pelistry2 Posted February 20, 2011 Share Posted February 20, 2011 I have a dcc layout but am trying to operate point motors with switches on a separate circuit, I have fitted a capacitor discharge unit but point motor operation is sporadic! I am using an old Hornby control unit taking power from the 16v outlet. What am I doing wrong please Link to post Share on other sites More sharing options...
Kenton Posted February 20, 2011 Share Posted February 20, 2011 Are you giving sufficient time for the capacitor to recharge. Probably only a second. Link to post Share on other sites More sharing options...
pelistry2 Posted February 20, 2011 Author Share Posted February 20, 2011 Are you giving sufficient time for the capacitor to recharge. Probably only a second. I think I am. I have waited for it to recharge and sometimes it will work, but most times the points will not change Link to post Share on other sites More sharing options...
noiseboy72 Posted February 20, 2011 Share Posted February 20, 2011 Probably need a bit more info... Is it always the same points that don't throw ir is it random ? Is the 16V supply AC or DC ? What make is the CDU? My guess would be poorly lined up point motors or too thin cable to them causing voltage drop. I only have 9 points, some fired from an LS150 with AC and some from a MERG CDU based deocder. Both throw fine 99% of the time. I have one point that needs a tweak once on a while and a PECO point mounted switch that does not always switch with the point in cold weather. In my experience, most problems are alignment based. Link to post Share on other sites More sharing options...
Dan6470 Posted February 20, 2011 Share Posted February 20, 2011 You may find that the old Hornby controller that you are using is outputting a 16v AC output and that your CDU may require a DC input in which case it wouldn't work properly. Check the spec of both units. Dan Link to post Share on other sites More sharing options...
Kenton Posted February 20, 2011 Share Posted February 20, 2011 Probably need a bit more info... In my experience, most problems are alignment based. I would agree with that wholeheartedly ... and that applies to all makes of point motor. Until you experience problems - too little care is taken in setting up the mid-point of the throw with the mid-point of the tie bar and ensuring that the travel of the throw is parallel with the tie bar. It would be nice to know the make of CDU and the motors. There are a few other options: for example is the hole in the baseboard big enough to accommodate the throw or has it filled up with ballast? : are the metal cores of the solenoids well lubricated? Have they rusted? (see Sticky Solenoid topic) : is the switch mechanism hindering the throw? Link to post Share on other sites More sharing options...
Brian Posted February 20, 2011 Share Posted February 20, 2011 Hi 99% of all operating problems can be down to these few things..... 1) Motor not correctly aligned with point. Especially important with below baseboard motors and even more so with surface mounting types from Hornby - R8243 and Peco - PL11. They can be pulled down too tightly or are not in direct line with the moving tie bar. 2) Motor wiring too small. Use as a very minimum 16/0.2mm2 wire and a larger size is even better. 3) Power supply giving insufficient voltage and current (ac Volts and /or Amperage too low) Absolute minimum is 16 volts ac at 1.0Amp. 4) Trying to route set too many points at once even when a CDU is used. 5) Point itself is binding somewhere. Check for it not being pulled down to tightly or unevenly and that no ballast or adhesive has got into the mechanism. Check operation both ways with the motor removed and by finger. It should be free and easily moved over and back. Link to post Share on other sites More sharing options...
Free At Last Posted February 20, 2011 Share Posted February 20, 2011 You haven't mentioned what switches you are using, but Hornby passing contact switches don't work well with a CDU. Link to post Share on other sites More sharing options...
pelistry2 Posted February 21, 2011 Author Share Posted February 21, 2011 many thanks for your replies. I am using new Hornby R8014 point motors with new Hornby points. The CDU was purchased new on e'bay with no makers name but manufactured in UK. Spec. is: recommended supply 12v - 16v AC or DC Max current del. 5A Max range 9v - 24v The switches are mini toggle..centre off type I have 11 sets of points, but all operate independently. The problem is still with me this morning!!! Link to post Share on other sites More sharing options...
Dan6470 Posted February 21, 2011 Share Posted February 21, 2011 but point motor operation is sporadic! Is that the case with all of your points or will some points operate, perhaps in one direction only? Thing is from the info that you have provided it is difficult to see whether the problem is mechanical or electrical. If some points work then I would assume that the CDU is operational and that the problem is likely to be either mechanical due to alignment issues or electrical due to wiring issues both suggested by noiseboy72 and Brian. If you can confirm if some, or any, points do operate all of the time ie 100% switching in both directions, or all of the time in one direction only! It would perhaps be worthwhile for you to check/test each point in turn to see if they will switch in either direction, note your results and advise. Test each point several times! Dan Link to post Share on other sites More sharing options...
Kenton Posted February 21, 2011 Share Posted February 21, 2011 Are the connections soldered - to switches and motors. The intermittent nature of the problem (sometimes works on the same point sometimes doesn't - but no total failure or pattern) it could be as simple as a "dry" soldered joint. I assume the centre off switches are being rapidly returned to the off position - leaving them on for any period of time will damage the point motor - even with a CDU in place. A passing contact switch is a better approach to solenoid operation as the risks of leaving a switch in the "on" position is too great. Link to post Share on other sites More sharing options...
pelistry2 Posted February 21, 2011 Author Share Posted February 21, 2011 Some improvement today . I have checked all connections and ensured all baseboard holes are large enough. The situation now is 3 point motors only work in one direction. Also I have changed 2 of the switches to eliminate them as a possible cause. The CDU would appear to be working ok. Plus I have fitted to new sets of points as 2 appeared to be stiff. All the switches seem ok. Could the problem be voltage drop? Although there are no long runs involved and the point motor furthest away is ok. Link to post Share on other sites More sharing options...
pelistry2 Posted February 21, 2011 Author Share Posted February 21, 2011 all joints are soldered Are the connections soldered - to switches and motors. The intermittent nature of the problem (sometimes works on the same point sometimes doesn't - but no total failure or pattern) it could be as simple as a "dry" soldered joint. I assume the centre off switches are being rapidly returned to the off position - leaving them on for any period of time will damage the point motor - even with a CDU in place. A passing contact switch is a better approach to solenoid operation as the risks of leaving a switch in the "on" position is too great. Link to post Share on other sites More sharing options...
RAF96 Posted February 21, 2011 Share Posted February 21, 2011 I had a problem with one particular surface mount Hornby motor and found it must have been wired wrong ex-works. I could either get this particular one to throw both ways OK but wrong for the selection made, or one way only when I reversed the + & - connections. In the end I had to switch the common with the + to get proper reaction both ways for the selections made. Note also that PECO and Hornby motors have different wiring codes and that aids confusion. Rob Link to post Share on other sites More sharing options...
Brian Posted February 21, 2011 Share Posted February 21, 2011 What size of wire is used throughout all the point wiring, including the wire to the switches from the CDU? Dont forget if two solenoids are being operated at once from one switch then the wire size needs increasing where they share the same feed and/or return wire. The very minimum wire size should be 16/0.2mm and anything larger is actually better. Avoid purchasing model shop wire that's often called 'Layout wire'. Most of this is 7/0.2mm and not really suitable for solenoid motor operation. A CDU will help prevent coil burn out, as once the CDUs capacitors have discharged only a few milliamps can flow into the coil with a switch remaining closed and the capacitors cannot commence to recharge until all switches are restored to their off positions. The use of (On)-Off-(On) spring to centre off switches have been used for years to control solenoid points, especially where a mimic panel is used. I myself used them, though I'm just converting to MERG Digital control of all my point motors via their Panel encoder and decoders around the layout. Carry out my 5 most popular causes check I published earlier, I'm sure one or a combination of them are the cause. Link to post Share on other sites More sharing options...
Kenton Posted February 21, 2011 Share Posted February 21, 2011 The use of (On)-Off-(On) spring to centre off switches have been used for years to control solenoid points, especially where a mimic panel is used. I myself used them, though I'm just converting to MERG Digital control of all my point motors via their Panel encoder and decoders around the layout. Yes, but the emphasis that must be made is spring the normal variety you end up with is you do not specify this is the latching type. So easy to switch and leave (On) burning out the coils or damaging the CDU. Suggested course of action. 1. Identify one point that is working perfect every time and one that is working intermittent. 2. If you can - without unsoldering anything and without moving the point s in any way - swap the point motors. 3. retest. Like all fault finding the solution has to be sought one logical step at a time. Starting with the cheapest and most obvious. I would not go buying new of anything and certainly not swapping many things at once. Let's try to rule out or in one thing at a time. If after performing the above the "intermittent fault" is transferred to the other point then the point motor seems most likely - you then replace it with a new one then test again... Link to post Share on other sites More sharing options...
pelistry2 Posted February 22, 2011 Author Share Posted February 22, 2011 Improvements now! I have gone through all the steps you have all mentioned and have had all point motors operating, although one is still sticking sometimes, this may be due to alignment and tomorrow I intend laying this set of points again. Many thanks to you all, as you have probably gathered this is my first attempt at a layout, but today for the first time I had a Class 37 with DCC sound running, brilliant! it makes it all worthwhile. Yes, but the emphasis that must be made is spring the normal variety you ebd up with is you do not specify this is the latching type. So easy to switch and leave (On) burning out the coils or damaging the CDU. Suggested course of action. 1. I dentify one point that is working perfect every time and one that is working intermittent. 2. If you can - without unsoldering anything and without moving the point s in any way - swap the point motors. 3. retest. Like all fault finding the solution has to be sought one logical step at a time. Starting with the cheapest and most obvious. I would not go buying new of anything and certainly not swapping many things at once. Let's try to rule out or in one thing at a time. If after performing the above the "intermittent fault" is transferred to the other point then the point motor seems most likely - you then replace it with a new one then test again... Link to post Share on other sites More sharing options...
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