Littelfuse SCR630T - The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.
Littelfuse

SCR630T

Alternate Item Number: SCR630T

UPC: 079458998535


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Overview

The Littelfuse SCR630T is a universal lamp alarm relay engineered for 230VAC incandescent beacon and obstruction lighting systems. This critical safety device reliably detects lamp failures in flashing or steady configurations, ensuring uninterrupted compliance with aviation and industrial lighting standards. Utilizing advanced toroidal current sensing technology, the SCR630T provides robust electrical isolation from the monitored lighting circuit while enabling simultaneous monitoring of multiple lamp lines. The device can track up to four side lights or four beacon lamps, making it ideal for airports, communication towers, and industrial facilities. When a lamp failure occurs—indicated by a significant current drop—the SCR630T activates a fixed 6-second trip delay to prevent nuisance alarms. After this delay, an onboard LED illuminates and two alarm outputs energize: an isolated 10A SPDT relay contact and a 1A solid-state line voltage alarm output. These outputs support remote monitoring or activation of spare lamps. The alarm status and LED reset automatically when failed lamps are replaced and current returns to nominal levels or when input voltage is removed. User-friendly configuration is achieved through switch-selectable options for lamp wattage (116W or 620W) and the number of operating lamps (1-4). The SCR630T operates reliably across a wide temperature range of -55°C to 65°C and mounts securely via two #6 screws. With input voltage tolerance of ±10% at 230VAC and 50/60Hz AC line frequency, this compact device (88.9 mm H x 63.5 mm W x 44.5 mm D) delivers essential monitoring capabilities for critical lighting infrastructure.
  • Monitors up to 4 incandescent side lights or beacon lamps
  • Fixed 6-second trip delay prevents nuisance alarms
  • Isolated 10A SPDT relay contact and 1A solid-state alarm output
  • Switch-selectable lamp wattage (116W or 620W) and lamp count (1-4)
  • Operates from -55°C to 65°C with ±10% voltage tolerance

Specifications

Brand Name
Littelfuse
Connection
Two #6 (M3.5 x 0.6) screws
Connection Type
Screw Terminal
Current Rating
10 A
Frequency
50/60 Hz
Mounting
Two #6 (M3.5 x 0.6) screws Mount
Mounting Type
Screw (2 x #6 screws)
Operating Temperature
-40 to 65 F
Operating Temperature, Maximum
65 F
Operating Temperature, Minimum
-40 F
Poles
SPDT
Series
SCR Series
Series
SCR
Size
88.9 mm (H) x 63.5 mm (W) x 44.5 mm (D)
Special Features
10Y WARR
Standard
CE/CSA
Sub Brand
SSAC
Voltage Rating
230 V AC
The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.

SCR430T

The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.
The PHS230A6 relay provides phase control protection with input voltage at 230 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.

PHS230A6

The PHS230A6 relay provides phase control protection with input voltage at 230 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.
The PCR Series of photo control is a combination of precision electronic circuitry, electromechanical output, and unique molded plastic housing. Designed and built to meet the demands of the most rigorous requirement of tower and obstruction lighting control, each unit is factory calibrated to meet FAA and FCC specifications. Electronic circuit, output contactor, and terminal block are all contained within front plastic housing. Edge support molded into the bottom edge of housing allows easy wiring of new and existing installations. Available with or without cast aluminum junction box. Operation: When the amount of light sensed falls below the actuation level for energization, the output relay energizes. Conversely, when the amount rises above the actuation level for de-energization, the output relay de-energizes.

PCR10

The PCR Series of photo control is a combination of precision electronic circuitry, electromechanical output, and unique molded plastic housing. Designed and built to meet the demands of the most rigorous requirement of tower and obstruction lighting control, each unit is factory calibrated to meet FAA and FCC specifications. Electronic circuit, output contactor, and terminal block are all contained within front plastic housing. Edge support molded into the bottom edge of housing allows easy wiring of new and existing installations. Available with or without cast aluminum junction box. Operation: When the amount of light sensed falls below the actuation level for energization, the output relay energizes. Conversely, when the amount rises above the actuation level for de-energization, the output relay de-energizes.
The SIR2B20A4 relay provides solid-state switching protection with input voltage from 90 to 150 V ac/dc and output voltage at 120 V ac.

SIR2B20A4

The SIR2B20A4 relay provides solid-state switching protection with input voltage from 90 to 150 V ac/dc and output voltage at 120 V ac.
The PHS120A6 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.

PHS120A6

The PHS120A6 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.
The PHS120A20 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 20 A; inrush of 200 A.

PHS120A20

The PHS120A20 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 20 A; inrush of 200 A.
The PHS120A10 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 10 A; inrush of 100 A.

PHS120A10

The PHS120A10 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 10 A; inrush of 100 A.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS127

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FS300 Series of solid-state flashers were specifically designed to operate lamp loads. Their two-terminal series connection feature makes installation easy. The high immunity to line noise and transients makes the FS300 Series ideal for moving vehicle applications. All solid-state construction means reliability and long life. The FS300 Series offers a factory fixed flash rate of 75 FPM or may be ordered with a fixed, custom flash rate ranging from 60 to 150 FPM. Operation: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS324

The FS300 Series of solid-state flashers were specifically designed to operate lamp loads. Their two-terminal series connection feature makes installation easy. The high immunity to line noise and transients makes the FS300 Series ideal for moving vehicle applications. All solid-state construction means reliability and long life. The FS300 Series offers a factory fixed flash rate of 75 FPM or may be ordered with a fixed, custom flash rate ranging from 60 to 150 FPM. Operation: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS126

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS146RC

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First) FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FA155-2

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First) FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

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.