Third-party images may be clicked on for source citations. DCC Circuit Breakers Circuits breakers are resettable devices that interrupt power when a short-circuit occurs. Some require a manual reset e. For DC, this kind of protection normally used a simple heat-based device similar to the circuit breakers used in house wiring. Model railroads are very prone to short circuits.
Capacitors need to charge when power is first applied to Free erotic cartoon stories track. The lamp has a very low resistence, so it doesn't drop Model train circuit breakers of the Model train circuit breakers, and the train runs normally. I received my new PS-X 4-circuit circuit breaker yesterday and installed it today in place of my existing 3-circuit circuit breaker. You can also program the PSX-1 to be used as an occupancy detector, using either track current or a photocell Mpdel detect the presence of a train. They did not mix well with the Lenz system we were using at the time and were an even bigger headache with the inrush current of sound locomotives mostly Tsunamis. Value 1 star 2 stars 3 stars 4 stars 5 stars. I do have a PSX1 because I plan on having additonal power districts.
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Also on this page are calculators that will give the output times of LM timers for a given set of component values. The circuits on this site are purposely designed to be as simple and efficient as possible. Needless to say, I have placed an external inline fuse on the output. It might be coincidence, but this is the third meltdown I've had and all have happened about the same location of the layout, right before the entrance to the reverse loop where both rails are gapped. If set up the second way - that's why the short in one section kills the whole layout. They even have a "weak booster" mode to ease the load onto Digitrax boosters to keep them from shutting down with several sound locos in the same district. The outputs have settable delayed release and can source or sink up to milliamps. My Bran mash feeding older horses has a amp service with a fairly good sized main panel. Aug 9, 6. The lamps normally used in these fixtures either Model train circuit breakers out or often would became loose and would go out.
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- Reviewed in the August issue by David Popp, senior editor.
- So cheap you can install one on every turnout and the give a local visual indication of where the problem is.
- The "Mission" of this site is to provide some useful information about electronics and electronic circuits to model railroaders and others in general.
- In the DC days, I thought I was pretty astute about the electronics involved but I'm finding out, often the hard way, that DCC is a whole new ballgame.
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Third-party images may be clicked on for source citations. DCC Circuit Breakers Circuits breakers are resettable devices that interrupt power when a short-circuit occurs. Some require a manual reset e.
For DC, this kind of protection normally used a simple heat-based device similar to the circuit breakers used in house wiring. Model railroads are very prone to short circuits. Running into a track switch set against the train will usually cause a short. Cars with out-of-gauge wheels can cause a short when running through a switch normally.
DCC is also a form of alternating current, and that coupled with the high current can produce an electric arc between conductors that are close but not quite touching, which gets hot enough to melt metal and weld cars to track. Every DCC command station or booster contains a built-in circuit breaker, but there are situations where you need to add additional ones between the power supply command station or booster and the track.
This page discusses DCC circuit breakers and their operation, as well as providing some suggestions on where and why you might want to have additional ones. More flexibility likely has a higher cost per circuit breaker. So if you plan dual-mode operation, keep that in mind. Note: while some of the operational advice below comes from my own experience, a lot of it has been culled from numerous manufacturer documents and helpful posts across the web.
Circuit Breaker Operation Make sure you test each section of track once it is built to ensure that the circuit breaker works reliably. There are two critical tests: 1. Remove it, and it should reset. As usual, Wiring for DCC is the place to go for guidance on that. Now put your most power-hungry train on the same section of track. Then apply the quarter test. Note: when performing the quarter test, keep your fingers away from where the quarter touches the rail. If you get an arc there, you could get burned.
Technology Most modern DCC circuit breakers are solid-state devices i. These allow more flexibility of configuration and control, but this does imply a higher cost.
Relay-based designs are also available, and can generally be recognized by having one large black rectangular box per circuit breaker see the Digitrax PM42 for an example. According to one post I saw, Lenz has apparently stated that their warranty is void if lightbulbs are used, as their built-in protection may not operate properly, so consult the manufacturer of your power supply before using light bulbs to determine if that is an issue for you.
With careful selection and an awareness of the risks, lightbulbs could be used and do offer a very low cost solution. Trip Current One key characteristic of a circuit breaker is the current at which it trips. This is often approximate, as normal variation in components makes this difficult to calibrate exactly. However, power supplies often provide more power than the rating, so a 5. As an example: PSX recommends using their lowest 1.
And for 5. So, if you know your largest train is going to need 1. Also, because measurements of peak load can themselves be approximate, you might want to add even more safety margin.
For example, if your choices were 2. This varies a lot, even within the same scale and larger scales will have larger current needs. Older motors may be less-efficient designs, bulb lighting can easily draw ten times the current of a small LED per light 60 milliamps versus less than 10 milliamps.
Failure to Trip A circuit breaker is only useful if it works when needed. Some design decisions can prevent this from happening. The two primary causes are excess normal resistance, and inadequate power current from the supply. A circuit breaker works by sensing high current during a short. High resistance in the track or wiring will reduce current.
For example, if the power supply is 3. Guideline 1: keep wiring between the circuit breaker and the track both as short as possible, and of a reasonably large gauge. If you want to use a 3. Now of course you can put the circuit breaker across the room.
But if you do, having large power bus wires to the layout rather than feeding the track in one place and using the rail to carry the power becomes even more important. Feeder size can also be an issue. Wiring for DCC has a nice discussion of how large feeders need to be based on the length of track they feed. Guideline 2: make any added circuit breakers significantly smaller than the power supply rating.
One amp less is probably a good rule of thumb. See the Circuit Breaker Sizing subsection below for additional detail. Unnecessary Trip or Reset Failure A circuit breaker that is too small can trip during normal operation. Some of the reasons for this were covered up above, but there are more. A train equipped with constant-lighting or a sound system will contain capacitors to store power. In some cases, the circuit breaker will not trip under normal conditions, but once it is tripped by a short, it will fail to reset actually it just keeps resetting and tripping due to the same problem.
Capacitors need to charge when power is first applied to the track. Left to themselves, capacitors look like a short-circuit for a very brief time, although a well-designed power system will have extra current limiting components to reduce the inrush current.
A DCC circuit breaker needs to wait a short time before reacting to a short circuit in order to not trip on a high but short-lived current. This is mainly controlled by making the circuit breaker larger.
So for that hypothetical 0. Circuit Breaker Placement Where do you put circuit breakers? Well, if you are the only operator, you could stick with just the one on your power supply. Although you could have others to make them work more reliably on a very large layout, and to improve protection. Circuit breakers provide two basic functions: 1 protection of the track, trains, and power supply from damage due to short, and 2 isolation of other trains from problems caused by one train.
The power supply circuit breaker will be rated at the level of the power supply e. This will work because the power supply is actually designed to put out even more power, to ensure its own breaker trips in a short. However, this means that any short will cause that much current to flow for a brief time.
This can cause more damage than a lower breaker setting, particularly if the breaker is slow to trip. And, as noted above, longer wiring can prevent, or delay, the breaker from detecting the short.
When working with very large power supplies e. This is more cost-effective than buying several boosters, but it is ultimately a compromise design. The protection will still cause disruption of multiple trains when it activates, and it will still allow fairly high currents through for a short time before activating, because each circuit breaker has to be sized for multiple trains.
This minimizes wiring-related problems and allows trip current to be as low as possible. That generally means either on a single feeder, or on a sub-bus providing power to a set of feeders, but not on the main DCC bus. So, where are they needed? A better approach is probably to put one on each mainline track every several blocks.
This way, if you have a double-track main, a short on one might affect trains ahead of or behind it, but not those on the parallel line.
And any train behind the one with the short is going to have to stop until the problem is fixed anyway. Guideline 2: place them on individual tracks lines , to minimize the impact of a trip by one train on separate tracks. Yards are a common place to have shorts lots of track switches , so a yard should be on a separate circuit breaker from the main. A very large yard, which would be worked simultaneously by several switchers, might benefit from multiple breakers e.
The exception would be a large industrial spur which might be worked by a local while another train was passing on the main. This is essentially the same as a small yard, and would benefit from its own protection.
Guideline 3: place them where there will be separately-operated trains. Example The following diagram shows a somewhat overbuilt layout power system.
More reasonably-sized layouts will omit various portions as redundant. However, the full diagram is useful for seeing all of the options. The above diagram shows a layout with multiple power districts, two shown, each subdivided into blocks, with each block having one or more track feeders.
The track feeders connect to block terminal strips. The block occupancy detectors can be placed as shown, to enable detecting trains approaching the end of a block, or they could be placed between the sub-bus and block feeder strips if all that is of interest is knowing if the block is occupied. The feeder terminal strips themselves connect to the district power bus, which is a track bus limited to that district. One set of circuit breakers is placed on these connections.
These breakers would be set to perhaps 1 or 2 Amps, to protect trains in one block from shorts caused by trains in another block. Each district bus is connected to a main bus, fed by a booster or command station , and a second layer of circuit breakers is used to connect the district busses to the main bus. These would be set to a higher level, adequate to handle all trains in the district, perhaps 4 or 5 Amps. If there was more than one booster in use, each would have its own Main Bus.
On a small layout, the feeder-strip breakers could be omitted, and the district breakers could be set to a smaller trip current. The benefit of the two layer approach is that a very high-current booster such as 10 Amps could be used, while limiting current in the district bus to 4 or 5 Amps, which allows lower-gauge wire to be used with electronics, without any fire risk in a short.
In open air, the difference between 5 and 10 Amps is the difference between a minimum wire size of 22 or 20 gauge, but if you want to ensure wire temperatures stay below 75C due to scenery materials or similar close to the wire , the choice becomes 20ga vs 16ga.
Almost immediately, I got a shutdown. Skip to the beginning of the images gallery. This page attempts to show the voltage waveforms associated with model railroad DCC systems as they would be seen with an oscilloscope. Thus, they can handle restarting close to 20 locos with sound decoders in a single district. Surely someone out there has a solution?
Model train circuit breakers. best DCC circuit breaker?
When you buy a multiple, you get a single board with two to four units on it. They are electronically independent but still connected together. They are scribed to snap apart, so you can easily cluster them or use them independently, as you choose. Every other system I know about falls between these extremes. They even have a "weak booster" mode to ease the load onto Digitrax boosters to keep them from shutting down with several sound locos in the same district.
It doesn't offer as many different versions and it has a few less features. It, too is "sound decoder aware". It is older technology and does not play well with sound decoders. I'd much rather have an EB1. Most personal layouts I've seen have two to six districts. Cook your spouse dinner at home one night and you'll save that much. Can't cook? Okay go for a couple of weeks of bag lunches, or stay away from Starbucks for awhile!
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Lucida Georgia Trebuchet Palatino. The circuit shown on this page allows inexpensive digital multimeters to measure currents in DCC systems. The circuit is designed to use a 20 milliamp DC milliammeter to monitor the current but other types of meters could also be used with this circuit.
This page features a circuit that has twenty open collector outputs that turn on one at a time in a continuous sequential manner. The circuits are designed to drive light emitting diodes or low current, low voltage incandescent lights but can also drive other loads of up to 80 milliamps.
The circuits have variable trip current settings and are designed for low current applications. Two circuit breaker designs are shown; The first has its power isolation device on the Low or common side of the circuit while the second has it isolation device on the High or supply side of the circuit. The circuits on this page are switch machine drivers that can be used to operate Stall-Motor type switch machine motors.
These supplies are reasonably inexpensive due to their age and have been removed from old personal computers. This block occupancy detection circuit uses a current sense transformer to isolate the detector circuit from the track power circuit. The output section of the circuit takes its power from an external power supply and uses a LM timer to provide the release time delay and both an Open Collector and Bipolar output each detector.
This page presents block occupancy detector designed for general purpose use on systems where the polarity of the power to the track is reversible.
This page is about a block occupancy detector that uses an optoisolator to electrically separate the track from the detector output. Four variations of the detector are shown. This page shows a less expensive alternative to screw type terminal blocks for use on printed circuit boards. These are described as "Push-In Terminals for 0. Holes" and require soldering of external connections. The replacement circuit uses discrete components and is essentially the same as the internal circuit of the LM This is an inexpensive way to make a stepped resistance box using a Single Pole - Twelve Position rotary switch and eleven resistors for each switch.
This pages in this section of the site will present basic information about electronics for Model Railroaders. Pages will be posted with information on various components and simple circuits that a model railroaders are likely to use in their hobby. The handle of switch can then be used to indicate the route selected. The circuits are also able to control LEDs that could be used to indicate the selected route.
The circuit is also able to control LEDs that could be used to indicate the selected route. This circuit is for a "F. The circuit is based on the LM timer chip. The circuit can also turn the signal OFF for approach lighting if desired. This page attempts to show the voltage waveforms associated with model railroad DCC systems as they would be seen with an oscilloscope. Also methods of measuring DCC system voltages and currents are shown. This page features H-Bridge circuits used for controlling direct current motors.
Several designs are shown using both CMOS and bipolar power devices. This page presents a new version of the - 'Modernized "Toy" Throttle' circuit that is shown on the 'Various Transistor Throttles' page at this site. This version was specifically design to be used by a handicapped person and is controlled by a single axis joy stick that operates microswitches at each end of its arc of travel. The calculators on this page can be used to find current limiting resistors and currents for Light Emitting Diodes.
The first calculator determines the resistance for a desired LED current while the second calculates the current for a given resistance. This page shows some methods of track routing control for Stall-Motor type switch machines. The principle method uses a 2 Pole - Multi Position rotary switch while an alternate uses optoisolators and transistors to select the routes. Some pictures of the tunnel boring machine used to dig the second railway tunnel under the St.
This page presents general information and tips for the LM timer. If you would like to try any of these ideas please take time to do some experimenting before using them in an actual circuit. All of the solutions on this page can be applied to the LM Dual timer chip as well. Also on this page are calculators that will give the output times of LM timers for a given set of component values.
This page presents a low tech, low cost and reasonably simple automatic reversing circuits. They uses toy train set power packs to control the top speed of the shuttle while diodes in the track circuit provide a method of stopping the shuttle at the ends of the track as well as crude control of the trains acceleration and deceleration. This page is for an automatic direction reversing circuit that will control the point to point operation of a "shuttle" such as an RDC car or a short train.
The shuttle will travel from one end of the track to the other wait for a preset time and then return to its start point, wait and then repeat the cycle. The circuits on this page are basic designs for "Diode Matrix" switch machine control systems that can be used to operate "Stall-Motor" switch machines in 'Ladder' type storage yards or other multiple turnout areas.
The driver circuits themselves use LM dual timer chips to reverse the polarity of the voltage to the switch machine motors. This train detector makes use of hand held laser pointer devices that are widely available to detect trains over long distances.
This page is about automatic reversing loop control circuits. The first switch machine controller is very basic. More complicated circuits will be added as they can be thought up and tested out. The "Automatic Station Stop Circuit" brings a train to a station stop in two braking steps and then sends the train on its way after a set period of time. The first braking step slows the train gradually until it is at the station. The second brake step then stops the train just quickly enough to allow the first or second coach to stop in front of the station.
This page features a simple, three IC unipolar stepper motor driver that can be used to drive relatively low speed applications at currents up to 1 ampere per phase. The circuit is made with parts that are available from a variety of sources. This page features a Bipolar stepper motor driver using three ICs. The circuit can be used to drive relatively low speed applications at currents up to 1. The circuit uses parts that are available from a variety of sources. This page features basic, visible light photodetector circuits that can be used to detect trains.
These methods would normally be used with the photo sensor mounted between the rails. This page presents various capacitor discharge power supply circuits for use with twin coil switch machine motors. Also shown are some optional wiring methods that can be used to enhance the availability and control of these supplies. The following diagram shows the pinouts for some of the integrated circuits and transistors used on these pages.
They are designed to drive Light Emitting Diodes but could be used to drive low current incandescent lamps. Here is a way to use old wire coat hangers to make simple and efficient wiring harness guides that can help keep your layout wiring neat and tangle free. This page features a photo and schematic from an article that was published in the August issue of Model Railroader Magazine.
The article was titled "Build a model railroad odometer car". The Crossing Diamond Protection circuit is designed to prevent collisions where one rail line crosses another.
Using phototransistor sensors to detect a train the circuit will disconnect the track power from the line that crosses the occupied line. The circuits presented here will prevent turnouts from being thrown while a train is on the switch, ideal where the switch cannot be seen by the operator. They use phototransistor sensors to detect the train and have a short time delay to compensate for gaps between cars.
The circuit can also be used to protect crossovers and ladder tracks with the addition of more sensors. This is a circuit that will give an audible warning that a train is entering a particular section of track.
The detector also has a LED that indicates when a train is entering or leaving the block. The drawings and photos below are for an operating incline railway that was built by the London Model Railroad Group for its 'O' scale model railway club located at London, Ontario, Canada.
This is a single car model loosely based on a double car incline that operated at Port Stanley, Ontario. This page will show a number of variations on DC, transistor type throttles.
The throttles range from 'tried and true' types to 'experimental' designs. The following is a schematic drawing of a Silicon Controlled Rectifier type throttle for use on larger scale model railroads. Three versions of this throttle are shown on this page. They are not sophisticated designs but work well and are tough and reliable. The following are examples of home made solid state relays that could be used to replace mechanical types in many model railroad circuits.
The 5 Times Around circuit was designed to automatically let an N Scale locomotive and car travel around a loop 5 times and stop for approximately a minute and then repeat the cycle. This page will provide some basic information about voltage comparator integrated circuits and and to act as reference material for other circuits.
The Circuit is for a 'Shunt' type ammeter that allows a meter movement with a small current rating to be used to measure a much larger current.
Hornby Forum - Circuit Breakers
We have searched the web to help you find quick design ideas. We make every effort to link to original material posted by the designer. Please let us if you would like us to link to or post your design. The circuits have variable trip current settings and are designed for low current applications. Two circuit breaker designs are shown; The first has its power isolation device on the Low or common side of the circuit while the second has it isolation device on the High or supply side of the circuit.
The circuit breaker's trip current setting has an adjustable range of 0. Custom Search. Schematics Index. Hobby Corner. Dave's Circuits. Electronic Resources. Contact Info.
Imagineering Ezine. Discover Solar Energy. Faraday Touch Switches. The digital voltmeter is set to its lowest range and indicates the resistance in the track circuit by measuring the voltage drop in a given section of track The throttles range from 'tried and true' types to 'experimental' designs.
There can be minor differences between timer IC's from different manufacturers but they all should be useable for any circuit. Scroll to find this design The circuit is based on the LM timer chip. As can be seen it is a modification of the basic transistor throttle shown above. All of the detectors in this test functioned correctly with no evidence of interference between units.
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