RMweb Premium DavidLong Posted March 4, 2015 RMweb Premium Share Posted March 4, 2015 On my test rig I have a 2FS point with track leading to it and two short branches beyond it. I have set up a TT300 switch machine underneath. I tested on DC with power supplied to the track and a separate power supply connected to the switch machine. The switch rails moved correctly and, at the same time, switched the polarity of the crossing as proved by a loco running across it. I then connected it up to power from an NCE PowerCab, initially without the crossing switching set up and the point operated correctly from the PowerCab. However, when I connected the A and B terminals to the track ( I already had a wire going to the crossing V) the PowerCab went into a cycle of resetting itself and would have gone on doing it if I hadn't then cut the power. I have tried the usual methods of swapping wires around but all have the same result of PowerCab resetting. The DC test certainly proved that the internal switch mechanism was working. I had been a little worried that the small movement, around 0.5mm, with 2FS may cause a problem but it didn't. The diagram supplied with the TT300 shows the DCC power supply and the connections to the track separately but of course with DCC they are in fact one and the same thing. The PowerCab supplies power to the bus which would then supply power to the track and to the switch machine. I can't see any way that they can be separate. All in all rather baffling. Anyone got any suggestions or is it simply a malfunction of my particular machine? David Link to post Share on other sites More sharing options...
smokebox Posted March 4, 2015 Share Posted March 4, 2015 Have you tried turning the point motor through 180 degrees? Link to post Share on other sites More sharing options...
RMweb Premium DavidLong Posted March 4, 2015 Author RMweb Premium Share Posted March 4, 2015 Have you tried turning the point motor through 180 degrees? I don't understand why that would help. All the wiring connections would be going to the same places that they are now. I suspect it would just mean that the 'off' and 'on' commands from the PowerCab would be reversed or have I missed something? David Link to post Share on other sites More sharing options...
shibushe Posted March 4, 2015 Share Posted March 4, 2015 David. I have 12 TT300s. Except for the earlier models that had a software problem which was sorted I have had no trouble with them. Although I use DCC, my motors are operated via a switch panel. Fig 5. Now, if your wiring is correct for DCC. Fig 4. on the instruction sheet, then for the life of me I cant fathom your problem. Turning 180 wont make any difference. May be worth a call to the maker. DONT email them. Phone. Link to post Share on other sites More sharing options...
Only-Me Posted March 4, 2015 Share Posted March 4, 2015 Have you the standard cab, is it drawing too much power and resetting the unit? Do you use a cdc (not sure if relevant on 3300)! Link to post Share on other sites More sharing options...
smokebox Posted March 4, 2015 Share Posted March 4, 2015 I don't understand why that would help. All the wiring connections would be going to the same places that they are now. I suspect it would just mean that the 'off' and 'on' commands from the PowerCab would be reversed or have I missed something? David I think turning it reverses the polarity of the connection to the frog, so that instead of connecting the + rail to the frog, the - gets connected to the frog for the same routing. Worth giving it a go, I would think. Link to post Share on other sites More sharing options...
Vonzack Posted March 5, 2015 Share Posted March 5, 2015 Or you could leave everything as it is and reverse the sense of the motor by programming it. No need to turn the motor around. I had a duff TT300 that caused a constant short with DCC no matter what you did, maybe you've got something similar. I'd also check that the 0.5mm throw is adequate for the unit to polarity switch properly. Cheers, Mark. Link to post Share on other sites More sharing options...
RMweb Premium DavidLong Posted March 5, 2015 Author RMweb Premium Share Posted March 5, 2015 Or you could leave everything as it is and reverse the sense of the motor by programming it. No need to turn the motor around. I had a duff TT300 that caused a constant short with DCC no matter what you did, maybe you've got something similar. I'd also check that the 0.5mm throw is adequate for the unit to polarity switch properly. Cheers, Mark. Mark, I did wonder about reversing the sense but I'm still not sure that it is the root of the problem. The polarity switch didn't have any problem with changing the polarity of the crossing when in DC mode. The behaviour of the PowerCab when the track connections are in place seems to indicate a short of some description and maybe it is just a case of a faulty machine. It is slightly irritating that without those connections it works perfectly. For the sake of completeness I am attaching a photo of the set up. Excuse the Heath Robinson appearance but it is a test rig! The feed from the PowerCab comes in at top right. There are two copper strips which constitute the bus. Wires go from the feed to the bus which in turn have wires going up to the track. I have taken two wires directly to the power terminals on the TT300 although I have also tried them attached directly to the bus. Wires from the A and B terminals go to each part of the bus and a brown wire goes to the crossing vee. I did try taking two wires directly to the track as shown in the instructions but with no difference to the end result. As I said, using a PowerCab there is no difference between track power and power for any accessories which use that power so taking wires to the track rather than the bus is pretty pointless. David Link to post Share on other sites More sharing options...
RMweb Premium DavidLong Posted March 5, 2015 Author RMweb Premium Share Posted March 5, 2015 Have you the standard cab, is it drawing too much power and resetting the unit? Do you use a cdc (not sure if relevant on 3300)! It's a standard PowerCab and operates the machine perfectly. It is the polarity change with DCC that is the problem. Ok on DC. David Link to post Share on other sites More sharing options...
smokebox Posted March 5, 2015 Share Posted March 5, 2015 That looks like a bridge rectifier over on the RHS of the picture, you have not mentioned that anywhere, what does it do? Keith Looks like a terminal block to me. Link to post Share on other sites More sharing options...
RMweb Premium DavidLong Posted March 5, 2015 Author RMweb Premium Share Posted March 5, 2015 Looks like a terminal block to me. And so it is! Wouldn't know a bridge rectifier from a jar of honey . . . David Link to post Share on other sites More sharing options...
shibushe Posted March 5, 2015 Share Posted March 5, 2015 David. Further to my post yesterday. Have had another look at the advanced options for the TT300. Again I can see nowt wrong with your wiring. All I can say, and repeat from my last post. Give Traintronics a call maybe the only way you will solve it. You have to remember that within the TT300 there miniature parts, could be a glitch inside. Link to post Share on other sites More sharing options...
Vonzack Posted March 6, 2015 Share Posted March 6, 2015 Hi David, Agree, your wiring looks fine. I'm sure this isn't the problem, but it might be worth a try swapping D1 and D2 around. Do you have another TT300 to test with? You could try to remove the TT300 from the board, send a throw or close command to it and stop the actuator by hand to see if this works. Cheers, Mark. Link to post Share on other sites More sharing options...
Grovenor Posted March 6, 2015 Share Posted March 6, 2015 Looks like a terminal block to me. Immediately after posting I enlarged the pic for a better look and realised that it is indeed a terminal block, and deleted my post before any reply had appeared! You really got in quick. Cheers Keith Link to post Share on other sites More sharing options...
RMweb Premium DavidLong Posted March 6, 2015 Author RMweb Premium Share Posted March 6, 2015 Hi David, Agree, your wiring looks fine. I'm sure this isn't the problem, but it might be worth a try swapping D1 and D2 around. Do you have another TT300 to test with? You could try to remove the TT300 from the board, send a throw or close command to it and stop the actuator by hand to see if this works. Cheers, Mark. Hi Mark, Tried the wire swapping in several combinations. No change! At present the TT300 has been removed and replaced with a digital Cobalt which seems to be performing OK. It's a bit more hassle due to my need to mount it horizontally because of low clearance on the layout that the set up is destined for. The upside is that the Cobalt only needs two wires to the bus and one to the crossing. This is the idea of the test rig to try to iron out any wrinkles before committing the idea to the layout. Thanks for your inputs. David Link to post Share on other sites More sharing options...
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