Emmo Posted October 30, 2013 Share Posted October 30, 2013 Hi - Does anyone know if it is ok to use the Hornby R044 (Black) passing contact switch to operate H & M point motors via a CDU? I've heard somewhere that the Hornby switches don't work very well with CDUs due to the way they are wired, but the H & M motors have some sort of reversing mechanism making them suitable to use with these switches. I want to use the R044s as I can make up a bank of them to look like a miniature lever frame. If anyone has any of these, I would appreciate the dimensions of the footprint including the distance between mounting holes if possible please. And, subject to the result of my questioning above, if there are any you want to sell... Link to post Share on other sites More sharing options...
naugytrax Posted October 30, 2013 Share Posted October 30, 2013 The H&M point motors have a built-in single-pole double-throw switch (like SEEPs). This is often used to supply turnout frogs with the correct polarity, but can also be used to cut off the current supply to the appropriate solenoid coil as the points complete their travel. When they are wired like this, you don't need to use a momentary-contact switch and instead you can control the points using a simple SPDT switch like the one Hornby sells for color-light signals. But this doesn't provide a way to get around the unsuitability of the Hornby R.044 for CDU supplies, which is caused by its "fire both outputs during each throw" characteristic. Peco make momentary-contact switches for point motor control. These have different internal mechanisms from the Hornby ones, and so they can be used with CDUs. I believe they can be grouped in banks. Have you considered these? Link to post Share on other sites More sharing options...
Emmo Posted October 30, 2013 Author Share Posted October 30, 2013 Thanks for that. I have considered the Peco ones, but already have some of the Hornby's and was wondering of a work around so I can use them with my H&M motors already installed on the layout. I already use the built in switch on the H&M motors for frog polarity - can I use them as you describe as well as? If so, what wires go where - duh...? Link to post Share on other sites More sharing options...
naugytrax Posted October 30, 2013 Share Posted October 30, 2013 Sorry, there's no free lunch available here! If you want the H&M turnout motor to switch its own operating current in addition to switching the track current to the frog, you need to add a second SPDT switch. For this purpose, H&M used to make an auxiliary switch assembly which bolted directly on top of the built-in switch. Your existing Hornby R.044 switches can't be used in this arrangement. You would have to replace them with R.046 switches. Link to post Share on other sites More sharing options...
Emmo Posted October 30, 2013 Author Share Posted October 30, 2013 In that case I have some R044's for sale then! Link to post Share on other sites More sharing options...
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