6 replies to this topic

[croc7]

Am chasing a red warning light (generator) on the MG1100-I know, its not a mini but Lucas is Lucas. Completed all the usual checks; wiring & grounding points. Replaced V Reg, still warning light on. Last was to replace the generator and polarization of generator. Red light out. That’s good but don’t know if the V Reg is doing the job correctly. The Lucas RB 340 V Reg currently installed is not adjustable. The question is, am I able to read regulated generator output voltage at the battery terminals? Currently reading 12.45 volts, engine running & is that adequate? My alternator equipped mini reads 14.6 at the battery terminals, engine running.
Thanks

[timmy850]

12.4v sounds like it isn’t charging. Does it increase in voltage when you increase the rpm?

[Spider]

,,,,,, The question is, am I able to read regulated generator output voltage at the battery terminals?

 

Yes.

As Timmy has said, it doesn't sound like it's charging. With the engine at 2000 RPM or higher, you should see 13.5 Volts or more.
 

[mad4classics]

As Spider alluded to, you need to run the engine at a bit of a lick to get a meaningful reading...

 

Some info on the RB340 here:-

 

https://www.lrsoc.co...orkshop-manual/

 

Section B5

[weef]

If the voltage regulator is a genuine Lucas RB340 it has adjustments on the coils. There should be adjustable cams at the back of the coils, by the back I refer to the front as  being the terminal side. 

The charging voltage output is in the region of 12.7 to 13.4 volts dependant on load conditions. Setting up and adjusting these regulators is a long drawn out task and too long to explain here. There will be I have no doubt explanations on how to do this on the internet, Google Lucas RB340 voltage regulator set up.

There are some very poor examples of  "new" voltage regulators out there, so do not be surprised if the replacement unit is faulty.

Measuring the current output of the unit, Max 22 amp, is an indication of the system health, put on all the vehicle electrical loads and measure the charge current. 

[croc7]

As Spider alluded to, you need to run the engine at a bit of a lick to get a meaningful reading...

 

Some info on the RB340 here:-

 

https://www.lrsoc.co...orkshop-manual/

 

Section B5

Thanks for the information.

[croc7]

As Spider alluded to, you need to run the engine at a bit of a lick to get a meaningful reading...

 

Some info on the RB340 here:-

 

https://www.lrsoc.co...orkshop-manual/

 

Section B5

Just printed this info and was gratified to see how well the Lucas workshop instructions are written and more easily understood than the shortened version in both of my manuals.  Thanks again.