E3L Dynamo conversion to 12volt failed

[ybocalandro]

Please, I need some help with my Lucas E3L Dynamo. I rewound it to 12volt and it wasn't work.
I followed every step as trev said in a forum and and the output voltage was very low
I really appreciate any answer or contact to trevinoz     

[RichardL]

Hello,

Welcome to the forum. I'm not the one to give you advice on your dynamo rewind, but I'm quite certain Trev, Groily and a few others will soon be online with the help you need. I believe you are our first Cuban member. To me, this is great, and a testimony to our fearless leader's (Erling's) original idea. I'm wondering, have BSAs been kept in working order in some large numbers there in Cuba, much like old Chevys and Fords?

Regards,

Richard L.

[groily]

Don't know about BSAs on Cuba, but I know there are some nice Matchlesses there, as there was a great article a year or so back in the owners' club mag, the Jampot. A real tribute to the owners that they ran at all, let alone looking pretty decent. Made me realise how lucky we are in some other countries as far as parts are concerned!
On the dynamo conversion, best let trev comment as I can't off-hand recall what his preferred route was, from the options available, and don't want to cause confusion. Very happy to add 2 cents' worth as the thread goes along though as I'm sure will many others.

[ybocalandro]

thanks for your answers, and you are right, is really really difficult to keep my BSA cause we haven't spare parts and the way to get its, so we have to improvise every day, in my case my A10 isn't an antique, it is my means of transportation, that's the reason of my hurry to put my dynamo back to work       

[trevinoz]

Hi ybocalandro, [that's a mouth full]

If you have wound a new field coil and it is OK for continuity and is not earthed internally to the pole shoe, that part should be right.
When you rewound the armature, did you connect the coil ends to the correct commutator segments?
Did you motor test the generator after you reassembled it?
If so, did it rotate in the correct direction?
Did you test the armature for short circuit to earth? This can happen due to shorted commutator segments or windings.
It's a good idea to drive the generator with the "D" & "F" terminals joined, connect a voltmeter between the terminals and earth and see what you get.
Trev.

[ybocalandro]

Hi Trev bocalandro is my surname, Is read your post about your E3L specifications and i rewound the armature with 20 turns per coil of 0.7 wire and 450 turns of two wires of 0.3mm in parallel cause i haven't 0.6, the resistance was the same aprox 5.6ohms
I did a bank test with a drill about 2000rpm and i got 8volt and 25A with a 12v 7A battery

I reassembled it and it rotated in the correct direction and I'm sure is not earthed because there is not continuity between the commutator and the armature.

Trev i was trying to ask someone how many segment have the commutator, mine is 24, it is right?           

[trevinoz]

What is your first name? Much easier that way.

Commutator has 12 segments but each segment is actually 2 pieces in parallel.
If you haven't connected the armature windings to the correct segments, say one away, you will get a low voltage output.
Are you sure that you got 25Amps output? That seems extremely high!
You should be able to exceed 20V when testing as I described.

   Trev.

[ybocalandro]

Please send me a email to ireinoso@infomed.sld.cu to send you picts of my dynamo
and then you will give me your considerations
thanks a lot

That's my home email I'm working right now

[HondaPete]

Hi  I am a new member to this forum and very interested in the dynamo rewind to 12v possibilities. I have rewound an old cooked armature with more turns and thinner wire as one of the older posts but I think I have connected the windings to the commutator incorrectly as I get next to nothing out. I tried to see where they were before I stripped it but it was too burnt to get an accurate assesment. Can anyone explain the connection of the leads from the winding to the commutator that is easy to understand - please   
Many thanks in advance for any help  Peter

[bsa-bill]

Brave man HondaPete or do you have skills and knowledge in the generator field (pun intended)

As your new to the forum maybe you don't know about flashing the dynamo search for "Flashing" or "dynamo polarity" and you should get some info

meanwhile this from forum member Sparx
 The field coil pole piece retains a small magnetic field when the dynamo is at rest just like those nails did when you made electromagnets as a kid. It's called the "residual flux". Depending on if the earth polarity is positive or negative it's either north/south or south/north.
  The dynamo uses this residual magnetic flux to build up the field current when starting from rest. If the flux polarity is wrong the voltage on the "D" lead will be the wrong polarity. The cut-out contacts in the control box will still switch in, but will probably be destroyed by what is more or less a short circuit current flow.
  To prevent that from happening you quite simply disconnect the "F" terminal on the dynamo and feed the field coil(s) directly from the battery for a second or so before starting the machine after changing or reconditioning the dynamo.

  You don't get quite the same problem with a solid state regulator, the diode that isolates the dynamo from the battery when the dynamo output is below battery voltage won't allow the short circuit current to flow, but because the switching circuits are connected to the dynamo output they see a reverse polarity and can get fried.
  I'd best stop there. My eyes are starting to glaze over.....
 

[HondaPete]

Thanks for the info, I had re-magnetised the field yoke but to no avail. I know a fair bit about windings but little about dynamo armatures and I think I have screwed up the connections to the commutator.
Still its all a learning expierience, nothing vetured nothing gained.

Peter

[trevinoz]

Pete,
            If you know a bit about winding, try the following.
The pitch is 1-6.
The start of a coil is connected to the comm segment directly forward of slot 6 and the finish is connected to the next one to the right, coil being wound clockwise.
The start of the next coil is connected to the finish of the previous one, therefore the coil 2-7 starts from the segment in front of slot 7 where the finish of coil 1-6 will be connected.
Work your way around the armature and the final coil's finish will connect with the start of the first coil.
An easy way to wind is to do it it one go without cutting the wire between coils and leaving a loop at the end of each coil long enough to reach the comm.
That way all you have to do is connect each loop to the segment one to the right of the finish end slot.
This will not work if you wind, like I do, a "balanced winding" but will work for the original method.
Clear as mud?

  Good luck.
                      Trev.

[HondaPete]

Many Thanks Trev I will have a look at what I did and see where I went wrong

Peter

[HondaPete]

Hi Trev  I have removed the windings as they were wrong and sketched out what I think you mean in the attached pic.
Also what is the "balanced winding" method ?
 Peter

[trevinoz]

Peter,
           Your diagram looks good to me.
To wind "balanced", you wind the first coil 1-6, second 6-11, third 11-4 etc.
This gives a better weight distribution of copper around the armature compared to the original "progressive' winding.
However, you can't wind this way without cutting the conductor at the end of each coil.
To avoid confusion between "starts" and "finishes", I tie a knot in the end of each "finish".
Back to work, Peter!

   Trev.