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AVR modules, excitation components, and replacement parts for Stamford, Leroy-Somer, Mecc Alte, Cummins, and Onan alternator systems.

Stamford / AvK Leroy-Somer Mecc Alte Cummins / Onan Components
Brand
Stamford / AvK
World's leading manufacturer of AC generators. CrestGen stocks AVR modules, excitation components, and ancillary parts for the full Stamford / AvK range.
AVR Module
MX321
Automatic Voltage Regulator

Compact analogue AVR for single or three-phase sensing. Widely used on UC/UCI/UCM/UCD series alternators. Tight regulation with remote trim capability.

SensingSingle or 3-phase
Regulation±0.5% no load to full load
Input Range95–132V / 170–264V AC
Frequency50 or 60 Hz
MX321
AVR Module
AS440
Automatic Voltage Regulator

Half-wave phase-controlled thyristor AVR for brushless excitation. Built-in EMC filter. Adjustable stability, voltage, and droop for a wide range of Stamford generators.

TypeHalf-wave phase controlled
Regulation±1% (±0.5% optional)
Exciter Output90V DC / 4A max
Droop0–5% adjustable
AS440
AVR Module
MX341
Automatic Voltage Regulator

Half-wave sensing AVR designed for single-phase sensing. Common on older HC/HCK series alternators. Rugged industrial design with remote voltage trim.

SensingSingle-phase
Regulation±1% no load to full load
OutputUp to 180V DC / 3A
Remote Trim±10% via external pot
MX341
AVR Module
SX460
Automatic Voltage Regulator

Half-wave phase-controlled AVR with built-in soft start (2–5 second ramp). Ideal for single and two-bearing alternators up to 150kVA in UC/UCI/UCM/UCD frames.

Soft StartBuilt-in (2–5 sec ramp)
Regulation±1% no load to full load
Sensing Input170–240V AC
Max Continuous150kVA
SX460
AVR Module
SX440
Automatic Voltage Regulator

Full-wave bridge sensing AVR for demanding applications. Supports droop CT for parallel operation. Better transient response than half-wave designs. Wide temperature range.

SensingFull-wave bridge
Regulation±0.5% steady state
Parallel Op.Droop CT supported
Temp Range-40°C to +70°C
SX440
Digital AVR
DVR2000E
Digital Voltage Regulator

Advanced digital AVR with RS232/RS485 communications, programmable PID control, and comprehensive protection. Designed for critical standby and prime power applications.

ControlDigital PID
Regulation±0.25% steady state
CommsRS232 / RS485
ProtectionOV, UV, Overcurrent
DVR
Brand
Leroy-Somer
Premium French-engineered alternators trusted in critical standby and prime power applications worldwide. CrestGen stocks AVR modules and key components.
AVR Module
R438
Automatic Voltage Regulator

Digital AVR with very precise voltage regulation. Supports parallel operation with reactive current compensation. Suitable for LSA/LSA+ series alternators.

Regulation±0.5% steady state
Sensing3-phase
Parallel Op.Reactive current comp.
Frequency50 / 60 Hz
R438
AVR Module
R449
Automatic Voltage Regulator

Enhanced digital AVR with improved regulation and diagnostics. Used on larger LSA 46–49 series Leroy-Somer alternators. PMG compatible for independent excitation.

Regulation±0.5% no load to full load
PMG CompatibleYes
Frame SeriesLSA 46–49
ProtectionOV, UV built-in
R449
Excitation
D350
Shunt Excitation AVR

Basic analogue AVR for shunt-excited Leroy-Somer alternators. Reliable, low-cost solution for standby power applications with less demanding regulation requirements.

TypeShunt excitation
Regulation±2.5% no load to full load
Power Factor0.8 to unity
ApplicationStandby/prime power
D350
Brand
Mecc Alte
Italian-manufactured alternators renowned for robustness and efficiency. CrestGen supplies AVR modules and components for the full Mecc Alte range.
AVR Module
SX460-A
Analogue Voltage Regulator

Mecc Alte compatible analogue AVR. Suitable for single-phase and three-phase brushless alternators in the ECO and ECP series. Drop-in compatible design.

SeriesECO / ECP
Regulation±1.5% no load to full load
SensingSingle-phase
Frequency50 / 60 Hz
SX460
Digital AVR
DSR
Digital Sensing Regulator

Advanced digital AVR for Mecc Alte ECP/ECO 3–5 series. Digital PID control with remote monitoring capability and comprehensive protection features.

ControlDigital PID
Regulation±0.5% steady state
SeriesECP/ECO 3–5
ProtectionOV, UV, Loss of sensing
DSR
Brand
Cummins / Onan
North America's most widely deployed generator brand for commercial standby applications. CrestGen supplies control boards, AVRs, and replacement components.
Control Board
OTPC
Onan Transfer & Protection Control

Replacement control boards for Cummins/Onan commercial DQGAB, DQCA, and DQCB generator series. Fully tested prior to dispatch.

CompatibleDQGAB / DQCA / DQCB
TypeReplacement control board
TestingPre-dispatch bench tested
Warranty12 months
OTPC
AVR Module
AVR-150
Cummins AVR Replacement

Direct replacement AVR for Cummins commercial standby alternators. Compatible with QSB, QSL, and QSX generator series. Plug-and-play installation.

CompatibleQSB / QSL / QSX series
Regulation±1% no load to full load
InstallPlug-and-play
Frequency60 Hz
AVR
Component
Onan PCB
Printed Circuit Board Assembly

Replacement PCB assemblies for Onan residential and commercial generator control systems. Covers HGJAB, HGJAC, HGJAE, and HGJAF series transfer switches.

CompatibleHGJAB / HGJAC / HGJAE
TypePCB Assembly
Lead TimeIn stock / 1–3 days
Warranty12 months
PCB
Universal Components

Ancillary Parts & Accessories

Common replacement components stocked for all major alternator brands. Can't find what you need? Contact us — if we don't have it, we'll source it.

Excitation Diodes
Rotating rectifier diode sets for all Stamford, Leroy-Somer, and Mecc Alte frame sizes. Standard and surge-rated options.
Varistors (MOV)
Metal oxide varistors for rotating rectifier surge protection. Compatible with HC, UCI, UCM, UCD, and LSA frames.
PMG Assemblies
Permanent magnet generator pilot exciter assemblies for independent excitation under fault conditions.
Bearings & Seals
OEM-spec main and DE/NDE bearing replacements for all popular Stamford, Leroy-Somer, and Mecc Alte frames.
Excitation Capacitors
Excitation and power factor correction capacitors for self-excited alternator models across all major brands.
Droop CTs
Current transformers for reactive power load sharing during parallel generator operations.
Brush Gear
Carbon brushes and brush holders for brushed alternator variants and exciter assemblies.
Terminal Boards
Reconnection and terminal block assemblies to support various voltage and phase configurations.
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