough "umph" for large layouts and more powerful classes of HO cars.

On the subject of amps: There is a big difference between amps and volt amps (VA). Also another thing to pay attention to in the larger supplies is constant amperage and peak. I have a Lambda 0-30 v adjustable with 10 amps _peak_ and 7.5 amps _running_, depending on the output voltage.


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## Xence (Oct 2, 2007)

Slott V has it right. RMS value of any _peak_ value is multiplied by .707 thus your 7.5 amps _running_ as SlottV has pointed out.

Cheers,
Xence


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## SwamperGene (Dec 1, 2003)

Alot gets overlooked in these discussions about Amperage. It's about more than just running high-end mag cars. The first thing I noticed when I went to 10A regulated on 4 lanes was with my T-Jets, besides a noticable "feel" in power...you could put 5000 laps on a car and take it apart to find it's darn near as clean inside as when you built it. Rails get less black oxidation, shoes stay cleaner. Brushes last longer. Rail connections are better. The list goes on. To me, this is the stuff that makes it worth it.


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## AfxToo (Aug 29, 2003)

> There is a big difference between amps and volt amps (VA)


The VA rating of a power supply states the maximum power that the power supply can source. The VA rating tells you that the product of voltage times current can never exceed a certain value, the VA rating. The VA rating is usually accompanied by a maximum voltage and a maximum current rating, which may further constrain the output, but typically the VA rating is the hard limit and you usually can't get maximum voltage and maximum current both at the same time.

The difference between nominal or steady state and peak output on a power supply has to do with component power ratings, not RMS versus peak voltages. Think about it, RMS... DC...


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## donster (Dec 13, 2005)

SwamperGene said:


> Alot gets overlooked in these discussions about Amperage. It's about more than just running high-end mag cars. The first thing I noticed when I went to 10A regulated on 4 lanes was with my T-Jets, besides a noticable "feel" in power...you could put 5000 laps on a car and take it apart to find it's darn near as clean inside as when you built it. Rails get less black oxidation, shoes stay cleaner. Brushes last longer. Rail connections are better. The list goes on. To me, this is the stuff that makes it worth it.


Exactly right. One thing that gets overlooked when talking about power supplies versus wall-warts is filtering. A regulated power supply includes a good amount of filtering which reduces the AC component (known as ripple) on the DC output. The better the filtering, the closer to pure DC you'll get on the output. The better the regulator circuitry, the less the output voltage and current will vary under a changing load. And a slot car presents a constantly changing load. That's why many racers will spend a few extra bucks on a good regulated power supply. It approaches the pure DC of a battery yet has the convenience of being able to adjust the voltage and current output.


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## AZSlot Racer (Dec 5, 2007)

So for a 4 lane track you need at least 4 amps? Am I reading that right. I see alot of 0-30V power supplies @ 3 amps, I'm assuming these are not ideal especially if you anticipate getting some higher end cars, is that right?
Thanks


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## mking (Apr 25, 2000)

*2-3 amps vs 5 amps*

on this website, a 0-30 volts 0-2 amp power supply is $65

a 0-30 volts 0-3 amp power supply is $75

a 0-30 volts 0-5 amp power supply is $80

i am still kicking myself for cheaping out and buying the 2 amp unit. 

$15 for the difference between 2 and 5 amps ought to have been a no brainer.

a $5 difference between a 3 amp and a 5 amp power supply really is a no brainer. 

i think you would be much better off with a 5 amp unit for a 4 lane track, if you dont want to spend the extra $50 or so for a 10 amp unit


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## Slott V (Feb 3, 2005)

Ya I have to agree with Gene on the part about cleaner cars, comms, and the reduced oxidation on the rails and black filth in the connections. I used to run double Tomy wall packs on each lane of my 4 lane layout and swore by it for years. -Until I bought a filtered supply, boosted the wire guage to all feeds and starting using much heavier switching and controller hook ups. MAJOR difference. Very noticable. Cooler running motors. And of course better acceleration in the straights. And we really don't run much hard core stuff. A few Super Stock class SG+, maybe a few G3 modifieds now, but for the most part, relatively stock SG+ and Tyco hard bodies.
:thumbsup:

For guys just getting started and experimenting with large layouts, you can certainly get by with a couple of wall packs, some added power feeds and the stock controller hook ups. You will enjoy racing HO's much more as you boost the power capabilites at every area, but the fun factor will still be there with lesser grade power supplies. Its just like building real hot rods; Its never enough power. More power, ugh, ugh, ugh!


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## Xence (Oct 2, 2007)

ok so what are most people running concerning pws'? I just looked at the site mking had put up and that does look fairly decent. Is this a good unit? Is it junk? Thoughts/opinions are welcome here. I'm running a 4lane tomy track. I have maybe 2 or 3 of the wizzard style cars right now and I don't run them too often.


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## christos_s (Jan 16, 2008)

I just ordered a switchable 15 / 16 / 18 / 19 / 20 / 22 / 24V regulated DC, 72Watt (3A @ 24V) or (4.8A @ 15V) power supply. You cant adjust the supplied current only the voltage at stepped intervals. Yes I opted for a stronger ps with less selections than the original post. It cost me 27euros=$39.20

I dont see the need to adjust current the cars will draw as much current, unless they top the supply, which is unlikely for this configuration. Adjusting the current below the car demand will act like a cut-off point basically affecting the top speed (anyone out there verify that?). Controllers are current regulators with VARIABLE slide resistors. While with voltage regulation from your power supply you get a whole new range for your controller trigger. 

To complement this (already with my existing ps) I have added a switch to my parma resistor-controllers that adds inline resistance to the circuit, reducing the supplied current. Flipping the switch is like shifting gears. Lower in the bends, overdrive in the straights. I'll photograph that and write an article soon...

Till now I was using a standard 1970 AuroraMM 24VA ps supplying nominally 20V, measured 21V


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## christos_s (Jan 16, 2008)

donster said:


> ...
> The better the regulator circuitry, the less the output voltage and current will vary under a changing load. And a slot car presents a constantly changing load. ....


Yes, if the power supply is ample the voltage should not vary just the current.
The current varies according to circuit demands. If the ps is weak and it can't cope voltage will drop. (and the ps and motors will overheat)

Any professional electricians out there ?


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## Grandcheapskate (Jan 5, 2006)

SwamperGene said:


> Alot gets overlooked in these discussions about Amperage. It's about more than just running high-end mag cars. The first thing I noticed when I went to 10A regulated on 4 lanes was with my T-Jets, besides a noticable "feel" in power...you could put 5000 laps on a car and take it apart to find it's darn near as clean inside as when you built it. Rails get less black oxidation, shoes stay cleaner. Brushes last longer. Rail connections are better. The list goes on. To me, this is the stuff that makes it worth it.


 But when is enough amps enough? If the requirements of your car(s) is no where near 10 amps, let's say it's less than 5 amps, what does the extra 5 amp capability buy you?

I have a four lane layout set up but I am the only one who uses it (at least so far). So there is only one lane in use at any one time and I don't use anything hotter than a Tyco 440-X2, Lifelike or Tomy. In a case like this, would a 10 amp supply give me any advantage over a 5 amp unit?

Does running a power supply near it's upper limit have any drawbacks? Years ago I remember guys telling me that you wanted to buy a stereo with as many watts per channel as you could afford. It wasn't that you were going to use all that power, but it made the sound crisper at lower volumes because you were running the amp much lower than it's maximum. The less the amp had to work, the clearer the sound. Does the same thing apply to power supplies?

Thanks...Joe


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## SwamperGene (Dec 1, 2003)

Joe if you are the only one using it then I think 5 would be sufficient. Here's a stupid little very low-tech test though, as it's something I notice on well-powered tracks...will a good Tyco with some low (like 434) "A" SuperTires still break traction from a dead stop? That's the power showing itself. 

The stereo analogy isn't bad, 'cept in our case the "distortion" is seen as heat.

Scott also brings up a good point with wiring...gotta pay attention to the details. Make sure all switches are rated high enough. Running a good 10 or even 8 AWG pair from the PS to wherever the lane wiring splits off is also a good idea...remember that up to that point power from all 4 lanes is flowing through the same wires. From there, I use 14 AWG throughout, with grounds running fully back to the junction, not tied together anywhere else.


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## Xence (Oct 2, 2007)

I'm going to re-iterate my previous question only because I'm kinda getting to a point now where I need to pick up a power supply soon and I need to take a hard look at some stuff.

Would someone please name out or post a web address where I can pick up a power supply that will do, which is VERY similar to what grandcheapskate has, 4 Tomy AFX lanes and for the most part outside of about once a week I run pretty much by myself. My buddy micyou3 and I run on the weekends but outside of that I'm pretty much on my own with all 4 lanes. I want to say christos or someone posted this link earlier in this thread: http://www.omnitronelectronics.net/...pply,[email protected]

Is that a good unit? Is it garbage? Is there something comparable? Is there something cheaper out there? More expensive? If more expensive, why?

Thanks for reading my insane diatribe.

Cheers,
Xence


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## SwamperGene (Dec 1, 2003)

$30 more, and worth it:

http://www.hodra.org/ag&gProducts2.htm


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## AfxToo (Aug 29, 2003)

The $99 unit being sold by TrackMate under clearance is a good unit for sure and usually sells for much more. I'm not sure about the blemished status, that's something you would have to decide whether you want to accept. 

http://www.trackmateracing.com/shopdisplayproducts.asp?id=17&cat=<b>Power+Supplies</b>

The MG unit Galinko and Professor Motor sell are fine too. That's what I use for my home track.

http://www.professormotor.com/cat_wiring.shtml
http://agg.fsmra.com/aggstore/


The unit you linked to is fine too. A 5A unit will work well for home racing. Don't sweat it.


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## mking (Apr 25, 2000)

*hi glenn*

options:

#1. The AG&G MG 0-20 volts 10 amp unit, $125 + shipping = about $150. I own one, works great. 

#2. Mastech 0-30 Volts 5 Amp from Omni electronics. This website is odd, in that they often have similar products for different prices. this one is $10 less for the same spcecs compared to what you posted

http://www.omnitronelectronics.net/...ower-Supply,[email protected]

so $79 + 19 shipping is just under $100. i own a 2 amp mastech and it works fine. the cases are plastic, not as rugged as the MG, but your not really going to be hauling it around alot. 

3. The unit from Trackmate (the blems) are also Mastech, 10-28 volts 10 amps, and should be fine as well. $99 plus $28 shipping in about $130. 

4. A Pyramid 0-30 volt 5 amp unit from Ebay for $90 including shipping. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=160206074556&ssPageName=STRK:MEWA:IT&ih=006

i think Jeff aka Scafremon uses one of these. I think the casing is metal, and i like the analog meters insted of the digital meters. 

Any of those 4 will work, and work well. The cheapest 5 Amp supply is $90, the cheapest 10 amp is $130. its up to you whetehr you want to use the $40 to buy more cars or controllers now. if you plan on eventually having a 6 lane track, or plan on racing modified magent cars, you would be better off getting the 10 amp. 

good luck!!


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## brandX (Nov 25, 2006)

Buy the 10 amp. If you ever have more than one person over it's worth it! The clearance one from Trackmate is a good comprimise.


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## Xence (Oct 2, 2007)

Excellent info Mike. I have no desires to run the crazy magnet cars, not deadset against just not really my cup of tea. Truth be told (ssssshhhh ... don't tell micyou3  ) I can see micyou3 and I getting into the fray cars. I'm enjoying that funjet you sent me so far. He keeps trying to get me into the t-jets and I'm getting to a point now where I think I can see the light of day on this. I've always been an A/FX guy but hey I'm not against trying new (old) things.


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## micyou03 (Apr 8, 2003)

Xence said:


> Excellent info Mike. I have no desires to run the crazy magnet cars, not deadset against just not really my cup of tea. Truth be told (ssssshhhh ... don't tell micyou3  ) I can see micyou3 and I getting into the fray cars. I'm enjoying that funjet you sent me so far. He keeps trying to get me into the t-jets and I'm getting to a point now where I think I can see the light of day on this. I've always been an A/FX guy but hey I'm not against trying new (old) things.


I'm listening. And I like what I'm hearing. (reading)


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## lolagt (Sep 19, 2006)

the more amps you have the cooler the cars run .if you run hopped up cars they draw more amps. the amps push the current.on a big lay out the more amps the better. back in the day the hobbie shops all used deep cycle batteries. that what i use 18 volts and over 200 amps on 75 feet of 4 lane track i can run any thing from t-jets to fully blown neo cars.


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## Xence (Oct 2, 2007)

I called Alan at AG&G for one of the $125 power supplies.... No dice. He doesn't have any nor does anyone else at this point. He told me he is supposed to be getting some in another month or so. Any other alternatives here that anyone can suggest?

Cheers,
Xence


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## Hornet (Dec 1, 2005)

http://www.infoserve.net/oss/slotcar/ps.htm


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## Xence (Oct 2, 2007)

Sweet. I'll be calling this guy before too long here today. I need to pick one of these up before I blow my slot car money on something else like.... more cars. 

Thanks for the link Hornet

Cheers,
Xence


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## Xence (Oct 2, 2007)

Any other suggestions? I called Trakmate to no avail. Wow this is nuts I thought for sure someone would have had something I could have purchased for use.


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## Hornet (Dec 1, 2005)

That's not good if he doesn't have any too,we just picked another one up at christmas time for one of our club tracks,looks like we were lucky then.
Hopefully somebody'll have link to a good used power supply on e-pay


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## Grandcheapskate (Jan 5, 2006)

lolagt said:


> the more amps you have the cooler the cars run .


 Can someone expand on this? I can understand why a car would run cooler with a full rectified power supply; getting power smoothly has to be better than getting it in spurts. But if you have a power supply which generates enough amps to handle the demand, what advantage is there is having a supply that provides more than that?

Also, even if a car wants more amps than a power supply can produce, why would that generate heat? Wouldn't the car just run below it's potential?

Wouldn't this be somewhat equivilent to hooking up a fire hose to your indoor plumbing? Although the hose can take a lot of water (amps) and pressure (voltage), your source can't supply it. The hose isn't any the worse for wear, it just isn't used to it's potential.

Now, hook your garden hose to a fire hydrant and open it all the way and your probably going to need a new hose.

Thanks...Joe


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## donster (Dec 13, 2005)

*Epay Power Supplies*

(Note: I have no monetary interest in any of the following items. For reference only.)

Check out these - Item number: 200200329157
 Item number: 350025688438
 Item number: 350026175111

Looks like the same guy has three of them. I had one of these units. It is a nice supply and would work well for slots. Only thing that you might not like is that it has a fan that runs whenever the supply is on. It's not a loud fan but it could be annoying if you don't like fan noise.

Here's another one - Item number: 310021807763

It looks to be an older unit but it's a Lambda (good quality) and military surplus so it's built to military specs.

Yet another possibility - Item number: 250215821605

Excellent lab quality, only a 0-20V unit but it is 0-20A unit. If you can get it at or very close to the listing price, even with shipping it comes in at about the same price as a new 10 Amp unit from some of the previously mentioned links.

As always, these are used units and you can only go by what the seller claims as far as functionality. But if you're at all electronically inclined you might just get a decent bargain.

I'm sure there's probably more usable supplies on Epay too. Just have to dig a little.

You might try searching the web for new supplies too. Might be some comparable new gear out there as well for a decent price.


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## TK Solver (Mar 18, 2004)

This guy http://www.davesmodelracing.com/parts1.htm built me a nice little system including a fused 4 Amp 0-30 volt filtered/regulated power supply and distribution box with Tomy terminal connections. I'm very pleased with the results and the price was very reasonable. Give him a try.


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## donster (Dec 13, 2005)

Grandcheapskate said:


> Can someone expand on this? I can understand why a car would run cooler with a full rectified power supply; getting power smoothly has to be better than getting it in spurts. But if you have a power supply which generates enough amps to handle the demand, what advantage is there is having a supply that provides more than that?


Basically there is no advantage to having a supply that provides a LOT more current than is needed to run the car(s). Although, having a little reserve above the exact current draw of the car(s) is somewhat advantageous. The unused capacity of the power supply is just that, unused.



> Also, even if a car wants more amps than a power supply can produce, why would that generate heat? Wouldn't the car just run below it’s potential?


A plain old regulated supply will try to deliver all the current that your car is calling for until the fuse blows or some other means of internal protection circuit activates. Running a plain old regulated power supply at its maximum capacity for any length of time will generate heat. How well the supply deals with the heat is a function of its design. A constant current power supply will deliver an amount of current up to its maximum setting and will not try to deliver any more. These will also generate heat and the design of the cooling system will allow these types of supplies to operate continuously at full output. 

And, yes, the car would operate below its potential with an undersized power supply. Whether the car will run hotter is debatable. Whatever electrical energy is not converted to motion will be dissipated as heat. If the energy supplied is less, it won't run as fast and should have less heat to dissipate. There may be other factors which cause the car to run hotter at lower power such as possible inefficiencies of energy conversion to motion at lower armature speeds which is just too complicated to get into for this hobby.

Here's a good experiment for someone with one of those infrared non-contact thermometers. Maybe they can take a few measurements and monitor the temperature of a car after 20 laps at full power and compare it to 20 laps at 75% power, then 20 laps at 50% power, etc. and let us know the results. Of course, they'd have to let the car cool down to room temp before each run so that the starting temp was always the same. I'm sure the results would be interesting.


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## AZSlot Racer (Dec 5, 2007)

I've been running 13.8v on a 34' 4 lane and it is plenty of power. I have mostly magnet cars and your deeper into the controller but seldom wide open, the AW cars I have still spin their tires relentlessly. I'm adding a 5k pot to dial it down for the kiddos, maybe I'll put a gauge on to see what voltage they can drive at.


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## mking (Apr 25, 2000)

*Answer to the 5 Amp vs 10 Amp question*

MartyB hosted a race today (thanks marty!). We raced G-Jets and G3 Superstocks (similar to Tomy Super G+ with ceramic magents) on his 4 lane 12 foot Brsytal routed track. 

Marty has one of the Praymid 5 Amp variable power supplies weve talked about on this thread. It had trouble with the super stock race. Basically, at the start of the race, the draw from all the cars going from a cold start exceeded 5 Amps and the power supply tripped. We figured a workaround, at the start of each heat someone stood next to the power supply to hit the reset button. Once the cars were moving, the peak load dropped and the power supply provided plenty of power for racing. 

I was pretty surprised. I thought the 5 Amp supply would have been sufficient for all but polymer or neo cars, but i was wrong. 

Damn. i wanted to save the $50 difference between the 5 Amp and 10 Amp unit.


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## martybauer31 (Jan 27, 2004)

Yep, it surprised me as well Mike. I never even figured it would have been an issue as we have had 4 super stocks running at the same time in the past, but never 4 of them cranked to full speed out of the gate at the same time. Once the cars were going it never peaked over 3.5 Amps.

So I guess the moral to this story is, if you plan on running the high end super fast cars, maybe this power supply isn't for you. If you are happy running t-jets, and magna-tractions and super g+ cars, then this one will fit the bill. I have to say I am not planning on running out to get another P/S anytime soon, this one works fine for the 99.9% of the time when I am running G-Jets, fray cars, and the other odd variety of car we happen to break out.


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## Dslot (Sep 2, 2007)

*Pot vs. diodes vs. rheo*



AZSlot Racer said:


> ... I have mostly magnet cars and your deeper into the controller but seldom wide open, the AW cars I have still spin their tires relentlessly. I'm adding a 5k pot to dial it down for the kiddos ...


Rather than hijack this thread, I started a separate Voltage Adjustment thread to handle the question of how to adjust the input voltage to get best response from different car types with the same controller. Please check that out if you're interested or could help answer the pot vs. diodes vs. rheo question. -- D


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## fly0nthe_wall (Mar 23, 2008)

Actually, we are getting 'peak' (as applied to AC) confused with 'peak' (as applied to LOAD). Peak Load is talking about how much current you can draw for a short period of time (usually due to cooling or filtering limits). With a DC power supply, we are concerned with Peak Current Load and Running Current Load. For sudden starting of cars (or coming out of turns) the current demand will increase. That would be Peak, and wouldnt generally last too long. So, a power supply like SlottV is talking about would provide 10A for short periods of time, and 7.5A for continuous periods.


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## AfxToo (Aug 29, 2003)

Most power supplies will not trip if the current demand hits peak for a short period of time. They will simply clamp the current at the max value unless they have additional protection circuitry that kicks in after some period of time do to heeat related concerns. The very short spike caused by four cars starting from a stop should not have popped the protection circuitry because it lasts just a few milliseconds.


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## T-Jet Racer (Nov 16, 2006)

I am going with the pyramid, if you compare it to 2 wall worts for a 4 lane it has to be MUCH better. Astron is the better brand, I have had both with my amature radios and the pyramid did not hold up to the abuse ( 13.8 @30 amp supply not the variable volt ) but for this duty should be great!


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