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DCC help Bridgewerks and Digitrax

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MikeMcL

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Discussion starter · #1 ·
Hello All,

I've been lurking a few months and just joined up. Sorry my first post is a plea for help!

Background: I've been model railroading on and off all my life, just started my second garden railroad after a 7 year absence. I had digital control before DCC was standardized using Keller Engineering system with HO scale, now obsolete. I've had Digitrax in my last garden RR in the early 2000s with Bridgewerks Mag-15 power supply, and had over-temp shutdown problems with the old garden railroad.

So I started this new garden railroad Feb 9th. I have an 8amp DCS200 command station being powered by the Bridgewerks Mag-15. After about 10-15 minutes of running two trains, the thing shuts down and you can't touch the heatsink. If I wait a couple minutes I can get them going again, but they will shut down in much less time after the first shutdown.

I used an ammeter between the power supply (Bridgewerks Mag 15 at 24v DC) and DCS200. These are the readings:

Power on just the dcs200: 0.24 amp

Aristo FA w/sound and 3 lighted streamliners: 2.4 Peak uphill, 1.3 lowest downhill, mostly hovered in the
 
#2 ·
Hi Mike,

Is it the heatsink on the Digitrax unit that is getting hot or on the Bridgewerks? I'm assuming it's the Digitrax unit, and I would suspect the Bridgewerks unit is putting out too much voltage for it. Can you throttle back the Mag-15 or is it fixed output? I would throttle it back to say 3/4 of max and see what happens. Those Bridgewerks units are famous for putting out more voltage than they are supposed to so that's where I'd start.

Keith
 
Discussion starter · #3 ·
Hi Keith,

The heatsink on the Digitrax DCS200. You're right, I suspect the Bridgewerks puts out too much voltage. There are multiple fixed outputs. 24 VDC; 12 VDC; 24 VAC. The trains won't run using the 12VDC tap, barely moving. I think I blew up the DCS200 using the 24VAC tap. It just came back from Digitrax repair, so I'm trying to use the 24VDC. I believe it is putting out even more than 24V, I put a multimeter on it a while ago and I don't remember the reading, but it was in the upper 20s without a load.
 
#4 ·
Hi Mike,

Yes I'm afraid you will have to figure out a way to drop the output voltage on the Mag15 if you want to keep using it. I'm not sure what the DCS200 is able to take but I suspect you will be better off selling it and getting yourself something like a Meanwell power supply that is better regulated. Greg might be able to advise how to drop the voltage on the Mag15 if it is possible.

Keith
 
#8 ·
Mike
I think the Bridgewerks should be regulated to 24v. If it puts out more than that, I think it is defective.
I don't know much about Bridgewerks supplies except they are expensive. They have nice packaging,
but that is alot of money for the capabilities. I use Meanwell. You could buy a well regulated Meanwell
24V/240watts for less than $75. If the Bridgewerks puts out more than 24V, I would call them. You should
be able to make it work. If it does put out 24V, maybe there is a problem with the Digitrax.
Hopefully, the Digitrax input is well protected.
Tom
 
#9 ·
From what I've read here is Bridgewerks are great for analog track power, but run into problems when cranked up on full power for DCC. They are know to put ou more power than specified. On track/ analog one would think great! more pulling power, but on digital at near peak input any extra can be bad... as the OP has seen.
Sell it and get a meanwell type regulated power supply. I picked up a close out brand for my work bench power supply for about $ 40. I searched for discout and accepted a closeout brand. The only thing is you need to add the power cord, local hardware stores carry those.

John
 
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#10 ·
The Bridgewerks units are great for running trains in traditional "analog" railroads, but their VDC outputs are notoriously high without any kind of load on them. I've measured upwards of 30+ volts on a few. I'd echo what has been said already--sell the Bridgewerks and buy a Meanwell or similar. (And have enough cash left over for a decoder or two to boot!)

Many folks gravitate towards 24 volts for their power supplies, but keep in mind that there are decoders out on the market that don't particularly like voltages too far north of 20 volts, despite what the "standards" say they should be able to handle. While most of these tend to be decoders intended for smaller scales, (a) those decoders do find their ways into LS locomotives on occasion, and (b) there are the occasional "Large Scale" decoders that likewise freak out at voltages north of 20 volts.

Frankly, unless you're going to be running trains at "mainline" speeds, you're probably not going to need 24 volts. If you're running narrow gauge, you're probably not going to need more than 18, as their speeds were far lower than their standardard-gauge counterparts. If you know you're going to have a fair amount of control with regard to the locomotives and decoders run on your railroad, then you can tailor your choices to those which can handle whatever voltage level you choose. If you foresee yourself holding operating sessions where others bring their locomotives to run, you may want to consider using a slightly lower voltage that's a bit more universally friendly to most decoders. I know I'd be reluctant to bring another loco to an ops session if my first one went "poof" the first time around because of the track voltage.

Later,

K
 
#11 ·
Newer decoders for HO and Large scale from Zimo now have much higher ratings. I use their HO sound decoder on small engines and the rating is 50 volts.

Also watch for current ratings on all decoders, many have a peak rating and a motor rating, and the total current of lights and motors are the motor rating, in other words if you have smoke and lights consuming 1 amp, then the motor rating is really 1 amp lower.

Also, older decoders seem to have less efficient mosfets, thus higher heat outputs, use these in single motor engines.

For my LGB handcar I use the Zimo non sound MX621 and it fits in the barrel with room to spare. This decoder has a .8 amp rating.
 
Discussion starter · #12 ·
Thanks guys, I was afraid I would need to get a new power supply. Now it's confirmed!

I think the Bridgewerks voltage is way above 24VDC, I'm not home to measure right now, but it may have been 30+

Is there a Meanwell model number you would recommend?
 
#14 ·
Hi guys, I am new to DCC and also have a Bridgewerks Mag 15 supply that I would like to use with it. I discovered a solution that will solve the problem with the
high output voltages with these supplies. Simply, if your supply has the "yellow" remote throttle terminals on the rear you can control the total output voltage.
Run the Bridgewerks Throttle up fully. Then experiment with a variable resistor (about 25K ohms across the terminals) until you get the voltage you want.
I found a sweet spot about 13K ohms for 22 volts. Once you have the total voltage you want I would replace it with fixed resistor. This fix does not work with the fixed output DC.
Enjoy!
 
#15 ·
that still does not work as well as a regulated supply... the bridgewerks is not a regulated supply, and the owner does not recommend it for DCC.

If you have one already, then the "trick" above will work, but you still won't have the consistent performance of a real regulated supply. If you were not using it for anything else, I'd sell it and buy a supply and a couple of locos from the proceeds.

Greg
 
Discussion starter · #16 ·
Yeah my bridgewerks mag 15 is not a throttle, just has 12vDC, 24vDC, and 24vAC taps. They meter way higher voltage than what they are labeled. I'm convinced this power supply is my problem. I cancelled the order for the $23 power supply because it wouldn't ship before we relocated north for the summer. I miss my garden railroad already, returning to Florida in September. But I did successfully use an MRC power pack that was rated 60va @ 18vAC accessories terminal (3.3 amp). Ran both trains for about 4 hours and the heatsink of the DCS200 was barely warm. I will definitely get the 15amp power supply from Amazon for $23 when I return.

mag 15

My barren railroad as it looked when we pulled out of the Florida driveway to spend 4 months in PA. Exactly 3 months from the start of construction to the day. Structures and trestle were stored in the shed for the summer.

Image
 
#17 ·
Be careful of VA ratings... the 60 VA does not necessarily mean at max voltage! VA is very deceptive on model train power packs.

Legally, it only means that at SOME voltage or current, the product of voltage times current is 60.

I had a 60 VA MRC unit that would put out 24 volts, but it would not do 60 VA at 24 volts... it could not achieve that high a voltage under heavy load.

Greg
 
Discussion starter · #18 ·
Thanks Greg, the MRC power pack at 18vAC 60va was a temporary measure for running the two trains during a going-away party. It held it's own for about 4 hours running two DCC trains. When I used an ammeter, I was only peaking at 3.5 amp for a second when the lighted streamline passenger train (F unit) was going uphill every 3.5 minutes, mostly the current was below 3 amp with the two trains running. That was measured with the bridgewerks ~30 volt, so I hoped that the MRC could handle the current at 18v. I will get the 24v 15a power supply in my amazon link above when I return in September.
 
#19 ·
I'll bet the trains ran pretty slow at 18V! Basically you were probably getting 15-16 volts to the motors.

No real negative implied, but some locos are geared so low that they might only go 45 mph at that voltage.

Your measurements with the Bridgewerks at about 30 volts, was that DC to the rails or as input to the DCC system? Most DCC systems would have trouble handling that
 
Discussion starter · #20 ·
Yeah, the trains ran a little slow at 18v from the MRC power pack, but was able to attain an acceptable speed.

The ammeter readings were between the bridgewerks and Digitrax input. I didn't try to measure the current from the Digitrax to the track. I read somewhere that it is tricky to read a correct value from the digital signal.

The Bridgewerks was definitely too much for the Digitrax, kicking the thermal overload shutoff after 10-15 minutes. You couldn't touch the Digitrax heat sink when powered by the Bridgewerks.
 
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MikeMcL
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