ohanlonmartin Posted January 2, 2016 Share Posted January 2, 2016 Hi, Hopefully this query is in the right section of RMweb..... What I need help with initially is the correct gauge of flex cable to be used to wire Seep point motors (PM1 type), I am reading/hearing that a gauge of 0.20mm-0.25mm is sufficient but a friend of mine is recommending a minimum of 0.50mm, I have had a recommendation in Hattons to use their 0.22mm multi coloured single core cables. I see 6 core alarm cable listed as being 0.20mm and am wondering if that would be ok for what I need, the six different coloured wires in the cable would be a great help to me in setting up my control panel where I intend to use the simple probe and stud system for points changing but also to install indicator lights for each point. If it is important to know, the longest distance from the transformer to the furthest points is approx. 10 metres. Link to post Share on other sites More sharing options...
Griffin Road Posted January 2, 2016 Share Posted January 2, 2016 Before all the rubbish starts - the 0.2/0.25 has worked fine for me in the past . 0.5 is a bit overkill . Mike b Link to post Share on other sites More sharing options...
mjkerr Posted January 2, 2016 Share Posted January 2, 2016 Thin wire is perfectly fine as it is only being used for a moment of chargeThere are times you may need to go even finer, but I would then include a fuse just in case the momentary switch fails and you may not be aware of it Link to post Share on other sites More sharing options...
Penlan Posted January 2, 2016 Share Posted January 2, 2016 Voltage drop over 10 metres for 0.2mm wire, assuming 18v DC and 1amp current = 0.0067v,I don't think there's a lot to worry about there. I've used 0.2mm multistrand for decades, no problems. Link to post Share on other sites More sharing options...
olivegreen Posted January 2, 2016 Share Posted January 2, 2016 Before all the rubbish starts - the 0.2/0.25 has worked fine for me in the past . 0.5 is a bit overkill . Mike b Me too, although many here and elsewhere have said the contrary. Thicker wire could not really be criticised, but for a pulse from a capacitor discharge circuit and with not-too-long lengths of cabling, is unlikely to be necessary. Edit: penlan beat me to it… and more technically eloquently (if you see what I mean) ! Link to post Share on other sites More sharing options...
Griffin Road Posted January 3, 2016 Share Posted January 3, 2016 Thin wire is perfectly fine as it is only being used for a moment of charge There are times you may need to go even finer, but I would then include a fuse just in case the momentary switch fails and you may not be aware of it I have never seen anyone fit a fuse before . Can you maybe explain where please ? Mike b Link to post Share on other sites More sharing options...
ohanlonmartin Posted January 3, 2016 Author Share Posted January 3, 2016 Thanks to all respondents so far, I will go for the 0.20mm flex cable so. Link to post Share on other sites More sharing options...
Gordon H Posted January 3, 2016 Share Posted January 3, 2016 Voltage drop over 10 metres for 0.2mm wire, assuming 18v DC and 1amp current = 0.0067v, I don't think there's a lot to worry about there. I've used 0.2mm multistrand for decades, no problems. Are the wire sizes quoted so far referring to cross sectional areas or diameters? Also, the round trip length is 20m, so that has to be factored in too. The resistance of 7/0.2 wire is typically 80 Ohms/km (i.e. 0.08 Ohms/m), so 20m of that would come to 1.6 Ohms. With a current of 1A, that would give a voltage drop of 1.6V, as seen at the motor, so considerably more than that quoted above, and a loss of nearly 10%. The power delivered varies with the square of the voltage, so assuming 18V to start with, that amounts to a power loss of about 20%. By comparison, 16/0.2 wire would drop less than half this voltage, and deliver more than 90% of the power. Personally, I tend to use a 24V supply for this kind of motor drive, which minimises the effect of such losses. Link to post Share on other sites More sharing options...
ohanlonmartin Posted January 11, 2016 Author Share Posted January 11, 2016 Hi, Having just completed a schematic drawing, which will lead to the making of a control panel, for the points on my layout I am having second thoughts on whether to use the probe and stud method or go for a toggle switch or push button system. What's exercising me is the number of points that are used as cross overs and the proximity of studs so close together on the control panel that it may be cleaner/simpler to fit either toggle switches or push buttons. Anyone got any advice on either or both systems and the types of switches or push buttons to use please? If I can also ask is there a simple and reliable way to wire both points in a cross over so that one switch or push button will change both points? Link to post Share on other sites More sharing options...
ohanlonmartin Posted January 12, 2016 Author Share Posted January 12, 2016 Anyone??? Link to post Share on other sites More sharing options...
Gordon H Posted January 13, 2016 Share Posted January 13, 2016 Personally, I prefer to use toggle switches as their setting can be used to indicate which way the points are set too - but you do need to use a suitable driver circuit to allow non-biased switches to be used in this way. Link to post Share on other sites More sharing options...
raymw Posted January 13, 2016 Share Posted January 13, 2016 Studs and probe cost far less than any switch, and will be less fragile, and far easier to build. Your diagram can be 'spread out' in the denser stud areas. Link to post Share on other sites More sharing options...
ohanlonmartin Posted January 13, 2016 Author Share Posted January 13, 2016 Thanks to Gordon and Ray, I intend to use indicator lights to show points direction settings so maybe the probe and stud method won't be a draw back in that case. Can anyone help with the idea of wiring one toggle switch or probe and stud to be used to change both points in a crossover, if that is doable a simple wiring drawing would be of great help please, my electrics knowledge is just about zero so please excuse the very basic questions. Link to post Share on other sites More sharing options...
Free At Last Posted January 13, 2016 Share Posted January 13, 2016 There are wiring diagrams on Brian Lamberts page that show two motors working from one switch http://www.brian-lambert.co.uk/Electrical.html#Motor Link to post Share on other sites More sharing options...
ohanlonmartin Posted January 14, 2016 Author Share Posted January 14, 2016 Thanks for that link, it looks like just what I need. Link to post Share on other sites More sharing options...
LNER4479 Posted January 14, 2016 Share Posted January 14, 2016 Using one stud (or switch) to fire two motors as part of a cross-over is quite straightforward (and more prototypical!) as I'm sure the wiring diagram shows. Make sure however that you've got a decent power supply / CDU combo as you're asking for twice as much electrical power in one pulse so you don't want to end up with only one point actually going across when you think both have fired. Ask me how I know this... Link to post Share on other sites More sharing options...
ohanlonmartin Posted January 14, 2016 Author Share Posted January 14, 2016 Thanks LNER, I sympathise with you on your learning curve errors, this has been an extremely steep one for me for many years, only for the good folks on this forum and other helpful people I would have thrown the towel in many a time. Link to post Share on other sites More sharing options...
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