Hi all,

this is my first post so forgive me if I am writing about something that makes all you harden lister veterans eyes roll.

I have purchased a 6/1 SOM which I am struggling to find any details of or even an image of one that looks like mine.

Basically it came out of an Exeter police station ... I am guessing it is quite an early one.

The strange thing is it has two gen heads connected by a shaft , one says "generator" on it and I have put 24V into this and the belt happily drives the lister and starts it , the other head says "alternator" 220 -240v ....

My question is I cant work out how the batteries get charged the "generator head" does not seem to put out any voltage (yet happily spins when I apply voltage , is there a blocking dioide preventing the current going back??) 

also it seems like the AC alternator needs excitement to work (would I be right in those thoughts ? if so does excitement need a permanent 24v DC feed?

sorry to ask but I am totally new to a SOM but .. I have to say what an awesome piece of engineering )))