Large Scale Central

Loco power draw

Electronics Power and Sound
#1

In his review of the Dash-9 (see Reviews), Terry speaks of running four locos simultaneously as follows: “They moved smoothly and with great presence around my tiny pike, first one, then two, then three and finally all four together - drawing, according to the meter, a total of a measly 4.5A while doing it…economical AND efficient at the same time.”

My understanding is that the three-axle USA Trains models (S40-2 and Mac) draw considerably more power. Does anyone know if this is true?

If you’re asking yourself, “Why does this bloke want to know THAT for?”, it’s because:
a) I’m just getting to the stage where I’m looking at buying locos and rolling stock;
b) Terry’s review impressed me to the point where I’m re-evaluating my bias towards US Trains locos and am seriously considering a Dash-9;
c) I am also in the process of evaluating transformers (would love radio, but that’s another story - ain’t gonna happen), and loco power draw is relevant.

I live in Perth, Western Australia, where the power is a nominal 240v but is actually more like 253v. Depending on the suburb, the weather and whether or not bananas grow on trees, spikes and brown-outs are all-too-common occurrences. I proved that once by calibrating a big APC UPS into a tight range before a hot week-end. The smell on Monday was YUMMY!

#2

I have the Aristo sd-45 which has the same motor blocks as the Dash-9.

Current draw is the lowest with no load on the engine.

These motor blocks will draw much more power when hauling a load. Your 4.5 amps will double if you pull a lot of cars plus addin some for grade/curve loads.

Note tht a friend has the PA ABBA set and he had to go to a 25 amp supply as he has a few cars with lights.

#3

Thanks, Dan. Do you know the kVA of your friend’s 25 amp transformer? That is, what’s the voltage @ 25 amps?

Terry’s measurements suggest a single Dash-9, on its own, not pulling any wagons, is likely to draw < 4.5 amps, possibly as low as 1 amp. I wonder if I could use a small LGB 22 kVA transformer/controller for a small train (e.g., <= 6 lightweight cars) pulled by a Dash-9 at a sedate pace on level track?

#4

Erm ,
Hesitantly , Dave , I must make a comment .
I don’t think you really meant to write kVA , 'cos that’s thousands of volts —22kVA would be 22000 volts .
I think you mean VA . Or Volt /Amps which equates to Watts . I know what you mean , it was just a typo , I suspect .

Mike

                        W                                  V                               W

PS
V I I R 2
I R

   For the benefit of anyone interested , the above squiggles are a very useful aide memoire when dealing with electrics . 

   Thus  from the first one W=VI , I =W        etc. 
                                                      V 
     
    and being an idle sod , I will let you work out the rest . just apply the same idea to each . W=Watts , I==Current , V =Volts ,R=Resistance 

     If you feel insulted by this suggestion , OK smartass . On the other hand , if you find it useful , glad to have helped . 

  Mike
#5

I personally would NOT recommend using any of the light weight power supplies with these large engines…Aristocraft or USAT. You will be disappointed in the end. That’s one area that just doesn’t pay to go cheap. Aristo’s 10 amp power supply with the Train Engineer is probably the best set up for the money. But don’t know if they make a version for down under.

#6

Insulted? Never! Just insulated. Yes, I was after the wattage. Any eye deers about other transformer characteristics I should look for?

As an LGB Jumbo is over ten times the price of one of their smaller units, I’m in no rush to jump in at the deep end. I know the Aristo Elite is dual 115-230, which will work Down Under even tho we’re 240. I could also buy a stepdown that will sit between the wall socket and any US transformer.

The advantage of going the stepdown route is that I can’t accidentally fry the thing by throwing the voltage switch to the wrong setting, something I encountered with a lab full of PCs a few years back. In the end, I Araldited the switches - but someone still tried . . . .

Mike Morgan said:
Erm , Hesitantly , Dave , I must make a comment . I don't think you really meant to write kVA , 'cos that's thousands of volts ---22kVA would be 22000 volts . I think you mean VA . Or Volt /Amps which equates to Watts . I know what you mean , it was just a typo , I suspect .

Mike

                        W                                  V                               W

PS
V I I R 2
I R

   For the benefit of anyone interested , the above squiggles are a very useful aide memoire when dealing with electrics . 

   Thus  from the first one W=VI , I =W        etc. 
                                                      V 
     
    and being an idle sod , I will let you work out the rest . just apply the same idea to each . W=Watts , I==Current , V =Volts ,R=Resistance 

     If you feel insulted by this suggestion , OK smartass . On the other hand , if you find it useful , glad to have helped . 

  Mike</blockquote>
#7

When you say what does a loco draw in amps, you need to qualify it by the conditions… running upside down on it’s back, on rollers, on straight track unloaded, on curves, on tight curves, under the load of X cars on level track, X cars up a Y% grade, stall with wheels slipping, stall with locked motor rotor, etc.

An amp draw measurement without any reference to the load on the loco is basically meaningless.

The big numbers for current you have seen is usually with the wheels slipping, or a “locked motor rotor stall” where you measure the current when the motor cannot even turn (while you overheat the motor and burn up brushes and commutator).

If someone is running a 25 amp supply, AND it COULD put out full voltage, say 24 volts, at that current (which is NOT the way people do VA, by the way), then it would have a kVA rating of 0.6, or 600 volt amps.

Like amperage draw without load conditions, VA is not a rating that gives you all the information, I have a 60 VA transformer that puts out 28 volts unloaded, it does NOT put out 60/28 amps at 28 volts. VA is usually rated at some specific voltage, although rarely published. Respectable (ok I’m opinionated) power supplies are rated at certain max current and power, especially regulated supplies, where they will say, specifically, 15 amps at 24 volts.

Regards, Greg

#8

Dave. Large power supplies of the type you mention are not readily available in Australia. The Crest Elite is a switchmode supply and as I understand it should be able to be used with our 240v AC mains power. Another way to do it is to gang a number of lower power switchmode supplies together in parallel. This can be done safely with some provisos. This:

will gang three 3.8 amp multi voltage supplies together and protect against back feeding with diode protection to power these:

To see how to do it go here: http://www.rcs-rc.com/titan/rcs_titan10v2-inst.pdf wiring diagram is on the last page.

#9

I often wonder why this keeps coming up , it is quite easy to get laboratory power supplies with ammeters and voltmeters built in .
I use them all the time , and get them from various sources like Tandy , Ex Military stores and so on . I also have a power unit with a built in true wattmeter , but have only ever seen the one . Which I bought . Army and Navy Stores .
Worth keeping an eye open for such things . They usually , being lab gear , have built in current regulation which can be adjusted ,thus useful for not blowing things up .

Mike

#10
TonyWalsham said:
Dave. Large power supplies of the type you mention are not readily available in Australia.

The Crest Elite is a switchmode supply and as I understand it should be able to be used with our 240v AC mains power.

…


Tony,

I had a big switching power supply for my HOm stuff - my friends were of the opinion that it was enough to power the Toronto Transit Company.
Bought it surplus from an outfit that cannibalizes mainframe 'puters. Was a bargain, too! :slight_smile:

#11

Grinning and shaking my head, Mike and Hans. You blokes are WAY out of my league in terms of technical know-how when it comes to power. My guess is you’ve forgotten more than I’ll ever know about it.

And that, amigos, explains Mike’s wonder about why this topic apparently comes up so often in the forums. It’s because most people are like me, NOT like U2 sparkheads!

To continue the Amateur Hour, I’m seriously thinking of importing something like a Bridgewerks 2-track controller and hooking it into a stepdown. For me, integration is important - I like the idea of power and train controller in one unit, just like the old Lionel ‘O’ gauge. David Sauerwald is the only one who’s actually answered any Email I have sent to the States re trains, and that counts with me.

I’d love to hear from anyone who knows a bit about Bridgewerks gear before proceeding further. I’ve read the comments on the Aristo Elite in other parts of this forum. They’re a mixed bag, and I’m a bit leery of a unit where I can accidentally fry the bacon.

Many thanks to all of you for the feedback so far!

#12

You are going to get mixed reviews on about any product in this hobby. It seems that it’s normal for one person to swear by a product and the next to swear at it. As for Bridgeworks, the only person I’ve known to have one was very unhappy with it. But let me set the record straight. His type of railroading isn’t the norm. In tonnage he tries to keep up with BNSF. 4 six axle locomotives and 100 cars running hours on end are his norm. That puts a lot of stress on everything. Aristo seems to hold up better for him. I’ve ran trains on his layout with the Bridgeworks and I’ve had no problems and found my trains responsive. I have also used their RC unit and quite frankly I think that sucks. It’s too sensitive to dead spots and the “key fob” style remote is too small for ease of use. Again understand that we are not talking about a normal back yard layout. My suggestion to you would be to make sure whatever you get…import or local grown, make sure someone there can service it for you. Sending something back to the US for service could put your layout down for about 6 months…:frowning:

#13

Warren, your observation about local support is spot-on. One of the Perth retailers is checking with an outfit that has built some neat transformers and controllers for them in the past. It’s just a matter of scale; it looks like these folks have aimed their product line primarily at HO and N rather than G. I’m hopeful something will come of it.

I’ve also had a look at some of the transformers sold here to do garden lighting. One in particular takes 240v in, puts 12v DC out, is rated at 300 VA, and costs under $200 Australian. Doubt I’ll go that way, though - wouldn’t have a clue about how to attach train controllers to it.

Haven’t given up on an Aristo Elite or LGB Jumbo yet, either. The price on the latter out here is scary - and that’s without controllers.

#14
Dave Healy said:
Warren, your observation about local support is spot-on. One of the Perth retailers is checking with an outfit that has built some neat transformers and controllers for them in the past. It's just a matter of scale; it looks like these folks have aimed their product line primarily at HO and N rather than G. I'm hopeful something will come of it.

I’ve also had a look at some of the transformers sold here to do garden lighting. One in particular takes 240v in, puts 12v DC out, is rated at 300 VA, and costs under $200 Australian. Doubt I’ll go that way, though - wouldn’t have a clue about how to attach train controllers to it.

Haven’t given up on an Aristo Elite or LGB Jumbo yet, either. The price on the latter out here is scary - and that’s without controllers.


Dave,

That local source should be the answer, we build that kind of stuff for the smaller scales, too. It is more or less a matter of scaling up the current capacity - the control elements stay the same.

LGB’s Jumbo has a “rare elephant” price ( would that be a white elephant?) when you look at what it is and what it does. But that’s just LGB’s way. :wink: :slight_smile:

BTW depending on what you run 12VDC is not quite enough. 18-20VDC is more like it, some mfgs want you to supply 24VDC. It all depends on the engines - how many boards are used as voltage-gobblers and if you intend to run everything as if it’s the Japanese bullet train.

#15

Once you can provide a stable voltage around 18 volts, a reostat would work for speed control. Just make sure it can handle the amperage. You don’t really need expensive power supplies unless you are running expensive electronics. I’ve known people to use car batteries and a reostat to run their trains.

Personally I would not even think twice about the LGB Jumbo. I’ve used it and really don’t like the feel. It’s too expensive for what you get. Also note, on the Aristo power supplies (Ultima and Elite) there is no controller. All you get is DC voltage out. Aristo does sell a stand alone controller though.

#16

Purchased a Bridgewerks MAGNUM 220RM 20 Amp 2-Track Manual Controller from Robby at RLD Hobbies in Albion, Illinois. Couldn’t get anything built locally - very surprising! Even the 1000w transformer that will sit between the 240v socket and the 220RM is coming from Queensland, on the other side of the country.

In other sections of the forum there are many upbeat comments about Dave Sauerkeld, owner of Bridgewerks. I second them. The man answers Emails. Under Products, Accessories on the Bwerks site there’s mention of specialty buttons that allow a little person to make a train run under controlled conditions. That’s perfect for my grandsons, ages 4 and 2. Over several Emails, Dave provided all the information needed to buy the right type of switch locally and instructions on how to hook it up. Low-tech, sure, but a real boon to someone with my limited experience.

I went with RLD because Robby was the only bloke I could find who was prepared to accept payment by wire transfer, and because he also answers Emails. Since I am used to fee-free web transfers between my own accounts AND between my accounts and accounts at other financial institutions, it came as a surprise that free and easy transfers don’t seem to pertain in the Home of Free Enterprise. :slight_smile:

#17

Glad you got your power supply situation solved.

On the money thing, most everyone here in the USofA uses plastic to make purchases. Only actual banking transactions take place by electronic transfer. If I want to make a purchase that I’m outright paying for I just use a Debit Card. If I want to make a payment on my credit cards then I do an electronic funds transfer. The major reason for that is security. Purchases on my debit card are backed against fraud same as a credit card but if I give someone my bank account information I have no protection.

#18

My situation is different, because I have both US and Australian citizenship and bank accounts. I wanted to pay for the equipment with American dollars from my US bank account, even though I live in Oz.

With wire, I don’t give the retailer my bank data; he gives me his. The retailer retains the goods until the bank notifies him that payment has been received. Only then does the retailer part with his property. If the bank gets it wrong, the bank wears the responsibility. That means the bank is careful. If there is a safer way for an average Joe to shift money, I haven’t heard about it. Plastic scams, on the other hand, are legion.

If I use an Aussie credit card to purchase goods in US dollars, I get soaked an additional percentage on the currency conversion since I ultimately have to pay for the goods in Aussie dollars. I wear this if I have to, but I like it better if I don’t have to.

Since 1996, I’ve spent roughly equal time working in Oz and in the States. I’m no expert on the health insurance, taxation, frequent flyer, credit card and other financial issues this raises, but I know a few of the gotchas.