Regulator/Rectifier advice

S

SeeDoubleYou

Junior member
Morning. My 500 reg/rec has been replaced with what looks like a Ducati unit. Looking at t'internet in various places it looks like a common unit although physically difference of course. The problem is I can't be sure how to connect it and thought I'd start here to see if someone can advise. Essentially it has 5 terminals with the case being grounded on the frame. The 5 connections are G, G, +B, C, L.

Any ideas?
 
SeeDoubleYou said:
Morning. My 500 reg/rec has been replaced with what looks like a Ducati unit. Looking at t'internet in various places it looks like a common unit although physically difference of course. The problem is I can't be sure how to connect it and thought I'd start here to see if someone can advise. Essentially it has 5 terminals with the case being grounded on the frame. The 5 connections are G, G, +B, C, L.

Any ideas?
Click to expand...

The leads from most italian alternators of the time were coloured yellow/giallo, these would connect to "G".  B+ is +12V to battery.  Either "C" or "L" would be charge light or ground respectively.  Nothing much to lose through switching these connections if revs are kept low and an eye on a voltmeter.

Many R/R units have a seperate ground connection, simply don't rely on the casing having proper earthing.  A good ground connection for the casing aids heat transfer.

piet
 
Hi,
what you got  there is is a full-bridge R/R usually applied in the Vespa Ape50 3-wheelers.

I do not know how the Monty alternator is set up, but full-bridge means your alternator windings should not be grounded when this R/R unit is used, instead the alternator should provide a wire from each end of its coil windings towards the RR. Those two wires need to be connected to the two 'G' connectors of the R/R unit.

'B+' needs to be connected to the battery's positive terminal.

'C' is the sense connector, needs to be supplied with switched 12V+ (via ignition key switch).

'L' is the charging light connector, it will be grounded in case no battery charge is detected. Ground wire of your charge control light goes to this connector.

Ground connection of this R/R unit is provided by the casing, so needs a good earth connection, either by bolting it to the bike's frame or (better) by runing a separate ground cable to one of the bolts holding the R/R unit in place.
 
Recently bought one for my monty rebuild it was about ?60 - I'll find the detials wen I get home - it was from a place in sussex.. easy to set up if I can do it.
 
I have several new and used single phase rec/reg's
yours for the cost of a beer or two if you come and collect, your profile does not tell me where you live, I am 25 miles due south of London
Clem
 
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