Points motor LED

[Swerveq]

Is it possible to run red and green LEDs from an on/off/on points switch as a visual check from a control panel.

If so, is a resistor required?

[jane1707819582]

Yes it is , you will need to retain (latch) the signal when you activate the switch to maintain the led in the on state

 And yes you will need a current limiting resistor with the led,unless you purchase one which has an integral one fitted .

[St1ngr4y]

If they are solenoid point motors, would that not burn them out?

 

Ray

[walkingthedog]

And if a CDU is fitted wouldn't that destroy the LEDs?

[Chrissaf]

If so, is a resistor required?

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LEDs need to have current limiting on their supplying power, else they will burn out. The simplest form of current limiting is to use a series wired resistor. Either LED leg, it doesn't matter, but convention usually places the resistor in the positive LED leg. Some LEDs that are marketed as being 12 volts, usually have the resistor built into them, but your standard LED is typically 1.7v to 2.1v for the Red colour and 2.0 to 3.0 volts for a Green colour.

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Assuming a 12 volt power supply, then a 1,000 Ohm resistor will limit the current to about 10mA which is ideal for most LEDs.

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With regard your text:

 

.....from an on/off/on points switch.....

 

this is a rather vague line in your question text.

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1. Do you mean, the switch you actually use to operate the point motor (which should be a non locking momentary action centre off change-over switch).
2. Or do you mean an auxiliary switch (change-over contact) of some kind that is physically linked to the point operation. But not within any part of the electrical circuit that actually operates the point motors.

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If you mean item 1) then you will need to add a 'latching relay' to the circuit to provide a latched change-over contact to operate the LEDs.

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If you mean item 2) then yes you can use it to operate two LEDs to indicate point position. Which will need a separate power supply (not the one you use to operate your point motors with). It is a very simple circuit.....see below.

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/media/tinymce_upload/6fc1182c00f7bebd605f362e92c68193.jpg

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With regard list item 1). If you are not familiar with what a latching relay is or does. Then this image below has been duplicated from a previous forum question. The latching relay in this example is the Gaugemaster GM500 product. Basically a 'latching relay' as the name suggests is operated from the voltage pulse that is used to operate the point, but the relay 'latches' onto the direction it has been operated and locks into that position until the point is operated in the other direction. This means that permanently made change-over contacts can be used on the relay to operate signals and panel indicator LEDs, whilst the actual non locking point operating switch can remain 'open circuit' in its idle position.

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/media/tinymce_upload/ad286e59012e66939fdf07caa105e07a.jpg

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PS - These schematic options eliminate any of the issues that have been voiced by previous posters. Because the LED circuits and point operating circuits are physically separate and/or isolated by the relay.

 

[Swerveq]

.....from an on/off/on points switch.....

 

I think it was suggested in an earlier post that this switch was suitable to operate the Hornby R8243 points motor. I have never used one of these before so am in the dark as to how they operate but am hoping it's flick left for one direction and flick right for the opposite direction.

So, using this switch, is it possible to wire in red and green LEDs to the switch to indicate direction selected?

If this is possible is a resistor still required?

[96RAF]

Have a look here - a how-to for buildng simple signal lights to place at each junction. The article also shows the associated wiring diagram. You could equally well put the basic leds on a mimic board.

http://www.halton96th.org.uk/article5.html

 You will see the solenoid point motor actuates a simple switch to flip the lights from red to green as the points operate. This ensures that the light reflects the point position.

[walkingthedog]

Not just LEDs on their own. The switch only makes a momentary contact  so the LED would just flash on for a fraction of a second. 

[96RAF]

That switch is NOT suitable for solenoid motors. You need a sprung off type (ON)-OFF-(ON) the brackets indicating a sprung function.

As stayed previously you need a separate switch for operating lights than the one used for switching the solenoid. The earlier published diagrams tell you the way to do it. The switch you posted IS sutiable for,lights because as WTD says you need one that stays put when toggled over.

[Chrissaf]

Just to be semantic for a moment.

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The description made about it i.e flick the switch one way and flick the switch the other indicates that the switch that is intended should be the correct momentary action switch.

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The fact that the ( brackets) have been left off the switch "on-off-on" text in the post as written maybe just an oversight by swerveg because he doesn't appreciate the significance of the brackets. I do note however that the ( brackets ) do not appear on the body of the switch in the photo, but that is just an example photograph. If swerveg has ordered a switch that was suggested as suitable from an earlier posted reply, and that reply gave a link to the switch retailer then I would assume that the actual switch ordered via that link is the correct 'momentary action' one.

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Swerveg,

I refer you back to my second wiring schematic in my first reply above.

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Yes you will need a resistor.

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You cannot directly use the switch that operates the points to directly operate the LEDs. The points switch is a 'momentary action' switch and the LEDs need a 'locking switch action', else as WTD says, the LEDs will only flash and not stay on.

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The conversion of 'momentary' to 'locking' action is performed by the latching relay in my second wiring schematic.

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Yes it adds wiring complication, but including mimic panel LED point indicators are always going to add more complication, whatever solution is used.

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If you have not yet purchased the R8243 Hornby surface mounted point motors, then now is the time to stop and reflect on exactly what you want to achieve. If you have not yet purchased your motors, you have the opportunity to purchase a non Hornby brand that includes the change-over switch contacts built into the point motor that could be used instead of a 'latching' relay.

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However, note this. Point motors that have the extra change-over contacts for mimic panel LEDs are under-board mounting and not surface mounted.

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Point motors that come to mind that have the extra change-over contacts are:

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Gaugemaster SEEP PM 1 point motor (or a PM 4 motor)

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/media/tinymce_upload/fadac4b793bbdbf7759a56cd49589c36.jpg

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How to wire the SEEP PM 1 or 4 motor for mimic panel LED working.

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/media/tinymce_upload/5eed72d92fb4c54bd13438c3d441af0f.jpg

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Note that the SEEP PM point motors are extremely sensitive to installation alignment. If they are installed even a degree off the correct alignment then they can stick or more likely the switch contacts will not perform reliably. Alignment and positioning is critical with these point motors. Thus for reliability, the GM500 latching relay (although adds cost) is more likely to give less installation & ongoing issues. The adage of 'you get what you pay for' is never truer than in model railways.

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It is possible to add mechanical (electrical) micro switches to the point operating mechanism, by either gluing a switch to the point motor or through some other self designed methodology. But given the detail in your questions asked so far, this level of modelling skill maybe something you don't yet posses.

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There are other point motors that include integral contacts, but these tend to be of the 'Stall Motor' operation variety. Tortoise motors for example or from the DCC Concepts Cobalt analogue range.

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Simpler Alternative Solution.

 

Another alternative solution to add mimic panel LED point position indicators in a simple manner, is to use a third party electronic circuit board specifically designed for this task. There are a few that I have seen, but this one by Heathcoat Electronics comes to mind. This product, in essence, combines the function of the 'latching relays' in one integrated 'all electronic' circuit board design that negates the need for much of the wiring complexity.

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• One board per four points required.
• Does not require additional resistors either.
• The board can be co-located with the point operating switch mimic panel, so additional LED wires that go back and forth between the mimic panel and the actual physical point location are not required. Adding further to the simple to install methodology.
• Can be used with surface mounted point motors, such as the Hornby R8243 and PECO PL-11, as well as under-board point motors.

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/media/tinymce_upload/2cb7b0347449bcfa96508d32b6dc7b62.jpg

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Simple wiring to install.....see below extract from website link above.

/media/tinymce_upload/62b15d14f65f7bb58020892abb150770.gif

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Price List and Ordering.....£18.40 per board as at today's posted date (includes the 4 red & 4 green LEDs seen in the photo). But worthwhile for those that see the GM500 latching relay circuit schematic as too daunting to contemplate. Not only that, but cheaper as well. The GM500 latching relay is £6, so £24 for four versus £18.40 for a four way PCB board.

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Note that LEDs have a positive and negative side and only light up when wired the correct way round. I notice in the photo that the red and green LEDs are wired in parallel and share the same terminal screws for their wire legs. This tells me that the circuit board uses voltage polarity reversal to light the LEDs. The positive and negative of the red LED will be wired the opposite of the green LED positive and negative. Thus when the screw terminal voltage polarity is one way round, the red LED will light up and the when the screw terminal polarity is reversed the red LED will go out and the green LED will light up instead. I mention this, because if this solution is adopted, care must be taken to get all the LEDs wired the right way round. The long leg of a standard round LED is the positive leg. The flat side of a standard round LED encapsulation is the negative side.....see graphic below.

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/media/tinymce_upload/4cd4a6ea57234e8fdd0983b51b16bef0.jpg

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[Flashbang]

The OP has clearly stated they want or are to use Hornby Surface solenoid motors R8243  Confusion can set in when quoting another make of motor such as Seep PM1 etc!

The R8243 motor cannot have any "add on" switches directly fitted to them.

BTW... If the operating switches shown lever springs back to centre Off from BOTH operating directions under it own spring then it is fine to use with any make of three wire Solenoid point motor.  If it remains in an On position it is not suitable.

For indications there are several options available.  

A) Use a ready made Point Position Indicator (PPI) board as produced by several suppliers and the PP14 is one such from BlockSignalling, but as I say there are others available.  

B) Use a twin coil Latching relay board wired to the motors three feed wires - Gaugemaster GM500 and Brimal MR204 are two examples that work with any three wire solenoid motor.  Note: The GM500D is suitable for use with DCC point accessory decoder operated solenoid motors. 

C) Fit a micro switch to the opposite side of the point from the R8243 so as the points moving stretcher (Tie) bar operates the lever of the micro switch. Such micro switches are obtained from suppliers like Bitsbox item SW158 and of course there are many other suppliers of micro switches too!

 

In all cases a separate power supply is used to feed the LED indications.  Usually this is a 12 volt DC regulated supply.  Basically wire supply Positive to the 'C' contact of a switch or the Change-over contact (Com) and then two wires run to the panel LEDs and connect to the LEDs Anode leads (Longer lead). Joint together the LEDs Cathode leads and run to a 1K0 (1000 ohm) resistor (unless the LEDs are rated at the supply volts then a series resistor is already fitted e.g. 12 volt rated LED).  Connect the other end of the resistor to supply Negative.  Note this is for a single LED illuminating to show the position of the point. i.e. LED lit when that route is set and off when its not and the other routes LED  then illuminates, so only one resistor is need as only one LED can light at any time.

 

Much of what is asked about is shown here if its of help>>>>  https://www.brian-lambert.co.uk/Electrical_Page_3.html#Bookmark6

 

Edit.  I now see that Chris has updated his post to include a PPI from another maker.

[Swerveq]

Many thanks to all, but especially Chrissaf and Flashbang for your very detailed replies. The PPI is definitely the way for me to go with my (very) limited knowledge of electronics but these ready-made units appear to make things look a lot easier.

Hope you don't mind if/when I come back for more advice once I receive the PPI unit.

[Chrissaf]

Which one have you gone for.....Heathcoat or Block Signalling or another?

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I noticed that the Block Signalling one is cheaper per port than Heathcoat as it is 8 way rather than 4 way, but does look slightly more complicated to wire up. The Heathcoat one looks at first glance to be much simpler to install.

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Just so that you are aware. When mounting a standard round LED into a panel (mimic panel). It is much easier to do if you use an LED bezel mount. This is a push in plastic or metal ring with a locking clip. It makes the physical mounting of LEDs a little easier. Round LEDs come in two common types, 3mm diameter and 5mm diameter. So the appropriately sized bezel is required. larger round LEDs are available, but the smaller 3mm / 5mm sizes are more appropriate for a mimic panel.

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Here are some "LED Bezel examples".

 

[morairamike]

There are various ways of doing this. 

If you use SEEP point motors the type 1s have an integral moving electrical contact. Connect your LED to that using the common as the common as per the LED .   Add current limiter as required.

The picture shows how I have wired my layout to give LEDs and signal control. I use the SEEP PM aux contacts to switch my frog polarity, live frog points. Some will say over engineered some will dismiss it but it works for me and the design of circuits is the fun part for me. /media/tinymce_upload/747b48f923a18084ee596f485192a0cf.jpg

[Swerveq]

I'm getting one of each as I have 10 points to wire in. If the Block Signalling one is too complicated I'll get more of the other type.

I can see that the Block Signalling one is a DC supply but can't see the info on that for the Heathcoat. If they are both DC can they both come off the same supply?

[Chrissaf]

If they are both DC can they both come off the same supply?

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Although they both have DC input support (the Heathcoat supports AC input power as well), they can't unfortunately come off the same supply due to the different product power requirements that is specified by the manufacturer on their websites.

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In the drawing below I have tried to morph the two PPI (Point Panel Indicator) wiring requirements from both manufacturers into one wiring schematic diagram. Now my drawing is totally based upon the schematics provided by the two different product manufacturers web pages. The thicker red and black wiring lines in my schematic represents the high current (thicker) wires required by the point motors. These are typically 24/0.2mm or 32/0.2mm wires. The thinner red and black lines in my schematic represent the thinner lower current wires that are fine for the power supply inputs to the two boards. On the 'Block Signalling' PPI only one single point and switch is shown to keep the drawing uncluttered.

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/media/tinymce_upload/6f2e39d55e0e1d9f49e6a6b0fc462398.jpg

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Although both products are PPIs (Panel Point Indicators) their internal circuits function in different ways. The 'Block Signalling' product specifies a separate external 12 volt DC supply that is totally separate from the supply being used to operate the point motors.

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The 'Heathcoat' PPI product on the other hand has a more flexible power input capability in that it is DC or AC and shares the point operating power supply. Note how the Heathcoat product uses a single common negative that is shared between the PPI input power connection and the CDU negative output. Whereas, the Block Signalling has two negative input feeds. One from the CDU for point switching detection and one from the 12 volt power supply for power.

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This is the key reason why both products are unlikely to be able to share the same power supply, not including the difference in voltage i.e 19 volts DC versus 12 volts DC. The 'Heathcoat' PPI supports input power up to 24 Volts DC, double that of the 'Block Signalling' product. And dropping the CDU input supply down to 12 volt DC to suit the 'Block Signalling' product is not a good idea either, as robust solenoid point motor operation is better with the higher CDU input voltage.

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In some ways it is a pity that you chose not to standardise on one manufacturer product as it does complicate the wiring and also means that the additional 12 volt supply needed by the Block Signalling product is an additional cost item.

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I trust that my schematic helps to clarify your understanding of the power wiring requirements.

[morairamike]

Further to my diagram above. Any solenoid point motor can be used. Relay RL1 is a latching so it stays in the last position till fired again. The coil is reversible. The polarity of the supply is changed over by switch 1. The supply is from the CDU. The CDU is supplied from a 240/20 Vac transformer, not shown. The 12v supply is a 240Vac to 12Vdc 5A supply. Not shown

The relay ARL is a normal relay in this case as I happened to have some, but could be a latching in which case it needs to be wired in parallel with RL1. The contacts on the relays can be used for frog polarity switching, signals switching and mimic panel LEDs. The LEDs shown a bi colour.

 

The voltage regulators are 15v max input but are adjustable down to 3v. So the supply to the LEDs can be adjusted. Only your imagination limits the scope of the possibilities.

The components are reasonably priced.

[Swerveq]

I'm thinking that I will probably standardise on either the Heathcote or Blocksignalling product partly because of the different power requirements.

Could you tell me what happens if a lower (or higher) voltage is used instead of that specified by a supplier? For instance 16v AC against 20v AC. 

Also, I notice that AC or DC can be used on the Heathcote product. How is this so?

[Chrissaf]

Also, I notice that AC or DC can be used on the Heathcote product. How is this so?

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Because of this rectification diode (circled in red). This is a common practice used to make a product compatible with AC as well as DC. The DC passes through the diode untouched (the diode just drops 0.6 volts across it). The diode removes the negative half cycle of an AC input so that pulses of positive DC current are passed through to the rest of the circuit. Using a single diode for this is cheap & effective but not that sophisticated, a more sophisticated board would replace the single diode with a full bridge rectifier diode array so that both AC half cycles would be passed through as pulses of positive DC.

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/media/tinymce_upload/2eeb8fe533f2eb613545c45161528822.jpg

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Could you tell me what happens if a lower (or higher) voltage is used instead of that specified by a supplier? For instance 16v AC against 20v AC.

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I would not change the voltages that are recommended by the manufacturers. They are specified for a reason. The 'Block Signalling' product is specified as 12 volts DC only. So that is what you should adhere to if using that product.

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With regard the Heathcote product, things get a little bit more mathematically complicated, but I will try to explain. The Heathcote specifications say 24 volts MAX, they also go on to say that 16 volts should be the max when using AC. This 24 figure does not apply when using AC input voltages, only applies to DC. For why, see below.

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The MAX value if using AC will be much lower than 24 volts. This is because AC voltages are always stated as a RMS (Root Mean Squared) value. There is a mathematical conversion factor of 1.414 to convert AC RMS voltages to their equivalent DC voltages. This 1.414 conversion factor is a documented law of physics when dealing with RMS voltages.

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So taking the recommended 16 Volts AC (MAX) as the input to the Heathcote product, this equates to an equivalent DC input of 16 x 1.414 = 22.62 volts (this is fine because 22.62 is less than 24)

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An input of 20 Volts AC on the other hand = 20 x 1.414 = 28.38 volts which exceeds the 24 volt limit.

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The 16 volts AC voltage is used by Heathcote, because it is a common AC voltage that is found on the Aux output of many old style DC Analogue controllers and used extensively by many railway modellers to operate Solenoid point motors. I would not push my luck and use a 20 volt AC supply.

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[Buz]

Looking at the Hattons set up I would look for a USA ground bi-directional signal head I prefer something that at least looks real, Walthers in the USA usually has that kind of thing

When set up it should show green for the mainline usualy but not always normal (the straight road) and red for reverse usualy but not allways (the diverging road)

regards John