Brian Posted November 11, 2013 Share Posted November 11, 2013 Hi AndrewI'm not agreeing nor disagreeing. But what is the wattage rating of the resistor used in a 12 volt rated LED? It can't be very large as its inside the LED package. Hence my recommendation not to use them. In fact Circuitron advise against fitting any series resistors, which is what a 12 volt rated LED will have inside it. http://www.circuitron.com/index_files/AN/AN-6000-07.pdfWhy increase the voltage supply used to power a Tortoise just to illuminate a LED? When a 2 to 2.2 volt LED with ideally a regulated 12 volt PSU is all that's needed. Edit to add link Link to post Share on other sites More sharing options...
Brian Posted November 11, 2013 Share Posted November 11, 2013 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 Hi Dan Just thought... You say you have some Tortoises working as pairs from one switch. Have you wired just one LED into each of these pair of motors feeds or do you have two LEDs in total - one in each motor feed? My thought is that if perhaps two motors are being fed via one LED their combined current may be too greater loading for the LEDs hence they fail? Link to post Share on other sites More sharing options...
Crosland Posted November 11, 2013 Share Posted November 11, 2013 Hi Andrew I'm not agreeing nor disagreeing. But what is the wattage rating of the resistor used in a 12 volt rated LED? It can't be very large as its inside the LED package. Hence my recommendation not to use them. Clearly the rating is sufficient for use at 12V. In fact Circuitron advise against fitting any series resistors, which is what a 12 volt rated LED will have inside it. http://www.circuitron.com/index_files/AN/AN-6000-07.pdf Why increase the voltage supply used to power a Tortoise just to illuminate a LED? When a 2 to 2.2 volt LED with ideally a regulated 12 volt PSU is all that's needed. Edit to add link I'm not saying it's recommended, just trying to help out someone who I thought had 12v LEDs to hand. Andrew Link to post Share on other sites More sharing options...
Brian Posted November 11, 2013 Share Posted November 11, 2013 Dan. I have drawn a simple wiring diagram showning one switch one motor one LED and then one switch two motors plus two LEDs - one LED for each motor. http://i95.photobucket.com/albums/l147/Brianlambert/TortoiuseLEDs_zps5b4059bd.jpg Note in the two motor configuration each motor is fed from the switches tags to its own LED then onto the motor. Hope its understandable? Link to post Share on other sites More sharing options...
Brian Posted November 11, 2013 Share Posted November 11, 2013 Clearly the rating is sufficient for use at 12V. I'm not saying it's recommended, just trying to help out someone who I thought had 12v LEDs to hand. Andrew Clearly the wattage rating is suitable for the LEDs needs at 12 volts - Say some 15 milliamp. But the resistor wattage rating will be very low, quite possibly it will be unable to withstand the current of the LED plus the added current of the Tortoise when its running or stalled? As I said, what is their wattage?? We dont think we know! But I bet LED manufactures wont use a resistor wattage that is higher than needed for the LED. I too am trying my best to help! Link to post Share on other sites More sharing options...
Suzie Posted November 11, 2013 Share Posted November 11, 2013 Clearly the wattage rating is suitable for the LEDs needs at 12 volts - Say some 15 milliamp. But the resistor wattage rating will be very low, quite possibly it will be unable to withstand the current of the LED plus the added current of the Tortoise when its running or stalled? As I said, what is their wattage?? We dont think we know! But I bet LED manufactures wont use a resistor wattage that is higher than needed for the LED. I too am trying my best to help! You are not helping much by persisting with your inaccuracy. The resistor integrated in to a 12V LED in series with a tortoise will not be carrying any additional current therefore will not dissipate any more power. Link to post Share on other sites More sharing options...
Brian Posted November 12, 2013 Share Posted November 12, 2013 Im so sorry about being inaccurate. I notice plenty of criticism is able to be posted but no actual help offered to the OP by the last few posters! Edit at 15 57 12-11-13 to make better sense of first comment. Link to post Share on other sites More sharing options...
Suzie Posted November 12, 2013 Share Posted November 12, 2013 The OP had his answer in post 6, there is no more to add other than counter the dis-information about items the OP has not bought and is not using. Link to post Share on other sites More sharing options...
Brian Posted November 12, 2013 Share Posted November 12, 2013 I Agree re post 6, I was at some stages responding to the 12 volt LED reference, but my main reply was to the OP, see his Post 18. My replies posts 27 & 29 refer. Why is the OP LEDs blowing or not illuminating in one direction? I suspect possibly they are not wired quite correctly, is the LED passing too much current somehow and blowing? As someone mentioned using 12 volt rated LEDs, which obviously have a series resistor built inside them I replied.... Tortoise (Circuitron) specifially do not recommend having any additional resistance in circuit! I recommended the original LEDs via a link which are standard 2.0 / 2.2 volt dual coloured ones and should work well with a Tortoise without anything else needed. Period! Just trying to help get the problem resolved. Not cause mayhem or anything else! A misunderstanding with resistors in series was though my error. Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted November 12, 2013 RMweb Premium Share Posted November 12, 2013 I Agree re post 6, I was at some stages responding to the 12 volt LED reference, but my main reply was to the OP, see his Post 18. My replies posts 27 & 29 refer. Why is the OP LEDs blowing or not illuminating in one direction? I suspect possibly they are not wired quite correctly, is the LED passing too much current somehow and blowing? I would agree that something is seriously wrong with the wiring method the OP has used, if his blowing LED's and/or not working in the reverse direction. This indicates a diode effect of sorts, exactly what's wrong is unclear, as post 20 claims that the wiring is the same as that in post 6. Clearly it isn't so, otherwise the circuit would be working fine. The OP in post 1, mentioned wiring up some powered uncouplers FROM THE SAME POWER SUPPLY, this is possibly the cause of his problems, if that's what his done. The BEMF from these could be killing the LED's. Don't know for sure, just presenting a possible reason for the LED's blowing. I agree with others that the internal resistor of the 12v LED's wouldn't cause blowing. Link to post Share on other sites More sharing options...
Crosland Posted November 12, 2013 Share Posted November 12, 2013 Clearly the wattage rating is suitable for the LEDs needs at 12 volts - Say some 15 milliamp. But the resistor wattage rating will be very low, quite possibly it will be unable to withstand the current of the LED plus the added current of the Tortoise when its running or stalled? As I said, what is their wattage?? We dont think we know! But I bet LED manufactures wont use a resistor wattage that is higher than needed for the LED. I too am trying my best to help! The components are in series. The same current flows through the LED, resistor and tortoise. The tortoise stall current (16mA) is within the current rating of the LED/resistor. Running current will be lower due to the effect of Back EMF from the motor. Adding a tortoise to the circuit does not add extra current. In fact it will reduce the current unless you increase the supply voltage to compensate for the extra resistance in the circuit. Andrew Link to post Share on other sites More sharing options...
Crosland Posted November 12, 2013 Share Posted November 12, 2013 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. 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 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. Did you use the wiring diagram from your first post, which originally used GOW bulbs? If so, that is the cause of the blowing LEDs. They are wired in parallel with the motor and if they are not 12V LEDs, or do not have a current limit resistor, they will blow. Andrew Link to post Share on other sites More sharing options...
Brian Posted November 12, 2013 Share Posted November 12, 2013 The components are in series. The same current flows through the LED, resistor and tortoise. The tortoise stall current (16mA) is within the current rating of the LED/resistor. Running current will be lower due to the effect of Back EMF from the motor. Adding a tortoise to the circuit does not add extra current. In fact it will reduce the current unless you increase the supply voltage to compensate for the extra resistance in the circuit. Andrew Hi Yes I know all about current flow and resistors in series etc ! I apologised in posts No. 32 (badly when I reread it!) and again and more specifically in the last sentance last paragraph of my post No. 34. So there was no need to raise it yet again! Heaven forbid anyone ever made a series serious error on the forum, I can see henchmen turning up in the middle of the night and gallows erected ;-) Now lets leave series resistors and 12 volt LEDs etc alone and hopefully resolve the main issue.... If the LEDs have been wired across the supply wires to 1 and 8 terminals of the Tortoise this is indeed why they have failed. A simple drawing was supplied in post No 6 and I too provided a similar one but showing two motors from one switch in post No 29. All of these should help there OP understand how to wire the LEDs and motor(s). Dan the OP appears only to come onto the forum in the evenings by his previous posts in this topic, so hopefully after he has waded through all the previous posts he'll be able to explain more! Link to post Share on other sites More sharing options...
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