DC Power Tortoise point motors

[danphi11ips]

Good Afternoon All,

Thank you for your continued help and support. Sorry for all the questions.

 

I am currently wiring my control panel to work with Tortoise point motors. I am using a Hornby standard controller to give the 12V DC input and I would like to power 13 point motors in the diagram attached (sorry, I'm not a very good artist!) I believe that the standard controller is not powerful to power the 13 motors plus Grain of Wheat Bulbs. I would also like to power lights on the station, yard, and a few DIY auto-unncouplers. Is there anything that I can purchase which would power all of this or do I need multiple inputs?

 

Thanks a lot

Dan Phillips

 

Good Afternoon All,

Thank you for your continued help and support. Sorry for all the questions.

 

I am currently wiring my control panel to work with Tortoise point motors. I am using a Hornby standard controller to give the 12V DC input and I would like to power 13 point motors in the diagram attached (sorry, I'm not a very good artist!) I believe that the standard controller is not powerful to power the 13 motors plus Grain of Wheat Bulbs. I would also like to power lights on the station, yard, and a few DIY auto-unncouplers. Is there anything that I can purchase which would power all of this or do I need multiple inputs?

 

Thanks a lot

Dan Phillips

[jamie92208]

That circuit would work but I'd replace the Grain of wheat bulbs by 12v LED's which take a lot less current.   How many motors you can power depends on the power output of the controller.  On my last layout I used a 1.5 amp transformer giving out 16Vac and then into a bridge rectifier.  (5 for less than £2 at RS) this gave about 17vdc.  By the time I had got 110 motors and several relays wired up the voltage was down to about 13.  That didn't worry the tortoises as they will work down to about 8. 

 

Jamie

[66C]

Hi Dan

 

OK - sounds obvious - but have you looked the diagram in the Tortoise instructions that shows how to wire LEDs into the operating wiring?

 

This is available online here:

 

http://www.circuitron.com/index_files/ins/800-6000ins.pdf

 

Circuitron also have an application note here:

 

http://www.circuitron.com/index_files/AN/AN-6000-07.pdf

 

Very little else in the way of wiring is needed using this method and there is no extra power draw!

 

Regards.

[cpman46]

Tortoise motors consume approx 16 to 20 mA when stalled so your 13 would consume approx 0.26A. As mentioned above use LEDs as per the Tortoise instructions. GOW bulbs take 60 to 80 mA each!! Bicolour LEDs available from Rapid and numerous sources on eBay in both 3mm and 5mm diameter versions.

 

What are your lights in the station, yard? I'm guessing GOW so your current consuption will be of the order of 'x' times 60 mA where 'x' is the number of bulbs. Need to add this to your Tortoise consumption.

 

DIY auto decouplers - I'm assuming electromagnets. What is their resistance? I know their operation will only be intermittent (couple of seconds while you press the button) but if their resistance is about 6 ohms then the power draw will be about 2 amps from a 12V supply whilst operated. This needs to be added to your other consumptions or you may find the output of your supply limiting and dropping sufficiently to dim your lights. The effect on the motors will probably be minimal. Without knowing the output of your controller a 'suck it and see' trial will show whether or not this is the case.

 

Regards

[danphi11ips]

Thank you for all your replies, Jamie,I'll look into a bridge rectifier and I didn't realise GOW bulbs used so much power. I'll look at replacing them. 

 

Thanks Bill, I have looked at the diagram but I found that the LEDs only are lit when the point is in motion and they go out afterwards- I'd ideally like them to stay on permanently. 

 

Mike, the station bulbs are also GOW but these can be replaced to be LED easily. The uncouplers I was going to make are these http://www.newrailwaymodellers.co.uk/Forums/viewtopic.php?t=7130 if that is any use. 

I don't know what power the controller is, only that it's a standard Hornby controller that's 12V DC. 

 

I hope this helps

Dan

[cpman46]

Dan

 

If the controller is already dc output then a bridge rectifier is not required. As Jamie said he was using it with the ac output of a 16V transformer to give him a full wave rectified supply.

 

I'm not sure what tortoise diagram you looked at but my copy shows the back to back LEDs in series with the motor in one of the leads from the switch. As wired they will dim as the motor runs but will return to normal brightness as the motor stops because the motor still consumes about 16mA when stationary. I have editted your diagram to show the connection to the LEDs. One LED will illuminate at one end of the motor travel and the other will be illuminated at the other end of the motor's travel.

 

 

With your uncoupler using the Peco point motors described I think you will draw at least 2A momentarily from the supply. I think the coil resistance will be somewhere between 4 and 6 ohms.

 

I would definitely replace the GOW bulbs in the station and yard to reduce the current consumption but remember to add the appropriate series resistor(s) to limit the LED current.

 

Mike

[jamie92208]

Dan

 

If the controller is already dc output then a bridge rectifier is not required. As Jamie said he was using it with the ac output of a 16V transformer to give him a full wave rectified supply.

.

 

Can I echo that Dan.  I think it would be better to have your own small transformer of known output rather than relying on the uncertain output of the Hornby unit.  A small 2 amp 16Vac transformer will only cost about£10 to £12 from RS or Maplins.  if you need a stock code let me know.   Put that and the rectifier in your control panel and then everything is self contained.

 

Jamie

[danphi11ips]

Thank you both for your help and advise

 

Would thee LEDs be sufficent? http://www.ebay.co.uk/itm/50pcs-Ultra-Bright-3mm-LED-Light-Lamp-Bulb-80000mcd-White-Blue-Red-Green-Yellow-/300817717605?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item460a221965

 

Also, Would I be better off buying a 1 amp 16V AC transformer and a rectifier or a 12V DC transformer?

 

Sorry for all the questions, I'm relatively new to electronics!

 

Thanks
Dan

[jamie92208]

Hi I would get a 2 amp transformer.  It's better to run a slight;y larger thing at less load than risk overloading a small one and the extra cost is minimal.   As to a 12v transformer it is possible to buy a ready made power pack that gives a couple of amps at 12 v dc at places like Maplins and it would save you the hassle of wiring up the transformer and then protecting the 240v wiring.   I use one of those power packs in one of my control, panels to provide a seperate stabilised supply for the signals.

 

Technically a transformer on its own will always give you an AC output that then needs to be rectiified to provide a DC ouptut usually with a small square thing with 4 leads on it called a bridge rectifier.   These four terminals are two marked with an ~ which you connect your AC output from the Transformer to, and the other two amrked + and - which are your DC output.  They often have a hole in the centre so that you can screw them to a mount, such as the side of the panel.   They are rated in VA which is the volts and amps so for your application 2 amps at 16v would need at least a 32VA.  Again it is better to buy a larger one and run it well within it's capacity eg 50 or 100VA.

 

Jamie

[cpman46]

Dan

 

Don't apologise for asking questions. We all started from the same base and knowledge is gained by asking those with experience.

 

I think the LEDs will be overly bright for your application. Personally I would use standard 5mm diffused package ones e.g. Rapid 55-0120 Green, 55-0155 Red. These will be more than bright enough for a panel display. For the station and yard I would suggest a warm white LED or even yellow depending on the era you are trying to portray.

 

You will need the 2A 16V ac transformer at least to give you enough power for your Tortoises, magnetic decouplers, lighting.

 

There is no such thing as a dc transformer. Transformers are used in our case to step down the 240V ac mains to a lower voltage and provide isolation. You can have a dc supply but this will comprise an ac transformer plus components to rectify the ac and possibly capacitors and other components to regulate the output.

 

With respect to Jamie I would not put the transformer in your panel. I prefer to have mine in a separate earthed metal box or an insulated plastic enclosure to keep the 240V ac mains well away. The low voltage ac output or rectified output if you include the rectifier in the same box is then fed to you panel/layout using suitable low voltage connectors and cabling.

 

If you are not experienced in mains wiring I would strongly suggest buying a ready cased transformer or power pack as suggested by Jamie.

 

Mike

[danphi11ips]

Thank you both for your continued support. I'm searching ebay and can't seem to find the suggested LEDs. Would you also mind providing a link to a sufficient transformer. Understand what you mean about having it in a insulated plastic case.

 

Thanks a lot

Dan

[Brian]

Hi
This ebay 12 volt regulated 1.0Amp power supply would amply feed some 60 Tortoise motors though then with that number I would use the 2.0Amp power supply below.   Average stall current is approx. 16milliamp or 0.016Amp   Therefore  60 stalled would only demand 0.96Amp .
http://www.ebay.co.uk/itm/CCTV-Security-System-Colour-Camera-Power-Supply-1-Amp-Regulated-12-Volt-DC-PSU-/251284992582?pt=UK_CCTV&hash=item3a81c0b246

This one offers regulated 12 volt dc at 2.0 Amp. Should you want more current...  http://www.ebay.co.uk/itm/CCTV-Security-System-Colour-Camera-Power-Supply-2-Amp-Regulated-12-Volt-DC-PSU-/261045384941?pt=UK_CCTV&hash=item3cc78476ed

 

 

Edit to correct error in URL

[66C]

Hi Dan

 

I think you may have missed the point about wiring the LEDs in series with the Tortoise motor. If wired as suggested the power to the motor is always on and so the LEDs will always be on as well. It does mention this in the Circuitron literature.

 

Regards.

[Brian]

Hi

Further to my post 12 above, these Bi coloured LEDs will work with Tortoise motors, giving Red one way and Green for the other. Just wire them into the feed wire to the Tortoise terminal 1.  http://www.ebay.co.uk/itm/Bi-colour-3mm-LED-Red-and-Green-Pack-of-5-/121093553799?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c31bcfe87   Wrong colour shows? simply swap them around end to end in the feed lead.

Or if you prefer two individual LEDs then these are ideal in the colour choice you require (e.g. Red and Green) http://www.ebay.co.uk/itm/10X-Super-Bright-3mm-LED-Multiple-Selection-of-Colours-pack-of-10-UK-Stock-/271288949293?pt=UK_BOI_Electrical_Components_Supplies_ET&var=570193934549&hash=item3f2a14da2d    Wire them both into the one feed lead to Tortoise No 1 terminal and connect the longer lead of one LED to the shorter lead of the other and the same with the other two leads long to short. Again if they light to the wrong colour i.e. green v red, then simply swap the pair around in the feed lead.

No additional resistors are needed if they are wired into the No1 feed lead. 

[danphi11ips]

Thank you both for your help. I have purchased a 12v 1.0Amp tranformer. and the appropriate bulbs from ebay.

 

Thanks again

Dan

[kevinlms]

Thank you both for your help. I have purchased a 12v 1.0Amp tranformer. and the appropriate bulbs from ebay.

 

Thanks again

Dan

Bulbs? Or LED's?

[danphi11ips]

LEDs!!

 

Sorry for the confusion!

 

Dan

[danphi11ips]

Good Evening All,

I have done as was suggested above and currently have 7 point motors wired (3 crossovers) so 4 switches, each with 2 Bi-colour LEDs. However, the LEDs keep blowing. I have replaced 8 today. On many of them one of the colours doesn't work yet with a new LED it's fine. I have just had two that blue on the same circuit simultaneously. Is there something that I am doing wrong? Or are the bulbs just very delicate?

 

Thanks

Dan

[corax67]

Hi Dan - if you have bought 12v LEDs then the Tortoise shouldn't be blowing them. I use multiple LEDs as route indicators on my own fiddle yard operated via the switches on my Tortoise motors and have yet to experience a failure.

 

Any chance of a picture so we can see how everything is wired and we can hopefully remedy your problem in short order

[danphi11ips]

Hi Karl, Thank you for your reply. The wiring is exactly the same as Mike's diagram and they are 12V LEDs. I am not sure if they may be very delicate as I have been moving them around. What would you like a picture of?

 

Thanks a lot

Dan

[danphi11ips]

Just to add, these are the LEDs which I have http://www.ebay.co.uk/itm/121093553799?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

 They were recommended on this page.

 

Thanks

Dan

[newbryford]

The LED's you have linked to aren't 12v - they are "normal" ones with 2v one way and 2.2v the other. They should work fine.

 

Cheers,

Mick

[Brian]

Hi

You shouldn't use 12 volt rated LEDs when placed in series with one operating wire of a Tortoise motor.

These 12 volt rated LEDs have an internal resistor to allow for the direct 12 volt working and this could easily blow due to the current being passed through it by the Tortoise motor running and stalled current.

 

The correct type of LED are the 2.0 to 2.2 type shown.

The Tortoise motors coil, which is approx., 600 OHMs, offers the LED the current limiting resistance needed for a LED running from a nominal 12 volts dc.   (Approx 0.016ma)

 

Note: The LED(s) are not across (In parallel) to the feed wires but are in series with one of feed wires to pin 1 or 8

[Gordon H]

I think you mean 16mA, not 16uA.

[Crosland]

Hi

You shouldn't use 12 volt rated LEDs when placed in series with one operating wire of a Tortoise motor.

These 12 volt rated LEDs have an internal resistor to allow for the direct 12 volt working and this could easily blow due to the current being passed through it by the Tortoise motor running and stalled current.

 

Not so.

 

The correct type of LED are the 2.0 to 2.2 type shown.

The Tortoise motors coil, which is approx., 600 OHMs, offers the LED the current limiting resistance needed for a LED running from a nominal 12 volts dc.   (Approx 0.016ma)

 

Note: The LED(s) are not across (In parallel) to the feed wires but are in series with one of feed wires to pin 1 or 8

You have shown yourself that a tortoise limits the current to a safe level for an LED at normal supply voltage.

 

Conecting a 12V LED, which is a normal LED with a series resistor, will be quite happy with that current and will not blow anything. All you need to do is increase the supply voltage high enough to give 12V across the LED/resistor and 12V across the tortoise, i.e. 24V.

 

Andrew