Fitting Wassel negative earth regulator

[Pauljhonley]

I'm trying to replace my mechanical regulator with a Wassel 10221 neg earth regulator.
My bike is a 1939 James K8 250cc.
I just cannot fathom out the wiring instruction wondered if anyone can help me.
Ive attached the instructions.

On the first page the instructions tell you to disconnect the field coil wire marked 1 and move it to the D terminal. Then to disconnect wire marked 2 from the earth screw and connect it to the F terminal.
Am I right in assuming these are internal Dynamo wires (See page1)

Then on Page 2 Diagram 2 it shows the yellow wire connecting to D terminal which connects to positive in the Dynamo.
The green wire is shown connecting to F terminal and then connecting to the D terminal but connecting to anything on the Dynamo.
Then finally the diagram shows the negative in the Dynamo connecting to the black wire.

Can anybody help me untangle this.
Paul

[chaterlea25]

Hi Paul,
Agreed its a bit confusing the way its shown
in diagram 2 neg earth they do not include a reasonable field winding symbol only a little square with F inside it
They use the same symbol for terminals ??

So
Connect one end of the field winding to D terminal also goes to positive brush
The other field winding goes to the F terminal
The negative brush is connected to the dynamo body
Test for correct rotation by
Connect a wire from the F terminal to the dynamo body, and then to a battery negative
Connect a wire from the D terminal to the battery positive
The dynamo should run as a motor in the same direction as it is driven on the bike
If it motors in the wrong direction swop over the field winding connections
This test should be enough to polarise the dynanmo

John

[Pauljhonley]

Thanks for your comprehensive reply John

I think I understand but its still a bit muddy.
Am I correct in my own words as below

Connections inside the Dynamo
According to the first page I need to change the field coil connections by connecting the positive field connection to Terminal D
Terminal D should already have a connection to the positive brush
The other field coil wire (-ve) is moved to Terminal F
The negative brush is connected to the dynamo body

In Diagram 2
I presume therefore that the Dynamo when rotating will send a voltage to the Field Coil through the wire connecting Terminal D with Terminal F. If this is the case how is the charge being regulated?
 
Paul

[chaterlea25]

Hi Paul,

Connections inside the Dynamo
According to the first page I need to change the field coil connections by connecting the positive field connection to Terminal D
Terminal D should already have a connection to the positive brush
The other field coil wire (-ve) is moved to Terminal F
The negative brush is connected to the dynamo body

Yes correct 

There are two ways that the field current is switched on and off to achieve regulation
Lucas and some others have one end of the field coil earthed, and "feed" the field coil from the battery live

Bosch and some American regulators and the Wassel  fix one end of the field to the live side of the battery/dynamo
and the regulator switches the connection to earth (chassis, or battery neg in your case)
JG conversion regulators also work like this
This setup makes polarising the field coil a bit more awkward,
You need to earth the F connection (-), Lift the live dynamo brush from the commutator (or disconnect the Field coil positive end and take a wire from the battery positive and spark it to the end of the field coil (+)

Current to the field is not "regulated" in a variable way simply switched on and off as the voltage falls and rises to the setting parameters of the regulator

John

[Pauljhonley]

Hi John
Just one last question.
In diagram 2 it shows that the terminals D and F are connected together.
Does this not create a short  since the F is connected to the -ve field coil wire and the D is connected to the +be Dynamo brush and to the +ve field coil wire.

Thanks so much I would never have figured all this out.

Paul

[chaterlea25]

Hi Paul
As I tried to explain the problem lies with the idiot who did the drawing 
It shows two little square boxes, one with D inside, this is a terminal on the dynamo
the box with F inside it represents the field coil
So one side of the field coil is connected to the D terminal ( the + brush and the yellow wire to the regulator also attach to D)
The other field coil wire goes straight to the F terminal where the green wire to the regulator also connects

Take a pen and draw a spiral across the F inside the box from one wire to the other, to represent the field coil

John

[iansoady]

As John says, those diagrams are crazy. Especially as the first ones seem to show a 3 brush dynamo....

Assuming you have a conventional Lucas dynamo, forget mucking about with internal connections - unless you need to change the rotation direction in which case come back.

It looks to me as though you just connect it in the same way as an original regulator would be - ie green to the field connection on the dynamo (simple way to remember - green fields!) and yellow to the D terminal. Ignore the connection that is shown to the dynamo earth - just connect the black lead from the regulator to the normal earth*. And connect the red as shown.


*Actually, I am a bit pernickety about earths so usually take an earth lead from a convenient point on the dynamo - eg the fixing strap - to a common earthing point.

[Pauljhonley]

John
thanks again and now I understand the diagram and can progress.


Ian
if that's the case it would make life a lot easier.
It is the original Dynamo from the bike which I had reconditioned. I told the firm in Sheffield who did the reconditioning what the rotation direction is.
So I guess there should be no reason to change it.

Have you experience of making the direct connections without internally changing the wires in the dynamo.
Paul

[chaterlea25]

Hi Ian and Paul
The connections required for the wassel are not standard Lucas
so need to be changed as explained earlier

John

[Pauljhonley]

Ill take look in the Dynamo
Thankyou fot your help
Paul 🤔

[iansoady]

Hi John.

Yes, you're right. It looks as though the regulator controls the earth side of the field rather than the live, which is how the resistor in the old 3 brush setup worked. Why they would do it this way god only knows as the conventional 2 brush Lucas is by far the most common, with the live side of the field being controlled by the regulator.

I fitted a Wassell regulator to an A10 a few years ago and I'm sure it was just plug and play which is probably misleading me. Apologies to Paul if I've misled you......to

[chaterlea25]

Hi Ian,
That's the Bosch and Autolite way of doing things 

John