Littelfuse PLR480A - The PLR Series provides a cost effective means of preventing 3-phase motor startup during adverse voltage conditions. Proper A-B-C sequence must occur in order for the PLR’s output contacts to energize. In addition, the relay will not energize when an undervoltage or phase loss condition is present. The PLR protects a motor against undervoltage operation. The adjustment knob sets the undervoltage trip point. Operation: The output relay is energized and the LED glows when all voltages are acceptable and the phase sequence is correct. Undervoltage must be sensed for a continuous dropout delay period before the relay de-energizes. Reset is automatic upon correction of the fault condition. The output relay will not energize if a fault condition is sensed as power is applied.
Littelfuse

PLR480A

Alternate Item Number: PLR480A

UPC: 079458998030

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Overview

The Littelfuse PLR480A (SKU: PLR480A) is a cost-effective 3-phase motor protection relay designed for 480VAC industrial applications. This voltage monitoring relay, part of the PLR Series, prevents 3-phase motor startup under adverse voltage conditions, specifically undervoltage and phase loss, thereby ensuring equipment longevity and operational safety. The PLR480A continuously monitors all three phases (A-B-C sequence) and energizes its output relay only when all voltages are acceptable and the phase sequence is correct. An integrated LED indicator provides immediate visual confirmation of output status and correct phase sequence. The relay actively protects motors from damage caused by undervoltage operation, featuring an adjustable knob to set the precise undervoltage trip point. In the event of an undervoltage condition, the relay de-energizes after a continuous dropout delay period, offering a buffer against transient faults. Resetting is automatic upon correction of the fault condition, minimizing downtime and manual intervention. The PLR480A utilizes an industry-standard 8-pin octal plug connection, simplifying installation and eliminating the need for specialized connectors. Designed for systems requiring a voltage range of 380 to 500VAC, this relay is ideal for protecting critical 3-phase motors in manufacturing, HVAC systems, pumps, and processing equipment. Note: When properly adjusted and operating in an average system, a voltage unbalance of 10% or more is required for phase loss detection. For systems that require superior phase loss protection where regenerated voltages during single phasing exceed 10%, Littelfuse recommends the PLMU Series. Country of Origin: US. UNSPSC Code: 39122332.
  • Prevents 3-phase motor startup during undervoltage or phase loss conditions.
  • Monitors A-B-C phase sequence for correct operation.
  • Features an adjustable knob for setting the undervoltage trip point.
  • Provides quick visual indication of output status with an LED indicator.
  • Utilizes an industry-standard 8-pin octal plug connection for easy installation.

Specifications

Brand Name
Littelfuse
Connection Type
8-pin octal plug
Frequency
50/60 Hz
Operating Temperature
0 to 55 F
Operating Temperature, Maximum
55 F
Operating Temperature, Minimum
0 F
Poles
3P
Series
PLR
Special Features
10Y WARR
Standard
CE/UR/CSA
Sub Brand
SSAC
Voltage Rating
380-500 V
Voltage Rating
480 VAC
Package Dimensions (L x W x H)
1.78 IN x 2.39 IN x 3.2 IN
Package Dimensions (L x W x H)
45.2 mm x 60.7 mm x 81.3 mm
The PLR Series provides a cost effective means of preventing 3-phase motor startup during adverse voltage conditions. Proper A-B-C sequence must occur in order for the PLR’s output contacts to energize. In addition, the relay will not energize when an undervoltage or phase loss condition is present. The PLR protects a motor against undervoltage operation. The adjustment knob sets the undervoltage trip point. Operation: The output relay is energized and the LED glows when all voltages are acceptable and the phase sequence is correct. Undervoltage must be sensed for a continuous dropout delay period before the relay de-energizes. Reset is automatic upon correction of the fault condition. The output relay will not energize if a fault condition is sensed as power is applied.

PLR240A

The PLR Series provides a cost effective means of preventing 3-phase motor startup during adverse voltage conditions. Proper A-B-C sequence must occur in order for the PLR’s output contacts to energize. In addition, the relay will not energize when an undervoltage or phase loss condition is present. The PLR protects a motor against undervoltage operation. The adjustment knob sets the undervoltage trip point. Operation: The output relay is energized and the LED glows when all voltages are acceptable and the phase sequence is correct. Undervoltage must be sensed for a continuous dropout delay period before the relay de-energizes. Reset is automatic upon correction of the fault condition. The output relay will not energize if a fault condition is sensed as power is applied.
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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.