How to test a 6V dynamo and source for voltage regulator?

[rusty...@comcast.net]

Hey group,

I am trying to make some progress on my Falcolino project (rough Falcone that will be a Dondolino clone) and I have a few electrical questions.  Is there a way to safely test a 6V dynamo on a bench with a lathe or drill to drive it without wiring a voltage regulator into the system?  I don't currently have a regulator and I don't want to risk damaging my dynamo.  Does anyone have a recommended source for a 6V regulator that will work on a Falcone?  Has anyone had luck with replacing the mechanical regulator with an electronic regulator?  If so, can you send the model and source?

Thanks!

-Jeff Buick

-Detroit, MI

[Bill Irwin]

Hi Jeff

Marelli and Bosch dynamos are wired differently to Lucas ones.  Both types will motor on a battery if they are in good working order and usually that’s sufficient to prove that the dynamo will produce a charge.

For Marelli and Bosch:

Connect the DF (Field) terminal to the dynamo body.  Connect battery + to the D+ terminal and battery – to the dynamo body.  The dynamo should spin in the direction of it’s normal rotation.

For Lucas:

Connect the DF (Field) terminal to the D+ terminal.  Connect battery + to the D+ terminal and battery – to the dynamo body.  The dynamo should spin in the direction of it’s normal rotation.

Podtronics do a solid state regulator for 6v Lucas type Dynamos but they won’t work with a Marelli unless you change the way the field coil is wired.  Lucas works with one end of the field coil earthed and the other to the regulator.  To obtain a higher output the regulator connects the field to the D+ dynamo output.  On Marelli and Bosch it works the other way round.  One end of the field coil is connected permanently to D+ and the regulator connects the other end to earth to obtain more volts.  

I used a DVR2 regulator from dynamoregulators.com after wiring my Marelli like a Lucas dynamo however I later read in the fine print that the resistance of the field coil must be at least 2.5ohms.  On the Marelli it is only 2.2.  The result was a fried regulator and armature.  Best to copy a system that has proven to work with the Marelli or stick with the old 6v electro mechanical regulator.

I’m currently using a setup using a Bosch RE55 regulator and external diode recommended by an electrician friend on my 6v Marelli converted to Lucas configuration.  I’ll let the group know details after I’m happy with it.  It is charging at 13.75v from my 6v dynamo.

Cheers Bill

From: <guzzi-...@googlegroups.com> on behalf of "rusty...@comcast.net" <rusty...@comcast.net>
Reply-To: "guzzi-...@googlegroups.com" <guzzi-...@googlegroups.com>
Date: Tuesday, 13 October 2015 3:07 pm13
To: Guzzi Singles <guzzi-...@googlegroups.com>
Subject: [guzzi-singles] How to test a 6V dynamo and source for voltage regulator?

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[rusty...@comcast.net]

Hi Bill,

Thanks for the reply!  Great info!  I will follow the method to test my dynamo in the next couple of days.  Please keep the list posted on how your conversion goes on your Marelli dynamo, it sounds like an interesting option.

Thanks!

-Jeff Buick

[richard...@hotmail.co.uk]

Hi Bill,
That is a nice way to test the dynamo. I recently bought an Airone and it needs a heap of work. I removed the dynamo to see if it was working, and as soon as I put a current through it, it started spinning. So I guess from what you say, that means it must be good.
However, I now have a question. How do I wire it up so that it has current for the magnet, but isn't trying to turn itself when the engine is idle ? Surely this will cook the dynamo ? Or am I missing something ?

[Bill Irwin]

Hi Richard

That¹s the job of the regulator which incorporates a cut-out to keep the
battery disconnected until the dynamo is producing enough voltage to equal
or exceed the battery voltage.

Regards Bill

On 25/01/16, 4:44 AM25 , "guzzi-...@googlegroups.com on behalf of
richard...@hotmail.co.uk" <guzzi-...@googlegroups.com on behalf of

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[richard...@hotmail.co.uk]

I see, thanks. The bike didn't come with a separate regulator ( or a battery ). Do I assume that all that jiggery pokery under the black end cap is an integral regulator ?

[Bill Irwin]

Hi Richard

Earlier bikes had the regulator incorporated into the dynamo. My bikes
both have separate regulators so I have no experience of the early ones
but I¹m sure that there will be others on the group who have. I would
have expected the cutout to prevent motoring of the dynamo unless you
bypassed the cutout or forced it closed.

Cheers Bill




On 25/01/16, 8:45 PM25 , "guzzi-...@googlegroups.com on behalf of

richard...@hotmail.co.uk" <guzzi-...@googlegroups.com on behalf of
richard...@hotmail.co.uk> wrote:

[richard...@hotmail.co.uk]

Thanks again Bill,
I didn't bypass the cutout, but somebody has definitely been there before me. The two wires that run to the external terminal have both been replaced at some time, and held on with insulating tape. Not a pretty job. Maybe the previous owner rewired it differently.

[richard...@hotmail.co.uk]

Thanks again Bill,

I didn't bypass the cut-out, but somebody has obviously been inside this dynamo before me. The two wires that attach to the terminals have both been cut and replaced and reattached with insulating tape to the remains of the original wires. It is possible that they are not connected correctly.  It would be nice if I could find a wiring diagram for this dynamo, but I expect I am going to have to work it out for myself.