Aword used for circuits in which one device operates the next in sequence. An electrical control device for opening and closing circuits.

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1 INTRODUCTION Various methods of controlling electrically operated switch machines are covered in this group of sheets. Included in the first are basic circuits and in the others Sheet #: Updated by: Updated: First Issued: Originally Compiled by: Page: D7j.2 George Sevier, MMR October 1999 October 1961 (D7c.551) John A. Dorsam and John P.Seehaver 1of 11 the applications of these circuits. All circuits have been selected on the basis of proven practicality., Low cost, flexibility and relative simplicity. Consult Data Sheet D7j as to mechanical features and general characteristics of the switch machines discussed in this sheet. DEFINITIONS CASCADE: Aword used for circuits in which one device operates the next in sequence. SWITCH: An electrical control device for opening and closing circuits. : Any motor, coil device, relay (or rotary relay) used to move the points of a turnout. For these sheets, divided into the following classes: STALL MOTOR MACHINE: TWIN COIL MACHINE: One having arotating armature and re quiring continuous current flow through the motor coil to hold it in the operated position. One having two opposed coils or solenoids, designed to be operated by momentary current flow. (Most twin-coil machines are likely to overheat or burn out if subjected to more than a momentary current.) TURNOUT: The trackwork element which separates one set of rails into two or more tracks. See Data Sheet D3c and Recommended Practices RP12. NPOSITION: RPOSITION: (Normal Position) -of turnout: position of switch points as assigned by the track plan designer; usually the main or most used route. -of switch: position which operates th eturnout to the Nposition. -of switch machine: position in which coil of relay, either type, is de-energized. In atwin-coil machine, position which holds turnout in N position. (Reverse position, operated position) -of all devices mentioned: Opposite of Nposition.

2 Sheet #: D7k Page: 2of 11 SYMBOLS NMRA graphical circuit symbols (RP ) are used with these additions: N R Twin-coil switch machine. When not essential to the circuit, cut-off contacts will not be represented in diagrams. M Motor switch machine. This machine has arotating armature that changes the position of the track switch from normal to reverse. The motor has astall feature. SM Any switch machine. DR Detection. POWER SUPPLYAND WIRING Twin-coil machines are generally operated by AC, although DC may be used. A4amp transformer of 18 VAC will operate at least two twin-coil machines simultaneously. It is imperative that push button switches are used for this application for instantaneous activation. Continuous power to twin-coil machines will result in non-operational burned out machines. Motorized Switch Machines require DC power supply of 1amps at 12 volts. These motors are designed to have power applied to them and not turned off. This is called the stall feature. Some motorized switch machines feature auxiliary co ntacts. Amicro switch can be used for the auxiliary contact. It is placed in the path of the throw bar or wire and is tripped as the machine changes position. No. 18 wire is adequate for most switch machine control needs. Smaller, more flexible wire is permissible within control panels. No. 14 wire, properly fused, is suggested for power supply to the panel. Refer to Sheet D7p for discussion of the common power return system, which has important bearings on this phase of layout wiring.

3 Sheet #: D7k Page: 3of 11 SWITCHES In general, twin-coil machines require momentary-contact controls. With proper circuitry,however, control devices are interchangeable for these machines. Refer to circuit diagrams in sheet D7l. All momentary-contact devices are shown in the diagrams as push buttons, but their electrical equivalents, such as spring-return toggles, may be used. Locking-contact devices include toggle switches, keys, rotary selectors and push-button selectors. The latter are useful because they fit well into some track diagram boards, but it may be difficult to obtain the correct number of butto ns and proper circuitry. Motorized switch machines can be controlled with adouble pole double throw toggle switch with center off or no center off. Leaving the switch in the on position will not burn out amotorized switch machine. BASIC CIRCUITS Figure 1shows the wiring of atwin coil switch machine utilizing two push button normally open switches. The coils will not heat or burn up because the power to the coils is momentary when either of the push button switches is depressed or closed. - N R + Figure 1 Figure 2shows the wiring of a twin coil switch machine utilizing asingle pole double throw switch without aspring return. This is where the auxiliary contacts on the side of the switch machine are used. If the contact arrangement is not used, the coils will heat and burn out. Be sure to note how the auxiliary contacts are connected (the closed contact is always opposite the position of the single pole double throw switch). Figure 2

4 Sheet #: D7k Page: 4of 11 MOTORIZED S There are two basic wiring diagrams for this type of switch machine. Figures 3and 4show the two wiring methods. Figure Figure 3 3 Figure 3uses adpdt toggle switch and aresistor to complete the circuit. The DPDT toggle switch is wired in the same manner that adirectional control switch would be wired. Note the two crossed wires that go to the four outside terminals. Figure Figure 4 4 Figure 4uses asplit power supply (or two power supplies wired in series )system with acommon return. The split system is more economical and takes less wiring than the wiring displayed in figure 3. An SPDT toggle switch is used in this circuit instead of the DPDT toggle switch.

5 Sheet #: D7k Page: 5of 11 MOTORIZED S -continued It is important to size the power supply correctly. The instruction sheet, that comes with the switch machines, suggests the correct power supply. If adifferent voltage power supply is used, the resistor or resistors will have to be resized. Figure 5shows how auxiliary wiring or indication is accomplished with the motorized switch machine. Today most model railroaders use the Light Emitting Diodes or LEDs. Some still use lamps. Both methods are shown in this wiring diagram. By adding lights using this method,it will limit the number of switch machines that can be put on apower supply. Toavoid this situation it would be wise to use amicro switch or switches for auxiliary contacts that would run the circuits for lamp or other track control. INDICATIONS The simplest indication system is the positioning of control devices on atrack diagram tha thas been drawn on the control panel. These switches should be located in such away that they indicate the direction that the turnout has been thrown. Amulti-contact selector switch or rotary switch with atwo position throw does an excellent job of handling indications. On all but the smallest layout it is important to have indicator lights for each turnout. This is especially true if a turnout is controlled from more than one location. Large layouts utilize many of these same techniques. Twin coil machines come with anumber of contacts mounted on the side of the machine. These contacts are u tilized for indicator lights,frog power wiring, or other wiring requirements. Light omitting diodes make excellent indicators. They come in avariety of sizes and shapes to fit your control panel. There are many different configurations for wiring switch machines and their controls. These depend on the situation on the layout, the desire to have the operation as true to life as possible yet simple to operate. Finally, the wiring is easy to maintain and trouble shoot. These data sheets are not intended to provide the model railroader with all the technical wiring and circuitry that might be wanted. Shown on the following pages are basic circuits and diagrams. These can be expanded and combined to address aparticular layout design or situation.

6 Sheet #: D7k Page: 6of 11 OF LADDER TRACK SWITCHES There are several circuits that will operate aladder track switch system. The trick to these systems are to figure out all of the configurations for the switch machines that are involved. This can get quite complex depending on the model railroader and the ladder system. The ladder yard or system can be wired with individual switch machine controls. This is great except that every machine must be thrown correctly in order to get the train to its destination. With the use of these ladder diagrams it is possible to push one button or throw one switch and the route you want the train to take is done in o ne or two throws of toggle switches or push button switches. Figure 6 Figure 6shows asimple ladder yard. Note there are seven different routes the train can take. These are listed as Athrough G. As was mentioned previously one can wire each machine separately which results in atotal of 6toggle switches to control 6machines. Take alook at Figure 7. This diagram shows how to wire twin coil machines so that when adesired button is pressed it operates all the necessary switch machines. Note that all push buttons except for Aand Ghave one normally closed set of contacts and two normally open sets of contacts. A person should shop around to obtain these switches. The w iring is straight forward. Follow one wire at atime when hooking up this circuit. Note the normal and return positions of each of these switch machines. This is important to get these right for the correct track designation. Figure 7

7 Sheet #: D7k Page: 1of 7of 4 11 OF LADDER TRACK SWITCHES -continued Route Individual coils 1N 1R 2N 2R 3N 3R 4N 4R 5N 5R 6N 6R Total coils thrown A B C D E F Diagonal lines show the energized switch machine coils for each row. 4 Figure 8 Figure 8is adiagram of what is called adiode matrix. This wiring is much simpler than the circuit in Figure 7and does the same thing. The matrix can be done on aplain piece of paper or if you prefer asheet of graph paper. Across the top of the paper each line represents the normal or reverse coil of atwin coil switch machine. Along the left side of the matrix are the various routes through the ladder yard or system. Diagonal lines designate the energized switch machine coils for each row. In the sample on the next page (Figure 9) we will have two switch machines and three tracks. Row Ahas one diagonal line going to coil 1N. Row Bhas two diagonal lines, one to coil 1R and the other to coil 2R. Row Chas two diagonal lines, one to coil 1R and one to coil 2N. The trick to this circuit is that adiode must be inserted in every switch machine coil that contains two or more diagonal lines. In this sample two diodes are required. These two diodes are both in the wire that leads to coil 1R. If we want the train to travel on route Acoil 1N must be thrown. If we want the train to travel route B, coils 1R and 2R must be thrown. Totravel route C, coils 1R and 2N must be thrown etc. As more tracks are added the matrix becomes larger and more diodes are required. The neat thing about this circuit is only three push buttons are required and two diodes.

8 Sheet #: D7k Page: 1of 8of 4 11 OF LADDER TRACK SWITCHES -continued 1N 1R 2N 2R A B C A B C A B C 1N 1R 2N 2R Figure 9 Figure 10 Figure 10 is another way of wiring aladder yard or ladder system. This is done using 4pole multi wafer rotary switches. The rotary switch or switches are rotated to the desired track and then a push button switch is activated to set up the desired route. Make sure to purchase the correct rotary switch or switches. Use the non-shorting type.

9 Sheet #: D7k Page: 1of 9of 4 11 INDICATOR CIRCUITS Figure 11 Figure 12 Figure 13 Figure 11is suitable for any type switch machine equipped with contacts or micro switches. Any power source compatible with the lamp or LED rating may be used because it is not part of the switch machine operating circuit. If anormally dark circuit is preferred, use only the upper portion of the circuit. Figure 12 utilized one contact to operate one indicator light. In the normal position the lamp or LED would be dark. In the reverse position the lamp or LED would be lit. Figure 13 is asimple wiring circuit using one LED. Remember that aresistor must be placed in series with the LED to keep it from bu rning out. The resistor is sized according to the voltage output of the power supply. If switch machine indication is desired from multiple locations the lamps or LED are wired in parallel. This will allow all locations to be lit. TURNOUT POLARITY CIRCUITS Figure 14 Figure 15 The purpose of circuits depicted in Figures 14 and 15 is what is called apower frog. These circuits insure that there is always power to the track in the direction that the turnout is thrown. In some cases the turnout relies on the spring tension of the point rails against the stock rails to complete the electrical circuit. This is not reliable when the points and the stock rails get dirty. They can cause some real maintenance headaches. These two circuits eliminate this. Polarity must be correct with the way the turnout is thrown or ashort circuit will result. Fig. 15 is similar to Fig. 14 but with a nadditional feature that eliminates possible short circuits between long thin points and stock rails by metal wheels, since the open point rail is of the same polarity as the nearby stock rail. Note the four insulated joints isolating the frog and the jumpers from the points to the stock rails.

10 Sheet #: D7k Page: 1of 10 of4 11 TURNOUT POLARITY CIRCUITS -continued Figure 16 Figure 17 Fig. 16 shows acircuit that combines the advantages of Fig. 15 with completely short-free stopping section, but at the expense of two sets of contacts rather than the single set required with either Fig. 14 or Fig 15. Fig. 17 shows an unaltered Custom-Line or Snap-Track turnout with shortfree stopping sections. DETECTOR LOCKING CIRCUITS Detector locking is aterm used for circuitry which prevents the turnout from being thrown under a train. Some form of detection is required. There are many systems on the market that will serve the purpose. They are not covered in this Data Sheet. Your local hobby shop most likely will be able to assist you with these circuits. When atrain enters atrack section equipped with a detection unit or units, arelay operates to lock the switch machine control circuit as they then stand. The turnout may not be thrown until the train has cleared the detection section. Groups of turnouts can be locked out in this manner using one relay. It really depends on the track configuration. The figures below show some simple detection circuits from the point they connect into the switch machine circuit. The internal detection circuits are beyond the scope of these date sheets. It is import ant to spend some time thinking out your layout operation and train movement possibilities prior to incorporating these circuits into your layout. Figure 18

11 Sheet #: D7k Page: 1of 11of4 11 DETECTOR LOCKING CIRCUITS -continued Figure 18 is suitable with any twin coil switch machine controlled by momentary contact devices (push buttons). Remember not to connect any other power return wires ahead of the detection relay contact except for additional switch machines that will be locked out at the same time. Motorized switch machines detection circuits are pictured in Figures 20 and 21. These two circuits are very basic. Any more elaborate circuitry would be beyond the scope of these Data Sheets. These diagrams are straight forward using adouble throw switch. Just remember that the detection device relay contact mu st be placed ahead of the control switch for the switch machine. Figure 19 Figure 20