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A bit phased!

Posted: 23 May 2011 10:23
by Cliff
I'm trying to get to grips with understanding the charging system on my 78' Strada 3.5 (6 pole ign switch).

I know it has a flywheel alternator with six windings one of which powers the ignition ( green wire). What I want to know is how are the other 5 windings connected to produce the two field wires (yellow)? Is it a single phase alternator or a three phase? What is the red wire connected between the alternator and battery positive for?

In the case of the regulator I can see the yellow field wires connect to 2 diodes inside the aluminium box and then appear to go into a sealed unit. How is voltage control achieved? Does the sealed unit control the voltage to the battery via the brown wire? Is the sealed unit a sort of zennor diode? In books I have read full wave rectification needs 4 diodes so why only 2on the Morini?

I know I know it's a lot of questions. Sadly I worry about these things :(

any ideas much appreciated

Cliff

Re: A bit phased!

Posted: 24 May 2011 21:27
by EVguru
The alternator is 'single phase centre tapped', 'bi-phase', or 'split-phase' depending on how you want to describe it.

They're not diodes in the regulator, but SCRs (Silcon Controlled Rectifiers) which are slectively fired to provide full wave rectification when charging or not fired if the battery is 'full'.

The brown wire is the 'voltage sense' connection and comes via the ignition switch.

The regulator will not charge a battery that is too low. This means you don't fry the regulator or alternator if you have a shorted cell in the battery.

Details of the charging system can be found on the dutch website; http://www.motomoriniclub.nl/tech.html

When I got my Sport it would run Ok, but not charge. A couple of the magnets in the flywheel were very weak and re-magnetising restored things to working order.

Re: A bit phased!

Posted: 27 May 2011 09:49
by Cliff
Paul thanks for explaining it . I think I get it now! Would I be right in thinking the red wire from the alternator (effectively connected to the Battery) is the battery charging wire?

Cliff