Internal Dynamo Wiring

[Steve Jones]

I have a Lucas dynamo on one of my cars that has been converted to 2 brush, 12 volt operation. It charges through an electronic regulator and rectifier and has been giving trouble. Despite working on it off and on all week, I can't make it work properly despite changing every component. 

I also have another 2 brush, 12 volt Lucas dynamo on another car that charges through a Lucas RB106 regulator/cut out (Morris Minor type). This has worked without any issues for over 10 years with no attention of any kind. 

I have  a new, old stock, Lucas RB106 cut out/regulator and I'm now minded to use this on the car where the electronic kit is giving trouble. I am aware that when these 2 brush, 12 volt conversions are done, the dynamo is wired differently, internally, depending whether it is to be used with an electronic regulator or a mechanical regulator. Electronic uses a 'Continental' wiring layout, mechanical an 'English, Lucas' layout. 

My problem is that I am a complete electrical/electronic ignoramus and I need specific, easy to follow instructions as to how to change the 'Continental' wiring in the dynamo to the 'English, Lucas' layout. Any advice gratefully received particularly if it doesn't use big words that I won't understand!

Thanks in advance, 

Steve

[Robert Leigh]

I have a Lucas dynamo on one of my cars that has been converted to 2 brush, 12 volt operation. It charges through an electronic regulator and rectifier and has been giving trouble. Despite working on it off and on all week, I can't make it work properly despite changing every component. 

I also have another 2 brush, 12 volt Lucas dynamo on another car that charges through a Lucas RB106 regulator/cut out (Morris Minor type). This has worked without any issues for over 10 years with no attention of any kind. 

I have  a new, old stock, Lucas RB106 cut out/regulator and I'm now minded to use this on the car where the electronic kit is giving trouble. I am aware that when these 2 brush, 12 volt conversions are done, the dynamo is wired differently, internally, depending whether it is to be used with an electronic regulator or a mechanical regulator. Electronic uses a 'Continental' wiring layout, mechanical an 'English, Lucas' layout. 

My problem is that I am a complete electrical/electronic ignoramus and I need specific, easy to follow instructions as to how to change the 'Continental' wiring in the dynamo to the 'English, Lucas' layout. Any advice gratefully received particularly if it doesn't use big words that I won't understand!

Thanks in advance, 

Steve

I am not familiar with using the RB106 with an Austin Seven dynamo, but I do have wiring details for the Dave Lindsley electronic regulator and for the AO electronic regulator. I do not recommend the AO system for an Austin Seven because it is arranged so that it does not start charging until the dynamo is up to twice the normal cut-in speed.
Robert Leigh

[Charles P]

Running the engine too slowly to charge isn't a problem that will trouble Steve

[Steve Jones]

Quite Charles!!

Thanks for your input Robert but the regulator is not, really, relevant to my question. I know that there are two alternatives for wiring a dynamo internally and I'm trying to find out what those two alternatives are.

I have made some progress in relation to that. On Dave Armstrong's excellent Spedex site there's a basic diagram that I suspect answers my question - see http://myweb.tiscali.co.uk/speedex/index...ge1173.htm. This indicates that one system has the dynamo field connected to earth (I believe this is the Lucas/English system). The second has the dynamo field connected to D on the dynamo (I believe this is the Continental system given that a Lucas A7 dynamo so wired would have two wires rather than on coming out of the dynamo to the D terminal). My dynamo certainly has the additional wire running to D so I think I've found what I'm after but confirmation that I have would be very gratefully received.

Steve

[Terrytuned]

Steve the Cornwall A7 club site have some excellent articles on dynamo and regulator circuits.
Terry.

[Steve Jones]

Thanks Terry. I'd read it through earlier in the week but it doesn't answer my question. It also uses some 'big electrical words' that I don't understand!!

However, after messing about with the thing for nearly a week and a half, I think I've cracked it. The diagram on the Speedex web site that I referred to above explains it exactly. In the English/Lucas system, the field is connected to earth. In the Continental system, the field is connected to D on the dynamo. To change from one system to the other takes no more than moving the field lead. I've spent the day swapping components over from a working car to a non-working car and I've worked out that the initial problem was caused by a failing armature in the dynamo. I did have a second, spare, 12v 2 brush dynamo that had never been used but substituting that caused the electronic gubbings to throw a fit when I tried it earlier in the week. It's only today that I've realised that the cause of that was that the 'new' dynamo had been wired for positive earth rather than negative. Easy when you know. If you set it up on the bench as a motor, it spins in the wrong direction!! I've now got a working electronic system again and also now know how to change to a mechanical regulator if I wish.

Steve