Overview

The Leroy Somer D350 Automatic Voltage Regulator (AVR) is a state-of-the-art digital control system engineered to maintain precise voltage output in generator applications requiring rated field current up to 5 amperes. Designed by Leroy Somer, a global leader in alternator technology, the D350 AVR provides superior voltage regulation performance for industrial, commercial, and backup power generation systems. This advanced digital regulator automatically adjusts the excitation current supplied to the alternator's rotor winding, ensuring stable, consistent voltage output regardless of load variations or engine speed fluctuations. The D350 represents the next generation of voltage regulation technology, offering enhanced accuracy, reliability, and diagnostic capabilities that far exceed traditional analog AVR systems.

What sets the D350 apart from conventional voltage regulators is its programmable digital architecture and comprehensive monitoring capabilities. The unit can be fully configured using Leroy Somer EasyReg Advanced software, allowing technicians to customize parameters to match specific application requirements and optimize generator performance. The D350 features an integrated event logger function that records operational data and fault conditions, making troubleshooting and preventive maintenance significantly easier and more effective. Additionally, the optional NFLink® wireless communication module enables remote parameter configuration and data retrieval without the need for physical connection to the unit, streamlining commissioning and service procedures. Fully compliant with IEC 60034 international standards, the D350 delivers the reliability and performance demanded by mission-critical power generation applications worldwide.

Key Specifications

Compatible Alternator Models

The D350 Leroy Somer AVR is designed for seamless integration with a wide range of Leroy Somer alternator series and select compatible generator models. This voltage regulator is specifically engineered to work with Leroy Somer LSA alternator series including LSA 36, LSA 40, LSA 42, LSA 43, LSA 44, LSA 46, LSA 47, and LSA 49 models that require field current ratings up to 5 amperes. The D350 is also compatible with various Leroy Somer TAL alternator series and selected industrial generator sets in the 10 kVA to 500 kVA power range. Additionally, this AVR works with generator systems featuring brushless excitation configurations where precise digital voltage control is required. When selecting the D350 for your alternator, it is essential to verify the field current requirements and ensure compatibility with your specific alternator model number. The regulator is widely used in applications including standby power systems, prime power generation installations, rental generator fleets, marine power systems, telecommunications backup power, and industrial cogeneration facilities. For precise compatibility confirmation with your specific Leroy Somer alternator model or generator set configuration, contact our technical support team who can cross-reference your equipment specifications and confirm that the D350 is the correct AVR replacement for your application.

Why Buy from General Power

When you purchase your D350 Leroy Somer AVR from General Power, you're partnering with an authorized distributor of genuine OEM generator parts with over two decades of industry experience. We stock only authentic Leroy Somer factory original components, ensuring you receive the exact same quality and performance as the AVR that was originally installed in your generator. Our commitment to customer satisfaction includes same-day shipping on in-stock orders placed before our cutoff time, minimizing your equipment downtime and getting your generator back online quickly. General Power provides comprehensive bilingual technical support in both English and French, with knowledgeable specialists available to assist with product selection, installation guidance, and troubleshooting. Our team understands the critical nature of power generation equipment and is dedicated to providing the expertise you need to maintain reliable operation. We back every D350 AVR with full manufacturer warranty coverage and stand behind the quality of every component we sell. Whether you're a service technician, facility maintenance manager, or equipment owner, General Power delivers the product availability, technical knowledge, and customer service that keeps your operation running smoothly. Call us today at 1-888-769-3758 to speak with a generator parts specialist, verify compatibility with your specific alternator model, or place your order for fast delivery.

Installation Overview

Installing the D350 Leroy Somer AVR requires basic electrical knowledge and adherence to proper safety procedures. Before beginning any installation work, disconnect all power sources to the generator and alternator, including battery connections, and allow capacitors to fully discharge. Verify the alternator is completely de-energized using appropriate testing equipment before proceeding with AVR replacement.

Step 1: Remove the Existing AVR - Locate the current voltage regulator mounted on or near the alternator assembly. Document all wire connections by photographing or labeling each terminal before disconnection. Carefully disconnect all wiring harnesses, noting the position and connection point of each wire. Remove the mounting screws or fasteners securing the old AVR and carefully remove the unit from its mounting location.

Step 2: Mount and Connect the D350 AVR - Position the new D350 voltage regulator in the same mounting location as the previous unit, ensuring adequate ventilation around the heat sink surfaces. Secure the AVR using appropriate fasteners, ensuring the unit is firmly mounted to prevent vibration damage. Reconnect all wiring harnesses according to the terminal identification markings on the D350 and your documentation from the removal process. Typical connections include sensing inputs (voltage and current transformers), excitation output to the alternator field winding, power supply connections, and any auxiliary control circuits. Ensure all connections are tight and properly seated to prevent intermittent operation or connection failures.

Step 3: Configure and Test - If using programmable features, connect the D350 to a computer running EasyReg Advanced software or use the optional NFLink® wireless module to configure parameters according to your alternator specifications and application requirements. Restore power connections and start the generator under no-load conditions. Monitor voltage output and verify proper regulation performance. Gradually apply load while observing voltage stability and regulator response. Check for proper operation across the full load range and verify that voltage remains within specified tolerances. Record all settings and configuration parameters for future reference.

Step 4: Final Verification - Conduct a comprehensive functional test including load acceptance, load rejection, and steady-state operation to confirm the D350 is regulating voltage correctly under all operating conditions. Verify proper operation of any connected protection systems or auxiliary controls. Document the installation date, configuration settings, and initial performance data for maintenance records. For complex installations or if you encounter any difficulties during installation, consult the complete Leroy Somer D350 installation manual or contact technical support for assistance.

Frequently Asked Questions

Q: What does the D350 Automatic Voltage Regulator do?
A: The D350 AVR is the critical control component that maintains constant voltage output from your generator's alternator regardless of load changes or engine speed variations. It continuously monitors the generator's output voltage and automatically adjusts the excitation current supplied to the alternator's rotating field winding to keep voltage stable within specified tolerances. The digital technology in the D350 provides superior accuracy compared to analog regulators, with regulation precision of ±0.5% to ±2.5%. This ensures your connected equipment receives clean, stable power and protects sensitive electronics from voltage fluctuations that could cause damage or malfunction. The D350 also includes programmable features that allow customization for specific applications and advanced diagnostics capabilities for easier maintenance and troubleshooting.

Q: How do I know if my D350 AVR is failing?
A: Several symptoms indicate AVR failure or deterioration. The most common signs include erratic voltage output that fluctuates unpredictably even under steady load conditions, inability to maintain proper voltage (output consistently too high or too low), slow response to load changes where voltage dips or surges take longer than normal to stabilize, complete loss of voltage output despite the engine running normally, or intermittent regulation where the generator works properly sometimes but fails at other times. You may also notice the generator failing to build voltage during startup, overheating of the AVR unit itself, visible damage to components, or diagnostic lights indicating fault conditions. If you're experiencing any of these symptoms, the D350 AVR should be tested and likely replaced. The event logger function in the D350 may also record fault codes that can help diagnose problems before complete failure occurs.

Q: Is this an OEM Leroy Somer part or an aftermarket replacement?
A: General Power supplies only genuine OEM (Original Equipment Manufacturer) Leroy Somer parts. The D350 AVR we sell is the authentic factory-original component manufactured by Leroy Somer to exact specifications. This is the identical part used in new Leroy Somer alternators and recommended by the manufacturer for replacement applications. OEM parts ensure proper fit, correct performance characteristics, full compatibility with your alternator's design, and compliance with all safety and quality standards. Aftermarket or counterfeit voltage regulators may appear similar but often use inferior components, lack proper quality control, and may not provide the regulation accuracy or reliability of genuine OEM parts. Using authentic Leroy Somer OEM parts also maintains warranty coverage and ensures you're getting a component backed by the manufacturer's engineering and quality standards.

Q: What warranty coverage comes with the D350 AVR?
A: The genuine OEM Leroy Somer D350 AVR purchased from General Power includes the manufacturer's standard warranty coverage against defects in materials and workmanship. Warranty terms typically cover replacement or repair of defective units within the warranty period when used in accordance with manufacturer specifications and proper application guidelines. Specific warranty duration and terms are provided with your purchase and may vary based on application type. To maintain warranty validity, the D350 must be installed according to manufacturer instructions, operated within specified parameters, and not subjected to abuse, improper voltage levels, or environmental conditions beyond rated limits. General Power stands behind every component we sell and will assist with warranty claims processing if issues arise. For complete warranty details specific to your purchase, contact our customer service team at 1-888-769-3758.

Q: Can I get technical support for installation and configuration?
A: Absolutely. General Power provides comprehensive technical support for all products we sell, including the D350 Leroy Somer AVR. Our knowledgeable specialists can assist with pre-purchase compatibility verification, installation guidance, configuration recommendations, troubleshooting assistance, and answers to technical questions about operation and maintenance. We offer bilingual support in English and French to serve our diverse customer base. Technical support is available via phone at 1-888-769-3758 during business hours, and we can also provide email support for non-urgent technical questions. For complex configuration requirements using EasyReg Advanced software or NFLink® wireless communication features, our team can provide guidance on parameter settings appropriate for your specific application. Whether you're an experienced generator technician or a facility manager handling your first AVR replacement, we're here to ensure successful installation and optimal performance of your D350 voltage regulator.

Order Today

Don't let a failed voltage regulator keep your critical power generation equipment offline. The D350 Leroy Somer AVR is in stock at General Power and ready for immediate shipment to get your generator back to reliable operation quickly. As an authorized distributor of genuine OEM Leroy Somer parts, we guarantee you're receiving an authentic factory-original component with full warranty coverage and the quality you expect from this industry-leading manufacturer. Our same-day shipping on orders placed before our cutoff time means minimal downtime for your equipment, and our knowledgeable technical support team is available to ensure you're ordering the correct part and to assist with any installation questions. Whether you're replacing a failed AVR, stocking critical spare parts, or upgrading your generator's voltage regulation system, General Power delivers the genuine parts, expert knowledge, and customer service that power professionals depend on. Call 1-888-769-3758 now to speak with a generator parts specialist, verify compatibility with your Leroy Somer alternator, and place your order for the D350 AVR. You can also order online through our secure website for 24/7 convenience. Trust General Power for genuine Leroy Somer parts, competitive pricing, fast shipping, and the technical expertise that keeps your power generation systems running at peak performance.