Dynamo Bosch regulator - sf750

S

Smartv11

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Location
Meopham, Kent
Does the Dynamo Bosch regulator need to be earthed? is it earthed when bolted to frame?

I'm not sure what's going on as the rubber mounts are falling apart and with the frame now powder coated there won't be an earth path through the fixing bolts.

Paul
 
There is a negative terminal, D- maybe.
The regulator is not earthed via its mounting screws.
Rubber mounting is indispensable, otherwise the regulator vibrates and doesn't regulate and the battery boils and explodes and makes a big mess.

Paul
 
The regulator can fail in the other mode too, where it just goes dead and doesn't energise the field coil. Then you get no charging (as opposed to over-charging) and your battery goes flat. Usually on a dark wet night a long way from home.

If your regulator is knackered, there are solid state replacements available nowadays that are a simple plug-in fit. The solid state types would be less sensitive to vibration than the old metal case electro-mechanical type, and would presumably be more reliable because of that.

Just for completeness of info, the 3 connections to the regulator are D+, D- and DF.  This is general info, not necessarily specific to the Laverda SF.
D+ is the 12V supply from the battery via the ignition switch. This sometimes goes via a charge indicator light too.
DF is the 12V "excitation" power supply from the regulator to the field coil in the alternator (or DC generator). The job of the regulator is to switch this field coil supply on or off to maintain the system voltage.
D- is the negative, basically just an earth connection via the alternator/generator.
 
I agree with Marx on this. The Bosch Generator was latched with metal straps into an Alu shoe onto the oil pan and the D- post of the Generator is wired to the mounting post bolts for ground.

No rubber involved unless you added some and then you gotta consider the length of the belt or shims if necessary.
 
Laverda SF said:
I agree with Marx on this. The Bosch Generator was latched with metal straps into an Alu shoe onto the oil pan and the D- post of the Generator is wired to the mounting post bolts for ground.

No rubber involved unless you added some and then you gotta consider the length of the belt or shims if necessary.
Click to expand...

  The thread is about the mounting for the Regulator - not the dynamo - Regards - Phil
 
Thanks for replies,

'The regulator is not earthed via its mounting screws.'

So i don't need to scrap off powder coat to make earth point, but i do need to rubber mount it.?

the photo shows the regulator and a loop of wire off the D- on to mounting bolts, which caused my confusion.

Paul
 

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Hi Paul
Def needs rubber mounting. 
My 750 certainly has an earth connection to the frame mounting bolt, and all diagrams I've looked at show similar...but guess you could make a new strap to avoid the need to scrape off paint.  Battery is not far away....
 
The regulator isn't earthed via its' mounting bolts since it's mounted on a rubber strap.
D- goes to the dynamo which takes care of the earthing.

Paul
 
Paul Marx said:
The regulator isn't earthed via its' mounting bolts since it's mounted on a rubber strap.
D- goes to the dynamo which takes care of the earthing.

Paul
Click to expand...

Yes, i can see that would work (earth to dynamo), so will remove old hardened rubber mounts and add rubber strips to reduce vibration - Sorted :)
 
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