Generator AVR, Automatic Voltage Regulators
If your generator’s output voltage is unstable, or you’re replacing a failed AVR, you’re usually searching one of three ways: by the part number printed on the old unit, by your generator brand, or by the alternator brand, Stamford, Leroy-Somer, Mecc Alte, or Marelli Motori. Ten models are covered below, five confirmed in our current catalog, five more we can source on request.
Not sure which one fits? Send us the part number on your existing AVR, or your generator’s make and model, and we’ll confirm before you order.
Currently in catalog
ConfirmedAlso available to source
On request, stock not yet confirmedStamford AVR AS440
AS440Genuine Stamford automatic voltage regulator, manufactured in the UK and France, built for precise voltage control on Stamford-fitted diesel generator alternators.
- Genuine Stamford manufacture, not an equivalent or aftermarket copy
- Manufactured in the UK and France
- Available in 400V and 600V configurations
- Fits Stamford alternator ranges on prime and standby generators
| Part Number | AS440 |
|---|---|
| Brand | Stamford |
| Country of Origin | UK / France |
| Voltage Options | 400V, 600V |
AVR M40FA610A
M40FA610ACompatible automatic voltage regulator confirmed for Olympian, FG Wilson, and Caterpillar diesel generators, a direct replacement for failed factory-fitted units on these brands.
- Confirmed fitment for Olympian, FG Wilson, and Caterpillar generator sets
- Compact housing, straightforward like-for-like replacement
| Part Number | M40FA610A |
|---|---|
| Confirmed Fitment | Olympian, FG Wilson, Caterpillar |
| Weight | 0.80 kg |
| Dimensions | 20 x 15 x 10 cm |
AVR R250
R250Automatic voltage regulator for brushless alternators, manufactured under the Leroy Somer and Nidec brands.
- Leroy Somer / Nidec brand manufacture
- Built for brushless alternator systems
| Part Number | R250 |
|---|---|
| Brand | Leroy Somer / Nidec |
| Application | Brushless alternators, diesel and gas generators |
AVR MX341
MX341Stamford-equivalent automatic voltage regulator for brushless synchronous generators.
- Equivalent specification to Stamford MX341
- Built for brushless synchronous generator systems
| Part Number | MX341 |
|---|---|
| Type | Stamford-equivalent |
| Application | Brushless synchronous generators |
AVR AJ37-J10
AJ37-J10Compatible automatic voltage regulator offered as an equivalent to Stamford, Leroy-Somer, Mecc Alte, Basler, and Marathon models.
- Cross-compatible with Stamford, Leroy-Somer, Mecc Alte, Basler, and Marathon equivalents
| Part Number | AJ37-J10 |
|---|---|
| Compatible With | Stamford, Leroy-Somer, Mecc Alte, Basler, Marathon |
| Fitment Detail | confirm with supplier |
Marelli Motori AVR M31FA600A
M31FA600ADigital automatic voltage regulator for Marelli Motori MEC-20 control systems, suited to high-end marine and oil and gas generator sets.
- Digital, microprocessor-based control
- Built for MEC-20 platform generators
- Suited to marine and oil and gas applications
| Part Number | M31FA600A / 11000317 |
|---|---|
| Manufacturer | Marelli Motori, Italy |
| Architecture | Digital (MEC-20) |
Leroy Somer AVR R450M
R450MAnalog automatic voltage regulator built for SHUNT, AREP, or PMG excitation systems, suited to harsh marine and industrial grid environments.
- Analog, premium-grade construction
- Supports SHUNT, AREP, and PMG excitation types
- Manufactured in France
| Part Number | R450M |
|---|---|
| Manufacturer | Leroy Somer, France |
| Architecture | Analog (Premium) |
Leroy Somer AVR D350
D350Digital automatic voltage regulator with remote configuration support, built for grid-parallel operation and smart monitoring setups.
- Digital, advanced architecture
- Supports grid-parallel operation
- Remote configuration and tuning profile support
| Part Number | D350 |
|---|---|
| Manufacturer | Leroy Somer, France |
| Architecture | Digital (Advanced) |
Mecc Alte AVR DSR A6762/05
DSR A6762/05Digital signal processor based regulator for Mecc Alte ECO and ECP series alternators, with integrated diagnostic connectivity.
- DSP-based digital regulation
- Built for Mecc Alte ECO and ECP series machines
- USB and RS485 Modbus diagnostic connectivity
| Part Number | A6762/05 |
|---|---|
| Manufacturer | Mecc Alte, Italy |
| Architecture | Digital (DSP-based) |
| Supply Range | 40 to 270 VAC |
Universal AVR SX460
SX460Widely used analog automatic voltage regulator for standard standby generators, a straightforward drop-in replacement across common utility alternators.
- Analog, simple potentiometer tuning
- Suited to standard standby and rental fleet generators
- Voltage, stability, and under-frequency roll-off adjustment
| Part Number | SX460 |
|---|---|
| Type | Universal / Stamford-type |
| Architecture | Analog (Utility) |
Not sure which AVR you need?
Send us the part number stamped on your existing AVR, or your generator’s make and model, and we’ll confirm the correct match before you order.
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