sigtech Posted December 11, 2015 Share Posted December 11, 2015 I have already posted this information on my blog (Sproston), along with the photos, but thought I should air this topic fully - in the hope that someone with far more knowledge than myself might clarify any false assumptions I have made. I am in the process of trying to use three spare 'Seep' PM1 point motors as slaves to repeat the indications of points in the hidden sidings on SPROSTON, retrofitting led's to the panel. The points in question use 'Peco' surface-mounted motors - purchased after I realized there was no real need to mount them beneath the baseboard, however these do not have any contacts for this purpose. I have fitted the 12v leds into the panel fed from a 12v dc (uncontrolled) supply on the 'Gaugemaster' controller- wiring all the negatives together and running this wire back to the 12dc (uncontrolled) negative terminal block. The positive path runs from 12 dc(uncontrolled) terminal block to terminal F on each of the Seep PM1 - which according to the instructions is "common" to terminals D and E, from these terminals separate wires run to each of the respective positive legs of the six leds, to indicate normal or reverse lay of the points. I thought this would work - but on power-up I got an immediate short-circuit and so far have not found the cause - hence my request for help from the RMWEB community. My questions are 1. Is it o.k to use a DC supply on the Seep PM1 auxiliary contacts ( the point operating circuit is 16v AC using a capacitor discharge unit.)? 2. Have I just misunderstood how contacts D and E function with F? 3. Have I got part of the circuit construction wrong in some way using the led's - and should they be 12v? Any help would be gratefully received - as I can see that the next task will probably involve disconnections and using the multimeter!!! Thanks in anticipation, Regards SIGTECH (Steve). Link to post Share on other sites More sharing options...
jamesg Posted December 12, 2015 Share Posted December 12, 2015 Dear Steve,Your wiring diagram is very clear and looks correct, a couple of points to look at though:* Are the common contacts on the point motors (C on the PM1, black on the surface mount motors) all connected to the common/negative output of the CDU? They should be connected to the CDU, not the controller's AC output.* Are the coil contacts (A & B on the PM1, green and red on the surface mount motors) connected, via sprung switches, to the positive output of the CDU?Contacts A, B & C are electrically isolated from contacts D, E & F on the PM1. The point motor coils should be isolated from the controller's AC output by the CDU.If the motors are already connected like this, I would start disconnecting parts of the system to isolate the fault. Start with the DC output from the controller, then the AC output from the controller. If the fault is on the AC circuit, try disconnecting the common contacts from each set of point motors. This should help you get to the cause of the problem quickly.Good luck. Link to post Share on other sites More sharing options...
sigtech Posted December 12, 2015 Author Share Posted December 12, 2015 Hello James, thanks for that useful reply - I have checked the info you gave me out and all is correct - the slave point - motors work correctly on their own, replicating the movement of the surface mounted motors - I should have mentioned that the fault has only occurred since adding the circuit for the leds - so the problem seems to be in the 12vdc circuit, - think I will be resorting to disconnections and chasing the problem with the multimeter.... Regards SIGTECH (Steve). Link to post Share on other sites More sharing options...
sigtech Posted December 13, 2015 Author Share Posted December 13, 2015 Have now checked through the led circuit, blowing up 3 12v led's in the process!!! Resoldering the 12v dc positive common feed, and also the common negative for the 16vac, I have discovered that I have 14.3v dc on it when the appropriate led is energised by point selection, - but simultaneously 7.3v ac - which is I assume is the cause of the problem - disconnecting the common ac return at the point motors has no effect - the ac voltage is still present, I am assuming it is being picked up on the Seep pm1's, from the point operation circuit. Would fitting a diode on each of the positive wires from the indication contacts to the led's to block the AC be a workaround?? Regards SIGTECH (Steve). Link to post Share on other sites More sharing options...
sigtech Posted December 14, 2015 Author Share Posted December 14, 2015 Just realized that I have written a load of nonsense, and that a diode will only make the ac half-wave, not block it , also wondering if the problem is more a case of overvoltage- i.e 14.3 v rather than 12v...? oh well, out with the multimeter again after dinner..!! Regards SIGTECH(Steve). Link to post Share on other sites More sharing options...
terrysoham Posted December 14, 2015 Share Posted December 14, 2015 You have used resistors in the LED circuit haven't you? For 12v dc try using a 1k ohm resistor for a higher voltage - 13.2 v try 1.25k ohm. Regards Link to post Share on other sites More sharing options...
sigtech Posted December 14, 2015 Author Share Posted December 14, 2015 Hello Terry, er nope... ( facepalm....).. I didn't realize I'd need to use one with the led's being 12v, but obviously I do!! Never used led's before, I normally use small conventional lamps... o.k - I see a quick trip to Maplins is needed tomorrow. Supply voltage is 14.3vdc . online resistor value calculator recommends 560 ohms.? Thanks for the 'heads up' on that, maybe that is the real problem after all and it's not my wiring at fault? Regards SIGTECH (Steve) Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted December 15, 2015 RMweb Premium Share Posted December 15, 2015 You have used resistors in the LED circuit haven't you? For 12v dc try using a 1k ohm resistor for a higher voltage - 13.2 v try 1.25k ohm. Regards The original poster did say he was using 12Volt LED's, but I agree, it sounds more like they are standard LED's. As for the 7.3 volts AC, I suspect that he'd be better off using a regulated DC power source, rather than an unregulated one. I'm guessing that the existing source is the uncontrolled supply from an old controller, where there could be all sorts of spurious voltages floating around. Link to post Share on other sites More sharing options...
terrysoham Posted December 15, 2015 Share Posted December 15, 2015 Steve, Just to clarify....are the LEDs supposed to operate from 12v DC? In which case they will have a built in resistor because LEDs need about 3v DC to operate - anymore than that and they go very bright and then die!! Have you tried lighting one just from a 12v DC supply? Remember positive wire to the longest leg of the LED. If they have built in resistors they should work straightway and, in which case, I am afraid that the problem does lies with your circuit. Let me know either way and I will help you sort it out. Regards Link to post Share on other sites More sharing options...
sigtech Posted December 15, 2015 Author Share Posted December 15, 2015 Hello again Terry- the led's are rated at 12vdc from Maplins, however the (uncontrolled) dc output on the gaugemaster , which goes to a 12vdc (uncontrolled) terminal block is actually supplying 14.3vdc, this is used to power a couple of old Hornby colourlight signals, a Heljan turntable, and ( eventually) leds in buildings and platform/yard lighting on the layout. I have just purchased some 620 ohm resistors to wire in series, will let you know if that does any good. Regards SIGTECH(Steve) Link to post Share on other sites More sharing options...
terrysoham Posted December 15, 2015 Share Posted December 15, 2015 Steve, The additional voltage shouldn't, in itself, be causing the blown LEDs. You say that the LEDs are rated at 12v DC which would imply that they are intended to operate from 12v DC without any additional resistor. However I would still suggest that you insert a resistor into the circuit - it won't do any harm. The resistor can go either side of the LED. Only power up one LED. If it works then great. If it doesn't work then come back to me and we will work together to resolve the problem. Regards Link to post Share on other sites More sharing options...
Brian Posted December 15, 2015 Share Posted December 15, 2015 Do you have the Maplin part number for the LEDs? IMO you would have made life far simpler in using these micro switches from Maplin, mounted opposite to the point motor and their lever worked by the points moving stretcher bar. http://www.maplin.co.uk/p/sub-miniature-lever-microswitch-gw67x Via their contact feed the LEDs. No additional loading placed on the point operation circuit and its power supply then! Link to post Share on other sites More sharing options...
sigtech Posted December 15, 2015 Author Share Posted December 15, 2015 Hello again Terry, have fitted one of the 620 ohm resistors in circuit, and it seems to work....... Now fitted all six, and again it seems to work (led's are outside panel at the moment, just testing out the switching) ! The leds are Maplin part numbers : CJ66 3mm 12vHE RED LED. : CJ67 3mm 12V GREEN LED. They are mounted in part number : N87AX 3mm Recessed Black Holders. Will let you know how it goes when I try to mount them inside the panel... Regards SIGTECH (Steve) Link to post Share on other sites More sharing options...
terrysoham Posted December 15, 2015 Share Posted December 15, 2015 Hi Steve, Just looked up your part number for the red LED. This is said to have the resistor built in so your circuit should have worked from the start with your 12v DC supply. Before you mount the LEDs in the control panel please remove one of the 620 ohm resistors, does the LED still work? If so then I suggest that you remove all of the 620 ohm resistors. If it blows the LED then reinsert the resistor. Again, before mounting them in the panel does moving the SEEP solenoid, switch the LEDs from red to green? If so, then mount the LEDs in the panel. If you mount the LEDs in the panel and then have a reoccurrence of the problem let me know. Regards Link to post Share on other sites More sharing options...
sigtech Posted December 16, 2015 Author Share Posted December 16, 2015 Hello Brian - I agree that in hindsight your method of arranging for the indication of the points is far easier, and less problematic, I should have looked at your site first really, as its bookmarked on my favourites... - the only reason I did it this way is because I already had the point motors, and was looking for a way of utilizing them....as I mentioned this is a retrofit job, and was not in the original scheme of things!! Regards SIGTECH (Steve). Link to post Share on other sites More sharing options...
sigtech Posted December 17, 2015 Author Share Posted December 17, 2015 Success...!!! Well we finally have working point indications on the three sets in the hidden sidings, (red for reverse and green for normal). This is indeed progress... I have updated my blog with the photos, also confirmed that the other part of this retrofit project - the optical detector ( from Blocksignalling. ) is operating correctly, thus enabling me to run the layout on my own. Thanks to Terry of Ely and District MRC for his input into the problems that occurred. Going to have a glass or two of wine now to celebrate!! Regards, SIGTECH (Steve). Link to post Share on other sites More sharing options...
terrysoham Posted December 18, 2015 Share Posted December 18, 2015 Steve, Well done. Very pleased that I could help. A good result! Regards Link to post Share on other sites More sharing options...
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