What the Leroy-Somer R448 AVR does
The R448 is the analogue voltage regulator used on a wide range of Leroy-Somer LSA alternators — common on Caterpillar/Olympian, FG Wilson and SDMO sets in Kenya. It regulates the exciter field to hold the output voltage within about half a percent.
Unlike simpler AVRs, the R448 supports shunt, AREP and PMG excitation and accepts a droop current transformer, so it can share reactive load when generators run in parallel. Its jumper and potentiometer settings must match your alternator and application.
Signs it needs replacing
- The set runs but builds no voltage, or very low voltage.
- Unstable voltage that hunts, or slow recovery after a load step.
- Over-voltage or the regulator's fuse blowing repeatedly.
- In paralleled sets: poor reactive load sharing or circulating current.
Get the right part first time
Send us these on WhatsApp and our engineers will confirm the exact part before you pay:
- The alternator nameplate: LSA frame (e.g. LSA 46.2) and excitation type (shunt, AREP or PMG).
- A photo of your current regulator and its jumper settings.
- A photo of the generator nameplate (make, model, kVA, serial number).
Fitting notes
Copy the jumper positions and wiring from the old regulator before removing it. After fitting, set voltage, stability and the under-frequency (LAM/U/F) settings at rated speed and test on load; paralleled sets also need droop set and checked. As with any AVR, test the rotating diodes and exciter first so the new regulator is not damaged by the original fault.
Frequently asked questions
Is the R448 a digital AVR?+
No — it is analogue, adjusted with potentiometers and jumpers. Leroy-Somer's digital regulators are the D350 and D510 series.
Will an R448 work on my PMG alternator?+
The R448 supports shunt, AREP and PMG excitation, but it must be configured for the system on your alternator. Send us the nameplate and we will confirm.
Can PowerProKe set it up for paralleled generators?+
Yes. We set droop and check reactive load sharing on site so paralleled sets share load evenly.