Littelfuse T4900.0030 - VAr Load Sharer. 415/480V 5A. The T4900 is designed to control a generator operating in parallel with the grid, or a generator operating in parallel with other generators (which are also controlled by T4900 units). The T4900 will continuously measure and compare the reactive current on the generator to an external DC reference signal connected to the “parallel line” input. The T4900 will increase or decrease the voltage of the generator (through the AVR) if it finds the reactive current level to be either too low or too high. Two built-in relays provide the increase and decrease pulses for the automatic voltage regulator (AVR). The strength (width) of the pulses is proportional to the voltage deviation. The E7800 Motorised Potentiometer can be used to adapt the contact pulses to a signal suitable for most AVR’s.
Littelfuse

T4900.0030

UPC: 079458963410

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Overview

The **Littelfuse T4900.0030 VAr Load Sharer** is a precision-engineered control unit designed to optimize generator performance in parallel operation with the grid or multiple generators. Engineered for **415/480V systems** with a **5A current rating**, this advanced device ensures stable and efficient power distribution by continuously monitoring and adjusting reactive current levels. Unlike conventional load-sharing systems that focus solely on active power, the T4900 specializes in **reactive current control**, making it indispensable for applications requiring precise voltage regulation and power quality management. **Key Features and Functionality:** The T4900 operates by continuously measuring and comparing the generator’s reactive current against an external DC reference signal connected to the 'parallel line' input. When deviations are detected—whether reactive current is too low or too high—the unit dynamically adjusts the generator’s voltage through the Automatic Voltage Regulator (AVR). This is achieved via **two built-in relays** that deliver proportional increase or decrease pulses, with pulse strength (width) directly proportional to the voltage deviation. The result is a responsive, self-correcting system that maintains optimal reactive power balance, preventing voltage instability and ensuring seamless integration with the grid or other generators. **Adaptability and Compatibility:** To enhance versatility, the T4900 can be paired with the **E7800 Motorised Potentiometer**, which adapts the contact pulses to signals compatible with most AVRs. This flexibility ensures seamless integration across a wide range of generator models and AVR configurations, reducing installation complexity and downtime. Whether deployed in industrial plants, commercial facilities, or critical infrastructure, the T4900 provides a scalable solution for parallel generator operation, supporting both conventional and modern electronic AVRs. **Industry Applications and Use Cases:** The T4900 is ideal for environments where **reliable parallel operation** is essential, including: - **Power plants** requiring load sharing between multiple generators. - **Industrial facilities** with backup power systems operating in parallel with the grid. - **Commercial buildings** where uninterrupted power quality is critical. - **Renewable energy integration** sites, such as wind or solar farms, where generators must synchronize with the grid. - **Data centers and hospitals**, where power stability is non-negotiable. **Why Choose Littelfuse?** Littelfuse is a globally recognized leader in circuit protection, power management, and industrial control solutions, with a reputation for innovation and reliability. The T4900 reflects the company’s commitment to delivering high-performance products that address the evolving needs of modern power systems. Backed by decades of expertise, Littelfuse’s solutions are trusted by engineers and operators worldwide to enhance system efficiency, reduce maintenance costs, and improve operational uptime. **Installation and Maintenance:** Designed for ease of installation, the T4900 features a compact, rugged form factor suitable for panel mounting or DIN rail installation. Its intuitive interface and clear diagnostic indicators simplify setup and troubleshooting, while the proportional relay control ensures smooth, predictable adjustments. Routine maintenance is minimal, with no moving parts to wear out, making the T4900 a cost-effective choice for long-term deployments. **Technical Specifications:** - **Voltage Rating:** 415/480V - **Current Rating:** 5A - **Control Type:** Reactive current-based voltage adjustment - **Output Relays:** Two built-in relays for AVR pulse control - **Pulse Strength:** Proportional to voltage deviation - **Compatibility:** Works with most AVRs; enhanced with E7800 Motorised Potentiometer - **UNSPSC Code:** 39122331 For engineers and facility managers seeking a **high-precision VAr load-sharing solution**, the Littelfuse T4900.0030 delivers unmatched performance, reliability, and adaptability. Whether coordinating multiple generators or ensuring seamless grid synchronization, this device is a cornerstone of modern power management systems.
  • Continuously monitors and adjusts reactive current for optimal generator performance
  • Two built-in relays provide proportional increase/decrease pulses to the AVR
  • Compatible with 415/480V systems and 5A current rating
  • Works seamlessly with E7800 Motorised Potentiometer for AVR signal adaptation
  • Ideal for parallel generator operation with grid or other generators

Specifications

Application
Industrial
Brand Name
Littelfuse
Special Features
High Quality
Sub Brand
Relay Series
Type
Protection Relays and Controls
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Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.