Topolino voltage regulator

[flyturner]

anyone used a solid state unit in a Topolino? Can I use one from a 500? Struggling to find original one
Cheers
Paul

 

[HenryB123]

Hi, I am not sure. The fiat 500A had an automatic cut-out from the manual. I guess that's what you are talking about.
This is to regulate the voltage?
Later cars have a combined voltage and current regulator. Usually 2-3 coils.
The automatic cut-out has 1 coil? So very simplified.
Best to speak to a classic car electrical engineer. Try www.dynamoregulatorconversions.com
Let me know how you get on. He could possible rebuild it or supply something suitable.

 

[bugsymike]

anyone used a solid state unit in a Topolino? Can I use one from a 500? Struggling to find original one
Cheers
Paul

From a basic view point assuming you have 6 volt dynamo with a larger D wire and a smaller F wire for field windings and find a similar 6 volt regulator from a similar output dynamo using vehicle it should be fairly straight forward to wire one in, preferably one that you understand how to adjust it's output.
If not your self then a local auto electrician should have little problem fitting and setting the output to match your dynamos capacity.
Many years ago I had a 1950s BSA 650 A10 which came with a 6 volt dynamo which I was able to convert to 12 volt once I had reduced the settings on the 12 volt regulator I used, some are easier to adjust than others.
I know you are not trying to do that, all I am trying to say is that within boundaries a regulator can be adjusted to meet the capabilities of your dynamo.
Older English cars had a two bobbin regulator which was adjustable for volts and amps whilst later ones had a three bobbin regulator , often a Lucas RB340 which once cover was removed we had a special tool to set the adjustments.
It is possible if yours is older vehicle it may have been fitted with a single bobbin regulator with just a D wire from the dynamo which is more limiting in your choices of regulator. Hopefully yours is one with D and F terminals which will give a wider choice with easier adjustments for output like using a three bobbin type regulator.
There is a fair bit of information on line. What you need is an old school auto electrician as most of the younger ones probably were only trained on alternators for charging systems.
As an apprentice motor engineer in the 1960s adjusting the regulators was a common job. Just had a quick look in garage but couldn't find my adjuster for the Lucas RB340 but here is a similar one.
The reason for the need to check and adjust a new regulator is it's output may be more than your older dynamo can provide so would burn out.

 

[HenryB123]

Attached is the wiring diagram for a Fiat Topolino 500A. I guess R in the diagram is what you are referring to.

 

[bugsymike]

Attached is the wiring diagram for a Fiat Topolino 500A. I guess R in the diagram is what you are referring to.

View attachment 432886

It does look like a simple regulator system , but described as an automatic cut out? Presumably to stop over charging and disconnect when ignition off?
I see on the diagram it does appear to show a dynamo with two wires.

 

[HenryB123]

Little bit out of my league on this one. Bow down to your knowledge.
The electrical wiring on later cars is a bit different.
I have a later car so this is interesting.
If any of this is of help to original post I don't know.
What car are you referring to. 500 A B or C.

 

[flyturner]

Thanks for all the info, mine is a1953 C
Cheers
Paul

 

[HenryB123]

Generator and regulator spec for 500C.

 

[bugsymike]

My knowledge is general motor engineering, so I cannot claim any model specific Fiat detail as yourselves can, I see the generator is 12 volts which hopefully widens choices re a regulator, preferably one that it's output doesn't put too much strain on the dynamo when compared with original spec.