Turnout Motors

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Short Definition

A motor that is usually connected to a stationary decoder to control a turnout.

Turnout control in the world of DCC is a way to control turnouts (or turnout motors) through DCC commands. Typically, turnout motors need to be powered though a stationary decoder to be controlled by DCC. Various manufacturers have various solutions. There are also several motor types to make things even more complicated.

Contents 1 Motor Types 1.1 Slow Switch Machines 1.1.1 Advantages of slow switch machines: 1.1.2 Disadvantages: 1.1.3 Slow motion switch machines: 1.2 Snap Switch Machines 1.2.1 Advantages of snap switches: 1.2.2 Disadvantages of snap switches: 1.2.3 Brands of snap switch machines: 1.2.3.1 ATLAS 1.2.3.2 KATO 1.2.3.2.1 N-scale Kato Turnouts 1.2.3.2.2 Controlling the Turnout 1.2.3.2.3 (a) The Official way 1.2.3.2.4 (b) The Other way 1.2.3.2.5 INSIDE THE KATO TURNOUT CONTROL SWITCH #24-840 1.2.3.2.6 INSIDE THE KATO POWER ADAPTER #24-842 1.2.3.2.7 How a DPDT Reversing Switch Works 2 Stationary Decoders 2.1 Digitrax 2.2 Lenz 2.2.1 LS100 and LS110 2.2.2 LS150 2.3 NCE 3 Wiring Stationary Decoders 3.1 Using A Separate Booster

[edit] Motor Types

There are several motor types, but they fall into two basic categories:

• Slow motion - Such as the tortoise.
• Fast (or snap) Motors

[edit] Slow Switch Machines

Slow switch machines operate slowly to switch a turnout, giving a more prototypical appearance in operation. These fall under two general types:

• Stall motor machines. These typically take power continuously, and are constantly pushing or pulling a turnout. This does not harm the motor or the turnout as the force is very low since the stall current (the peak usage) is around 10mA at 12volts (most brands). Their high gear ratio gives a very slow, smooth movement.
• Momentary contact machines. These machines use power only while they are operating, and rely on their gearing to maintain the turnout position. They generally have some form of screw drive mechanism. They can be very powerful, and use limit switches to control the range of movement. They typically are smaller than the stall motor machines.

[edit] Advantages of slow switch machines:

• Less operating current than snap switches.
• Quiet due to slow moving parts and motor.
• More prototypical speed.

[edit] Disadvantages:

• Larger and heavier than snap motors.
• Lag time between being triggered and the turnout being positioned.

[edit] Slow motion switch machines:

• Tortoise by Circuitron. The manufacturer's web site is Circuitron. See also the American Hobby Distributors web site for this stall motor machine.
• Switchmaster Large under-roadbed can motor with swing arm link
• Aspen Models sells a very small momentary contact screw drive machine.
• NiTiNol Switches - Home made cheap slow motion switch machine made from NiTiNol (Memory Wire). Note: These systems use 200 mA of current while the turnout is thrown- check the rating of any decoder used to be sure you won't burn it out!
• SwitchTender by MicroMark.

[edit] Snap Switch Machines

Snap switches typically "snap" a switch into position. That is, they almost instantly change the position of a turnout switch. Most are a simple latching solenoid and use momentary contacts. This is the type of switch machine you usually find "built into" turnouts.

[edit] Advantages of snap switches:

• Instant turnout control
• Fairly simple to set up a "matrix" to throw multiple turnouts.

[edit] Disadvantages of snap switches:

• Loud
• Quick jolts can sometimes displace the track (???)
• Need large surge of current to operate, particularly when throwing multiple turnouts
• The coil can be destroyed if someone holds the pushbutton down. They are designed to be energized for only a second, not continuously
• Some switch machines can be quite large, requiring under table mounting.

[edit] Brands of snap switch machines:

[edit] ATLAS

• Atlas RR
• http://www.atlasrr.com/

[edit] KATO

• Kato/USA

[edit] N-scale Kato Turnouts

The Kato Turnout is moved by a Turnout Motor. It's a tiny solenoid, hidden under and inside the ballast strip. The Turnout Motor runs on DC (Direct Current). This is different than the common Atlas turnout motor, which will run on DC or AC (Alternating Current).

Because the Turnout Motor runs on DC, it only needs 2 wires connected to it. To throw the turnout, one wire ('A') is positive and the other ('B') is negative; going in the other direction 'A' is negative and 'B' is positive.

The Turnout Motor is only fed electricity for the moment it takes to move the points.

[edit] Controlling the Turnout

The Kato turnouts can be controlled manually or electrically. There is a manual lever poking out of the ballast strip next to the free end of the point rails. There are 2 ways to electrify the Kato switches:

[edit] (a) The Official way

Use the official Kato #24-840 Turnout Controllers, and the #24-842 DC Converter (ie Power Adapter).

The DC Converter (Power Adapter) is a rectifier. Physically, it is a little box with wires on one edge, and 2 snap connectors (very much like the ones on a 9v battery) on one side. The wires connect to the AC terminals of your power pack, and DC is fed out of the snap connectors.

The Turnout Controllers are blue plastic electrical switches. Snap connectors on both sides (male on one, female on the other) allow a row of controllers to be snapped together. The DC Converter is snapped to the left side of the first controller in a row to supply electricity to the entire row. A socket on the back mates with the plug on the cord from the turnout motor.

The Turnout Controller is a momentary contact Double Pole, Double Throw (DPDT) switch. As you move the control from one position to the other, contact is made for a brief fraction of a second, sending DC current to the Turnout Motor.

[edit] (b) The Other way

The "other" way: You can use MOMENTARY CONTACT double-pole, double-throw switches (with MomentaryOn / Off / MomentaryOn positions). They are wired the same way a reversing switch for track power is wired, but the power coming in is fixed DC (Direct Current) from your power pack, and the power goes out to the Kato turnout connector. You'll have to cannibalize a Kato power cord to get the connector. This lets you pick a MOMENTARY CONTACT DPDT switch that you can mount on your control panel.

NOTICE: IF you use the Unofficial Way, YOU MUST use a MOMENTARY toggle switch! If you use a plain, ordinary toggle switch, you'll burn out the turnout motor!!! And have just a manual turnout.

If you look at the back of the momentary double-pole, double-throw, center-off toggle switch, it has 6 electrical terminals: 3 pairs of 2 terminals. Hold the momentary toggle switch so there are 3 rows of 2 terminals. It is wired the same as you would wire a reversing toggle switch for track feed. Connect the center 2 contacts to the auxiliary DC (Direct Current) terminals of your power pack.

The remaining four contacts are wired as follows: Connect 2 short wires across the 'diagonals' of the momentary toggle switch: from upper-left to lower-right, and from upper-right to lower-left. Wires to the turnout motor connect to the upper-left and upper-right contacts.

Since a switch doesn't care about polarity, it doesn't matter which pair of wires goes to the track, and which pair goes to the DC Power supply.

This re-creates the effect of the Kato controller. When you push the momentary toggle in one direction, wire 'A' is positive and 'B' is negative; pushing the momentary toggle in the other direction, 'A' is negative and 'B' is positive. When you mount the momentary toggle switch in your control panel, you can turn it around so the toggle moves in a logical direction.

Concerning the wires heading for the turnout: you'll probably need to sacrifice a Kato extension cord to get the female connector that mates with the connector that powers the turnout motor. If you're -really- brave, you can sacrifice the connector on the turnout and just connect the wires. However, being able to unplug things has a certain amount of convenience.

The problem with using a momentary toggle switch is that you can't tell which direction the turnout is in after it's thrown-- the position of the toggle switch is always in the center. IF YOU INSERT A MOMENTARY PUSH BUTTON (ie doorbell button) IN ONE OF THE LEADS FROM THE POWERPACK, you can use a normal (non-momentary) DPDT toggle switch. And the position of the handle will point in the direction the turnout is thrown. You will move the toggle switch to the desired position, then push the momentary push button.

The drawback with this is that you have to throw the toggle then press the button. But the toggle does represent the position of the turnout. IF YOU DON'T USE THE MOMENTARY PUSHBUTTON IN SERIES YOU'LL BURN OUT THE KATO TURNOUT MOTOR!! You could make the toggle switch a 3PDT (Three-pole, Double-throw) switch, and use the additional contacts to control the panel lights.

One possible advantage of the switch/pushbutton combination is that you could wire it so the one button controls a whole bank of switches: flip a dozen or more toggles, press one button, and watch the layout walk across the floor as all of the turnout points thud against the stock rails at the same time. Your power supply may not be up to it though... (:

IF YOU BURN OUT YOUR TURNOUT MOTOR BECAUSE YOU DID NOT USE A MOMENTARY SWITCH IN THE CIRCUIT, IT'S YOUR TOUGH LUCK FOR NOT FOLLOWING INSTRUCTIONS!

You've been warned!

There are several circuit ideas out on the web that will light up appropriate indicators while allowing you to use a momentary DPDT switch. Start with http://www.awrr.com/indicator.html.

It is not necessary to have a power supply for every 6 turnouts. You should be able to plug a large number of Kato controllers together (or wire an equally large number using momentary switches) without problems, as long as you only throw one or two turnouts at once. The problem is when you try to throw all of the turnouts at once-- the power supply won't be able to handle the drain.

[edit] INSIDE THE KATO TURNOUT CONTROL SWITCH #24-840

(some have number 20-500 molded on the side)

There is no conventional switch in there!

The controller is clamped together by the male and female snaps on the outside and 2 metal posts inside the shell. The female snap is swaged to the post. The post slips into the right half-shell, and the snap fits into a socket; it won't slip through the shell. A clip on each post keeps it from falling back out and keeps it standing straight during assembly, After the left half-shell is placed over the controller, 2 teensy screws hold the male snaps to the posts, and clamp the controller together.

Back inside, the female plug (the one that mates with the cable that heads to the turnout motor) fits into molded guides at the back of the controller. 2 springy wires connect to the plug, and describe a U-shaped path, with one wire on the 'North' side of the 2 posts, and the other on the 'South' side.

A complicated-looking pivoting Thingy between the posts grips the wires. The control handle is a separate piece, and wiggles the Thingy either clockwise or counter-clockwise. As the Thingy moves, one wire is pushed against post "A" while the other is pushed against post "B." In one direction wire 1 touches post A, and 2 touches B, in the other wire 2 touches post A and 1 touches B.

A tiny cylinder slips over a post on the Thingy to reduce friction between the Thingy and the control handle.

A simple yet elegant way to build a switch! And the person who designed the "Thingy" is amazing!

[edit] INSIDE THE KATO POWER ADAPTER #24-842

(some have number 20-504 molded on the side)

This is a lot simpler-- Inside the case is small circuit board with 4 diodes mounted on it-- a standard bridge rectifier circuit. The circuit fits into the base of the case. The lid fits over the circuit board, and 2 female snaps fit through the lid. Two teensy screws clamp the snaps to the circuit board and the back of the case, and also hold the lid shut. The case indicates 17 volts AC in (via wires), and 12 volts DC out (via the snaps).

Because it's a bridge rectifier, you can feed it with DC if you like, and the correct polarity power will show up at the snaps.

[edit] How a DPDT Reversing Switch Works

An electrical switch can be either Continuous contact or Momentary contact. Examples: Continuous-- a light switch, one position is ON, the other is OFF. Momentary-- a doorbuzzer button, the buzzer only buzzes when your finger is pushing the button.

A simple on-off switch is a Single-Pole, Single-Throw (SPST) switch. Power comes in on a single wire, and can leave by another. The switch provides a mechanism that allows you to join the 2 wires with a piece of metal, completing the circuit.

A Double-Pole, Double-Throw (DPDT) switch consists of 2 switches (Double-Pole), each of which can complete 2 circuits (Double-Throw). The 2 switches (Poles) are joined internally and can not be operated independently. Within each pole, power comes in on a single wire (the Common wire), and can leave by 2 different routes. The switch provides a mechanism that allows you to connect the Common wire to either of the other 2 wires.

Double-throw switches come in several flavors: 2 "ON" positions; 2 "ON" positions and a center "OFF" position; and Momentary "ON" / "OFF" / Momentary "ON." This third type is what we need to control Kato Unitrack turnout motors.

The diagrams show the switch in its 2 "ON" positions. Power arrives via the wires connected to the center (Common) pair of terminals.

Depending on the position of the switch, internal connections link power to the top terminals, leading to the turnout motor, or to the bottom terminals.

If power is connected to the bottom terminals, it flows acros the "X" wires to the top terminal on the -opposite- side, reversing the polarity of the power (ie the Red and Blue are reversed).

It doesn't matter if you swap the 2 pair of wires leading to the switch; it functions just the same if the wires connected to the common terminals go to the turnout motor and the top terminals are connected to the power pack.

PaulMmn@ix.netcom.com --12.203.80.245 22:10, 10 March 2006 (EST)

[edit] Stationary Decoders

Below is a selection of stationary decoders which can handle turnout motors, broken down by manufacturer.

The products listed below are capable of handling turnout motors. However, most products are capable of other tasks such as block detection, push button control, etc. Please see the various manufacturers products pages and manuals for further details.

[edit] Digitrax

See Digitrax Products page for full details on Digitrax's products.

• DS64 - Controls snap and slow motors. Operate your turnouts directly through any DCC system that has turnout control.
• DS44 - Basic quad stationary decoder for slow motion turnout machines
  • Cheapest per turnout, but operates only via throttle commands (and/or computer).
• DS51K1 - Stationary decoder for single kato unitrack turnouts
• DS52 - Dual stationary decoder for bi-polar, snap switches, or slow motion machines
• DS54 - Quad stationary decoder for snap switches or slow motion machines. Has 4 outputs & 8 inputs which be used for positive feedback of switch position, or other uses.
  • Older brother to the DS64.
  • DM1 - DC motor adapter for use with DS54

[edit] Lenz

[edit] LS100 and LS110

• 4 DC Outputs with common positive
• Momentary (0.1 to 15 seconds), Continuous and Flashing (4 to 0.5 Hz) options
• Always programmed to a group of 4 turnout addresses. e.g. 1-4, 5-8, 9-12
• Can use DCC track power or external supply

LS100 and LS110 are identical except the LS100 supports the Lenz RS Feedback Bus

With the addition of LA010 output adapter the 3 wire common poitive can be converted to a two wire polarity reversing output. A circuit to do the same job as an LA010 is on the Lenz Accessories page

[edit] LS150

• 6 AC Outputs for twin-coil snap action
• Motorized switch machine like KATO Unitrack turnouts can be used with simple addition of 2 diodes.
• Each output can be given an individual 'Turnout address'
• Outputs can be set to be on for 0.1 to 10 seconds
• Needs external AC supply - Max 16 V (Use a transformer LESS than 45VA or add a 10Ω resistor)

[edit] NCE

[edit] Wiring Stationary Decoders

Hints, tips, and suggestions on wiring stationary decoders for use with turnout control.

[edit] Using A Separate Booster

...Or at least a seperate run from a power management device for controlling your turnouts with DCC stationary decoders. The reason is simple. If the turnout stationary decoder is powered by your track bus, and the movement of the turnout shorts out your trackbus, the movement of the turnout will stop. Because the turnout motion stopped, the short will never clear itself. If the turnout was powered by a seperate buss, then there would be a temporary short on the track, but power would automatically be restored once the short clears.

Keep in mind, that any bus lengths over 30' feet should be twisted and buss ends should be terminated. Please see the track wiring pages for details.