# Bridgeworks power supply questions



## Michael L (Mar 18, 2014)

Silly question but here goes. I've been looking at BridgeWorks power supplies and noticed that there are models in the 20-25 amp range. Do you need a 20-30 amp curcuit breaker installed for one of these? Wouldn't it pop a normal 15 amp household breaker under load? However, I can't imagine ever having a 25 amp load on my track. Just wondering...
Mike


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## BigRedOne (Dec 13, 2012)

Electrical power is measured in Watts. Watts are volts multiplied by amps. Thus, a 24 volt, 20 amp power supply is producing 480 Watts.

Your household circuit is 120 volts, thus it will deliver 480 Watts at only 4 amps (not accounting for losses in converting AC to DC or stepping down the voltage.)

So, well within the capacity of a normal household circuit.


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## Michael L (Mar 18, 2014)

Thanks so much - that makes sense. AMp rating is on the dc side of things. Learn something new everyday. How are the bridgeworks? any experience?


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## Treeman (Jan 6, 2008)

Bridgewerks are considered a rugged well made power supply, made in the USA with a five year warranty. One draw back is that they are unregulated, not good for DCC.


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## chuck n (Jan 2, 2008)

I have two BW power supplies. One is 10 amp and the other is 15 amp. I am very pleased with them. I like the LED voltage and amp indicators, it is nice to see what is happening. The 10 amp unit has a built in remote. A key fob controls the speed and direction. The 15 amp unit has a separate remote unit (UR-15). It also works from a remote key fob. I have two of the UR15s. One is kept with the 15 amp unit and I have the other on my home made power supply at a separate location.

I have been pleased with them. As was said earlier they are made in the USA. THAT MEANS A LOT TO ME.

Chuck

PS. I use DC on my tracks.


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## Dan Pierce (Jan 2, 2008)

So, most would think that a 4 amp fuse/breaker would be ok for 480 watt rated supply, BUT the initial surge current when these are turned on is much higher than 480 watts divided by 120 volts giving 4 amps. Capacitors can draw a lot of current when the initial charge occurs. DCC users have the same capacitor issues when first turning on a layout with large capacitors inside the cars/engines (read anti flickering lights)
The input can see more than 4 amps and I would use 6 amps for the input protection.


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## docwatsonva (Jan 2, 2008)

I have one BW 15A supply driving 2 of their remote control units, one for an outside loop and the other for an inside loop. I have run 6 engines at the same time off the one 15A supply with no problems.

Doc


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## chuck n (Jan 2, 2008)

For my purposes, 15 amp PS is sufficient. You need to decide the maximum power you will need on the track at one time.

How many engines? I figure 1 amp per motor. For some engines that may a little high.

Are you planning on using any smoke units? They require extra juice. How much, I don't know because I either turn them off or cut one of the wires.

Are you going to run lighted passenger cars from track power? My USAt streamliners when lighted require 0.5 amps per car.

If I pull 8 USAt streamliners (4amps) with a USAt ABA F3 set (6amps), that is a 10 amp train.

Freight trains don't have lights, except for the caboose, so they will require less power. Just that needed for the engines.

Chuck

Grades and curves will also require more power. The steeper the grades and tighter the curves, the more electrons needed to turn the motors.


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## noelw (Jan 2, 2008)

Treeman said:


> Bridgewerks are considered a rugged well made power supply, made in the USA with a five year warranty. One draw back is that they are unregulated, not good for DCC.


Like mike said. and also, don't try to use them with a Aristo R/C TM. unit.. It will blow or shut them down due to no load to reg. the over voltage it can put out .. My BW 15 amp showed 34 volts with no load.
We also had here for a while a BW older Four throttle unit and it did the same thing.

If you use a few LED.s in pass cars and using a Resis. with them, and no other loads such as a motor or etc. Just using the track voltage, BW can't see the small load and it will most likely blow them.
We do a lot of testing & installing LED's for guys and found out by putting two or three small Auto 12v. lamp in series across the throttle variable D/C output it will be around now 24V's and will works fine. It see's a small load with very little amp draw.
Not sure on DCC due to we don't use any here.

Our BW has digital voltage read out and not sure if the older BW with old voltmeter that has a small coil in them will have enough load to regulate or see a small load.

Other than that, BW is a darn good power unit and will last a long long time.


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## du-bousquetaire (Feb 14, 2011)

Right mine got blown out by a thunderstorm a $500 unit plus shipping to France gone just because there was lightning in the neibourhood. What that means is: No protecrtion on the output! Super made in the USA.


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## Greg Elmassian (Jan 3, 2008)

It's a design that has not changed in many years, and almost exclusively used indoors. Sorry to hear it was blown up.

Was this outside and still connected to the rails?

Greg


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## du-bousquetaire (Feb 14, 2011)

No it was inside but connected to the rails (a problem I have now solved with plugs to insulate the outdoors from the power supply I also slide the rail joiners off).








What happened is that during a thunderstorm lightning hit very close to the layout (It did not hit the layout) and enough high voltage was probably put locally in the ground, as the track is two tracks each 90 meters in circumference it picked up a good deal of those volts. It blew the revolution train engeneer receiver and the bridgewerks 15 amps transformer used as power supply. My neighbour during the same storm had the unit which switches from solar electricity to off line electricity which got blown too, so I ampretty sure its due to lightning .The circuit breaker is like welded, you cant activate it! I know a friend in Paris who should be able to repair it though. The price has gone up from 2013 from $406 to $525 plus shipping! This is a photo of the slot in the wall between the layout and the indoor terminus the French yard is on the left the US yard is on the right.


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## Dan Pierce (Jan 2, 2008)

Talking about lightning is very interesting to me. I see a cloud in the sky will discharge an electrical spike (lightning) and it will 'arc' to the ground traveling hundereds of feet. Then people thing using a on-off switch with less than 1/4 inch space will protect them. One person thought removing a 3 foot piece of track should protect them. I saw the lightning damage at a friends house where the lightning hit his shed 75 feet from his house. It traveled along the metal roof edge, jumped to the ground and built a 30 foot trough to his swimming pool motor which did have a #8 ground wire. So, I have seen first hand where there was no metal and the lightning traveled 75 feet toward a ground point.


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## du-bousquetaire (Feb 14, 2011)

Wow those are pretty wild examples of thunder damage. In my case the thunder didn't hit the pike at all, thank god. But it can be pretty frightening when it does I guess. Lets hope it doesn't. I have a three foot bridge near where that entrance to the indoor terminus is, I think that from now on when thunder showers are announced I will remove it. Right now I disconnect the track which still has rails within an inch of each other... Our high electronic world is so vulnerable.


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## Greg Elmassian (Jan 3, 2008)

Why not put a big ground rod near the entrance so the lightning will stop there? A nice 1/2" diameter copper rod in hydroscopic earth about 9 feet in the ground will work.

We had to have a similar ground for our RF testing at a place I worked... more to get a true ground to help measurements, and to ground our faraday cage.

Greg


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## du-bousquetaire (Feb 14, 2011)

Thatd a good idea. Thanks, Simon


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