Seacommander Posted August 17, 2019 Share Posted August 17, 2019 I have a couple of stand alone layouts that I use with my Elite controller and Hornby 4 amp power supply. To simplify transferring both the controller and power supply from layout to layout I was wondering if the spare 15 volt 5 amp laptop power supply I have would be OK to use with the Elite. It would be convenient to have this permanently installed underneath the baseboard. The size and polarity of the connector is compatible with the Elite.Maybe one of the more electronic savvy members could advise me please. Link to comment Share on other sites More sharing options...
Rog RJ Posted August 18, 2019 Share Posted August 18, 2019 As long as the polarity of the power supply is correct, it will work. The problem is that if there is a fault or you accidentally exceed the 4 amps that the Elite is designed for you may damage the Elite due to excess current. Link to comment Share on other sites More sharing options...
2e0dtoeric Posted August 18, 2019 Share Posted August 18, 2019 Put a 4 amp fuse in the line, if you can find one! 😎 Link to comment Share on other sites More sharing options...
ColinB Posted August 18, 2019 Share Posted August 18, 2019 Having a 5 amp suplly rather than 4 amp is not an issue, the power regulator inside the Elite will sort that out. It wll normally have a regulater to regulate down to 5 volts or 3.3 volts for all the logic. Having not enough current is normally the big issue. The bigger issue is the polarity of the connector and the correct voltage. If these are correct, then I see no reason why you cannot use one. No need for a fuse, the laptop supply should have some current limit capacity. I use them all the time for lots of things, be wary of the really cheap ones from China. Link to comment Share on other sites More sharing options...
Seacommander Posted August 21, 2019 Author Share Posted August 21, 2019 Thanks everyone for your comments. I took the plunge and connected a Toshiba 15 volt 5 amp laptop supply to the Elite (after double checking the polarity of the plug and the DC voltage) and all is working well. Out of curiosity I connected the output of the Toshiba and Hornby (the 4 amp power supply) to an oscilloscope and discovered, not unexpectedly, that both supplies had an underlying somewhat noisy AC ripples, however, what did surprise me was that the peak to peak voltage for the Toshiba was around 0.5 volts but about 48-49 volts for the Hornby. I assume the current is negligible but just wonder is this typical? Link to comment Share on other sites More sharing options...
ColinB Posted August 21, 2019 Share Posted August 21, 2019 It sounds like the Hornby is an AC supply, whereas the Toshiba is a DC supply. It doesn't matter, the Elite should have a regulator that sorts it out. I am surprised, I thought the Elite power supply was DC, I will check mine next time I get the scope out. Anyway it works, and you shouldn't blow anything up, so that is good. A lot of the laptop power supplies are switched mode, that is how they make them so small, which is why the cheap ones from China can catch fire and are not as safe. I assume the Elite's is a conventional transformer, as the design is quite old. Link to comment Share on other sites More sharing options...
Chrissaf Posted August 22, 2019 Share Posted August 22, 2019 I can confirm that Hornby power supplies that feed the eLink, Elite and Select are 100% definitely supplies with 15 volt DC outputs that use 'switch mode' technology. So yes, there will be some element of ripple on the output, but this should be so low as to be only viewable on a scope trace..It may be (but I think this unlikely) that the switch mode power supply in the Hornby design needs a load attached before correct output regulation is observed. I assume that to measure the output of the 15 VDC power supply it had to be disconnected from the controller to access the pins on the DC connector, thus this observed 48-49 volt measurement was taken 'off load'..It is not clear, whether this unusual measurement was taken from the scope trace or a traditional multi-meter. If taken with a multi-meter, then I would suspect that first before jumping to conclusions about the power supply. Either way, given that the baseline output is 15 volts DC, then a 50 volt peak to peak swing would be going from +65 volts to -35 volts and would indicate some form of 'ringing' on the output. If these readings are absolutely genuine and observed with a load attached then I would treat the Hornby power supply as being faulty. Link to comment Share on other sites More sharing options...
96RAF Posted August 22, 2019 Share Posted August 22, 2019 You should also remember that Hornby uses an odd size DC plug on their DCC power supplies, as pointed out on the forum previously. Link to comment Share on other sites More sharing options...
Chrissaf Posted August 22, 2019 Share Posted August 22, 2019 As Rob says, an uncommon connector..The DC Coax connector power plug used on Hornby 'Digital Controller' power supplies is 6.3mm / 3.0mm Link to comment Share on other sites More sharing options...
Seacommander Posted August 22, 2019 Author Share Posted August 22, 2019 The measurements were made off load as Chrisaff aludes to and were only taken for interest as I have no reason to suspect any problems with the Hornby PSU - it works faultlessly. I used a multimeter to confirm 15 volts dc - which was spot on. My AC ripple measurements were made using a scope but again as Chrisaff suggests I merely attributed the high peak to peak as being a result of no load on the output. I suspect as soon as a load is applied the peak will fall right off.Again as a matter of interest the plug fitted as standard on the Toshiba PSU is the same size as the Hornby so I was lucky there. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.