Replacement Voltage Regulator

[tankstraddler]

I have a 1974 Strada and need to source a replacement voltage regulator. I believe that the early models like mine used a different regulator from later versions. Given the unavailability of the original item, does anyone have any recommendations for a suitable replacement based on their own satisfactory experience? Thanks.

[EVguru]

Regulator was the same up until the early 80's I think.

Are you missing a regulator, or do you have one you think is broken?

[Ralph]

I fitted a NLM one some time back 2011 it is still running fine.

viewtopic.php?f=4&t=1937

[tankstraddler]

Paul, I have an original regulator fitted but think that it is broken as I am getting about 18v across the battery terminals with the engine running fast. Ideally I would like to find a working original given Ralph's thread although I am pleased to see that he is sorted.

[EVguru]

Measure the voltage on the brown wire terminal. Both to battery negative and to the regulator case.

[tankstraddler]

Thanks, Paul. With the engine off I had 11.6v across the battery terminals. With the engine running at 4,000 rpm I had the same reading of 15.6v across the battery terminals, brown contact to negative battery terminal and brown contact to regulator case. The battery has seen better days and does not hold a charge for long which I mention just in case it should be relevant.

[EVguru]

That's quite a high voltage, but not stupidly so. It could be due to the old battery being high impeadance.

I'd try a good battery in there before you do anything else.

[tankstraddler]

Thanks Paul. Will do as you suggest then report.

[tankstraddler]

New battery fitted and fully charged. Engine off I get 13.2v across the terminals and 12.9v brown terminal to negative pole and brown terminal to regulator body. Engine running at 5,500 rpm I get 14.2v across the terminals and 14.0v brown terminal to negative pole and brown terminal to regulator body. It looks like the battery was the culprit and the voltage regulator OK so thanks Paul and Ralph.

[norbert]

The first regulators were out of sheet metal (don´t know if it is the right word), that could be opened.

In 1978 there have been some changes like the new wheels, a better gearbox, the rubber intakes and a new alternator that now gives about 120W (the first ones 100W). This was achieved by increasing the metallic nucleos from 10,5 to 14 mm. The new regulator now was the closed one you couldn´t open any more, with 18 A. This update was completed by the new flywheel.You can use the first and the second generation of regulators for this twoo types of alternators. The great advantage of this second alternator is not only the 20W more, it begins to charge about 1000 rev less!

In 1979 they needed to rise the eficacy of the alternator, introducing the 500 and the electric starters. This new alternator produces 140W (well, that´s what Ducati Elettronica said). The wiring sistem was completely changed and with this alternator you need a new regulator. We call him a "bridge-regulator". It has some diodes that it makes posible to use all the wiring! Before half of the wiring was lost! This new alternator has no red cable, only twoo yellow, one green an a white one. The regulator has a port B+! from this one a red cable goes to the batery. With this alternator you normaly can go in city traffic even with H4 light on without problems! If you invest in a new regulator, you can have a much better performance with a 350 alternator, if you change the wiring to the sistem of the 500 alternator!

After that, I don´t know exactly when, came the last evolucion of the generators: we call him the "without body". The cable was wired directly on the nucleos without that plastic bodies, so they could make the nucleos even fatter, now 16mm (the ignicion coil keeps the 10,5 mm of the first serie ). This one gives 200W. And they came with the best flywheels ever, withe the strongst magnets. You can identify them easily: there are marks ANT1 and ANT2 and this as well for the 350 and the 500. The regulator as well is a "bridge"one, now 28 A. This alternator you can find for example in the Camel 501 Electric Start, the Kanguro X3 (don´t know if in the X2) and in all the customs that still do not have the Kokussan sistem.
This was the last update of the marriage with Ducati Elettronica. After that, allready in hands of Cagiva they Began to use the Kokussan sistem.

I realy don´t understand much of all That electric stuff. But a few days ago I posted all this at the spanish forum to help some friends. There you can find somo fotos of all that stuff http://www.lamaneta.org/forolamaneta/vi ... 65&t=10654
First foto: first generacion
second foto: wiring sistem of the first generation
third foto: 1-3 second genaration, foto 4 the bodyless altenator, foto 5 the 28A regultor
foto n.4; wiring sitem of the 140W alternator (500 ccm)
foto 5 and 6: the bodyless alternator

hope that this info might be helpful for some of you

norbert

[tankstraddler]

Norbert, thanks very much for this interesting and informative post.

[sheddweller]

I have read this post and all previous ones I could find on the wiring for the regulator and am still struggling.
My 350 Sport is a later, electric start model, with a single front disc and drum rear, perhaps 1979 model.
I got it in parts from japan, and the original, metal cased Regulator rectifier was heat damaged.
With the bike came a Ducati Energia Regulator/Rectifier, with the numbers 9512 and 343520 stamped on it.
It has a Black plastic cover above the 6 Spades which are labelled G G R +B L C. This looks very similar to the Reg/Rec that Paul C mentioned as asuitable replacement some time ago.
My Stator has 2 Yellow, Which I believe to supply AC to the Reg, and go onto the G spades
1Red, which I also believe to supply AC, and I thought would go to the R Spade
1 White, which I think is an additional Earth, and have wired to Earth
1 Green, which I have put to the igniton with diode
I have run a heavy wire from the Positive battery terminal to the +B Spade
and a wire to supply switched 12V power from the ignition switch to the C Spade
I have wired in a charge light to the L spade.
I haven't started the engine, but at rest with the ignition on, this set up does not light up the charge light, or fire the electric start (which works fine with direct power)
What have I got wrong???
The bike has been rewired by an Engineer, and I'm using a modern Fusebox.
Please don't use numbers to describe the roles of the spades in the Reg/Rec as mine doesn't have any. (NLM have sent me their numbered diagram). I can't find a wiring diagram that matches my bike either.
Garry

[EVguru]

From what I've been able to find quickly on that rectifier, it's a single phase full bridge. Don't use the red wire from your stator, that's a centre tap for the single phase half wave rectifier.

[sheddweller]

Paul,
Thanks heaps for the wiring diagram. Is there somewhere that provides those wiring diagrams to the public?
It's no problem to cap the red wire off. Should the R Spade remain unused then?
Garry