Littelfuse 350-400-2 - 3PH VOLT mntr/380-480V/adj.RD/480V Rly. The 350 is a heavy-duty voltage monitor. This product should be used when high current relays or dual contacts are required, or 480V controls are used. Since the 350 uses heavy-duty relays, it comes in fixed voltage range models rather than a dual autoranging version like the Model 250. The 350-200 has a 15A general purpose contact. The 350-400 provides a SPDT (Form C) relay rated to switch up to 600V, allowing the use of 480V controls, eliminating the need for a control power transformer to step the voltage down to 120-240V. Several DPDT (two Form C contacts) relay models are also available. The 350 microcontroller-based family of products are low cost yet highly advanced solutions to heavy-duty problems. The 350 includes advanced single LED diagnostics. Five different light patterns distinguish faults and normal operating conditions. Other options such as high voltage trip and adjustable restart delay are available.
Littelfuse

350-400-2

UPC: 079458989892

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Overview

The Littelfuse 350-400-2 is a robust, heavy-duty 3-phase voltage monitor engineered for demanding industrial environments. Designed to safeguard critical motor and control systems, this unit excels in applications where high current relays or 480V control circuits are utilized. Unlike auto-ranging models, the 350 Series features fixed voltage ranges, ensuring precise monitoring for specific operational parameters. The 350-400-2 model is equipped with a Single Pole Double Throw (SPDT) Form C relay, uniquely rated to switch up to 600V. This high voltage rating is a significant advantage, as it directly supports 480V control circuits, thereby eliminating the costly and complex requirement for a control power transformer to step down voltage to 120-240V. At its core, the 350 Series employs advanced microcontroller-based circuitry, offering a sophisticated yet cost-effective solution to complex industrial protection challenges. This technology enables constant monitoring of all three phases, providing protection against harmful line conditions even before a motor is energized. Troubleshooting and status determination are streamlined thanks to the advanced single LED diagnostic indicator. This LED employs five distinct light patterns, clearly distinguishing between various fault conditions and normal operating states, significantly reducing downtime and simplifying maintenance procedures. Key features and benefits of the Littelfuse 350-400-2 include: * **Proprietary Microcontroller-Based Circuitry:** Continuously monitors 3-phase voltage to protect against harmful line conditions, even before the motor starts. * **Advanced LED Indication:** Provides clear diagnostics for troubleshooting and relay status. * **600V Rated Relay Contacts:** Available on select models (like the 350-400-2) to eliminate the need for control transformers for 120-240V control circuits. * **Heavy-Duty Design:** Built to withstand the rigors of industrial applications. * **Fixed Voltage Range:** Ensures precise monitoring for specific operational requirements. Additional options, such as high voltage trip detection and an adjustable restart delay (as seen in the -2 suffix models), further enhance the versatility and protective capabilities of the 350 Series. The adjustable restart delay, for instance, is crucial for preventing low voltage conditions during staggered start-ups of multiple motors following a fault. The 350-400-2, with its 380-480VAC operating range and SPDT 600V relay, is an ideal choice for motor control centers, pump stations, HVAC systems, and any industrial process where reliable 3-phase voltage monitoring and robust switching are paramount. Littelfuse is a trusted name in circuit protection, and the 350 Series continues this legacy with advanced technology and dependable performance.
  • Heavy-duty 3-phase voltage monitor for industrial applications.
  • Supports 380-480VAC line voltage.
  • Features a SPDT (Form C) relay rated to switch up to 600V.
  • Eliminates the need for a control power transformer for 480V controls.
  • Microcontroller-based circuitry with advanced single LED diagnostics (5 patterns).

Specifications

Brand Name
Littelfuse
Operating Temperature
-40 to 158
Operating Temperature, Maximum
158
Operating Temperature, Minimum
-40
Special Features
5YR WARR
Standard
UL/CSA/CE
Sub Brand
Symcom
Voltage Rating
380-480 V
The 201A-AU is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190-480VAC, 50/60Hz motors regardless of size. Has user adjustable 1-30 second trip delay, manual or 1-500 second restart delay, and 2-8% voltage unbalance trip point. The product also provides a user selectable nominal voltage setpoint and the voltage monitor automatically selects between the 200V and 400V range. The Model 201A-AU includes advanced single LED diagnostics, where five different light patterns distinguish between faults and normal conditions. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions. When a harmful condition is detected, the 201A-AU's output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to acceptable levels.

201-575-AU

The 201A-AU is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190-480VAC, 50/60Hz motors regardless of size. Has user adjustable 1-30 second trip delay, manual or 1-500 second restart delay, and 2-8% voltage unbalance trip point. The product also provides a user selectable nominal voltage setpoint and the voltage monitor automatically selects between the 200V and 400V range. The Model 201A-AU includes advanced single LED diagnostics, where five different light patterns distinguish between faults and normal conditions. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions. When a harmful condition is detected, the 201A-AU's output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to acceptable levels.
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CM-PVE UNDER & OVERVOLT. 3PH.

1SVR550871R9500

CM-PVE UNDER & OVERVOLT. 3PH.
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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.