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Littelfuse 355-200 - 3PH VOLT Monitor/190-240V/adj.VUB,TD,RD. The 355 is a 3-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance and multiple diagnostic lights. It is perfect for heavy-duty applications that need both protection and simple user-friendly diagnostics. Applications include pump panels, commercial HVAC, oil rigs and others. The 355 uses microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. The 355 can protect motors from damage caused by single-phasing, high and low voltage, phase reversal and voltage unbalance. It has four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions. Equipped with a heavy-duty 10A general purpose SPDT relay. A high voltage (600V) DPDT relay output option is available with the 400V model.

Littelfuse 355-200 3PH VOLT Monitor/190-240V/adj.VUB,TD,RD. The 355 is a 3-phase voltage monitor with…

UPC: 079458989809

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Contact for Pricing

Call +1 (262) 252-1600 (toll-free 877-268-3700) or email [email protected] for pricing and availability.

Overview

The Littelfuse 355-200 is a 3-phase voltage monitor designed for heavy-duty industrial applications requiring precise power quality monitoring. This advanced monitor continuously tracks incoming 190-240VAC line voltage to detect harmful conditions including single-phasing, high/low voltage, phase reversal, and voltage unbalance. Built with proprietary microcontroller-based circuitry, the 355-200 provides real-time protection for critical equipment like pump panels, commercial HVAC systems, and oil rigs. The unit features four diagnostic LEDs that clearly indicate overvoltage, undervoltage, voltage unbalance, reverse-phase, and normal operating conditions, enabling quick troubleshooting. With adjustable trip and restart delay settings (4 seconds for low voltage, 2 seconds for unbalance/phasing faults), the 355-200 allows customization to match specific application requirements. The heavy-duty 10A general purpose SPDT relay output provides reliable switching for control circuits. Operating across a wide temperature range of -40°C to 70°C (-40°F to 158°F), this monitor withstands harsh industrial environments. Compact dimensions of 74.42mm H x 133.86mm W x 74.93mm D (2.93" x 5.27" x 2.95") and a weight of 476.27g (1.05 lbs) make it suitable for panel mounting with #8 screws. For applications requiring higher voltage handling, consider the 355-400 (380-480VAC) or 355-600 (475-600VAC) models with enhanced relay options.
  • Monitors 190-240VAC 3-phase systems for single-phasing, high/low voltage, phase reversal, and voltage unbalance
  • Adjustable trip/reset delays: 4s (low voltage), 2s (unbalance/phasing), 2s restart delay
  • Four diagnostic LEDs for overvoltage, undervoltage, unbalance, reverse-phase, and normal conditions
  • Heavy-duty 10A SPDT relay output (15A general purpose, 480VA pilot duty at 240VAC)
  • Protects against single-phasing, high/low voltage, phase reversal, and voltage unbalance

Specifications

Brand Name
Littelfuse
Connection Type
Screw Terminal
Current Rating
10 A
Frequency
50/60 Hz
Mounting Type
Panel Mount
Operating Temperature
-40 to 158
Operating Temperature, Maximum
158
Operating Temperature, Minimum
-40
Poles
3P
Series
355
Size
74.42mm H x 133.86mm W x 74.93mm D
Special Features
5YR WARR
Standard
UL
Sub Brand
Symcom
Voltage Rating
190-240 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.
Three Phase Monitor Relay; DIN-Mount; 190-500V; 10A DPDT; Phase Loss; Reversal; Unbalance; Under/Over Voltage

PMDU

Three Phase Monitor Relay; DIN-Mount; 190-500V; 10A DPDT; Phase Loss; Reversal; Unbalance; Under/Over Voltage
CM-PVE UNDER & OVERVOLT. 3PH.

1SVR550871R9500

CM-PVE UNDER & OVERVOLT. 3PH.
Relay 460V 3 Phase Monitor

18883000015

Relay 460V 3 Phase Monitor
777-LR-KW/HP-P2 three-phase current and voltage monitor provides protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 1–2 A (looped conductors required); 2.1–9.0 A direct; 10–800 A (external CTs required).

777-LR-KW/HP-P2

777-LR-KW/HP-P2 three-phase current and voltage monitor provides protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 1–2 A (looped conductors required); 2.1–9.0 A direct; 10–800 A (external CTs required).
3PH VltMon/380-480V/VUB,TD,RD/480V rel.. The 355 is a 3-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance and multiple diagnostic lights. It is perfect for heavy-duty applications that need both protection and simple user-friendly diagnostics. Applications include pump panels, commercial HVAC, oil rigs and others. The 355 uses microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. The 355 can protect motors from damage caused by single-phasing, high and low voltage, phase reversal and voltage unbalance. It has four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions. Equipped with a 470VA @ 600VAC pilot duty SPDT relay. A high voltage (600V) DPDT relay output option is available with the 400V model.

355-400

3PH VltMon/380-480V/VUB,TD,RD/480V rel.. The 355 is a 3-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance and multiple diagnostic lights. It is perfect for heavy-duty applications that need both protection and simple user-friendly diagnostics. Applications include pump panels, commercial HVAC, oil rigs and others. The 355 uses microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. The 355 can protect motors from damage caused by single-phasing, high and low voltage, phase reversal and voltage unbalance. It has four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions. Equipped with a 470VA @ 600VAC pilot duty SPDT relay. A high voltage (600V) DPDT relay output option is available with the 400V model.
3PH VltMon/475-600V/VUB,TD,RD/480V rel.. The 355 is a 3-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance and multiple diagnostic lights. It is perfect for heavy-duty applications that need both protection and simple user-friendly diagnostics. Applications include pump panels, commercial HVAC, oil rigs and others. The 355 uses microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. The 355 can protect motors from damage caused by single-phasing, high and low voltage, phase reversal and voltage unbalance. It has four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions. Equipped with a 470VA @ 600VAC pilot duty SPDT relay. A high voltage (600V) DPDT relay output option is available with the 400V model.

355-600

3PH VltMon/475-600V/VUB,TD,RD/480V rel.. The 355 is a 3-phase voltage monitor with adjustable trip and restart delay, adjustable voltage unbalance and multiple diagnostic lights. It is perfect for heavy-duty applications that need both protection and simple user-friendly diagnostics. Applications include pump panels, commercial HVAC, oil rigs and others. The 355 uses microcontroller technology to monitor incoming voltage and de-energize its output relay if power problems exist. The 355 can protect motors from damage caused by single-phasing, high and low voltage, phase reversal and voltage unbalance. It has four diagnostic LEDs that clearly show overvoltage, undervoltage, voltage unbalance, reverse-phase and normal conditions. Equipped with a 470VA @ 600VAC pilot duty SPDT relay. A high voltage (600V) DPDT relay output option is available with the 400V model.
520CP/display NC=no Cur when c=0 4 sec. The 520CS and 520CP are fully-programmable, microcontroller-based, current-sensing devices designed to monitor 3-phase pumps. The 520CP is designed to work with motors that have ramp-up times of 4 seconds or less. The 520CS has a programmable motor acceleration time that can be set from 0-50 seconds. Both current monitors protect 3-phase motors from: Overcurrent. Undercurrent. Current Unbalance. Rapid Cycling. Single Phasing. Phase Reversal.

520CP115RX56

520CP/display NC=no Cur when c=0 4 sec. The 520CS and 520CP are fully-programmable, microcontroller-based, current-sensing devices designed to monitor 3-phase pumps. The 520CP is designed to work with motors that have ramp-up times of 4 seconds or less. The 520CS has a programmable motor acceleration time that can be set from 0-50 seconds. Both current monitors protect 3-phase motors from: Overcurrent. Undercurrent. Current Unbalance. Rapid Cycling. Single Phasing. Phase Reversal.

Frequently Asked Questions

What types of fuses does Littelfuse offer for industrial applications?

Littelfuse offers UL Class fuses, high-speed fuses, medium voltage fuses, 10 x 38 mm fuses, and solar fuses for industrial applications.

What are Littelfuse fuse blocks and holders designed for?

Littelfuse fuse blocks and holders are selected by OEMs and designers for their compact designs, indication features, and DIN-rail mounting flexibility.

What do POWR-BLOKS power distribution blocks provide?

POWR-BLOKS power distribution blocks offer a safe and convenient way to splice cables and manage power distribution requirements within panels and systems.

What is the purpose of Littelfuse feeder protection relays?

Feeder protection relays protect circuits from overcurrent, ground faults, phase loss, overload, and other detrimental conditions.

What is the Industrial Shock-Block® GFCI designed for?

The Industrial Shock-Block® GFCI is designed for people protection in industrial facilities and meets UL Standard 943C Class C and Class D.

How do high-resistance grounding systems benefit industrial applications?

High-resistance grounding limits point-of-fault damage and eliminates arc-flash hazards and transit overvoltages associated with ground faults.

What protection do Littelfuse voltage monitors offer?

Voltage monitors provide protection against both supply line and load side faults when the motor is running.

What functions do Littelfuse timers and flashers control?

Timers and flashers delay starting and stopping loads, and control cycling and sequencing of motors, pumps, compressors, heaters, and lighting.

How do Littelfuse arc-flash protection relays enhance safety?

Arc-flash relays detect a developing arc-flash incident and send a trip signal to interrupt power before significant damage occurs.

What types of motor protection does Littelfuse provide?

Littelfuse offers voltage monitors, current monitors, and Bluetooth enhanced overload relays for low and medium voltage motor protection applications.

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.