Littelfuse TDR4A33 - The TDR Series of time-delay relays are comprised of digital circuitry and an isolated, 10A relay output. The ON and OFF delays are selected by means of two, ten position binary switches, which allow the setting of the desired delay to be precise every time. Operation (Recycling - ON Time First): Upon application of input voltage, the green LED glows, the output relay is energized, the red LED glows, and the T1 ON time begins. At the end of the ON time, the output de-energizes, the red LED turns OFF and the T2, OFF time begins. At the end of the OFF time, the output relay energizes and the cycle repeats as long as input voltage is applied. Reset: Removing input voltage resets the output and time delays, and returns the sequence to the first delay. Operation (Recycling - OFF Time First): Upon application of input voltage, the green LED glows, the T1 OFF time begins, the load is OFF. At the end of the OFF time, the T2 ON time begins, the load energizes, and the red LED glows. At the end of the ON time the load de-energizes and the red LED turns OFF. The cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to the OFF time.
Littelfuse

TDR4A33

Alternate Item Number: TDR4A33

UPC: 079458999853


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Overview

The Littelfuse TDR4A33 is a dedicated, recycling time-delay relay featuring advanced digital integrated circuitry for precise ON and OFF timing control. This model offers an isolated 10A electromechanical relay output, capable of handling resistive loads up to 10A at 120/240VAC and 28VDC, or 1/3 hp at 120/240VAC. The TDR4A33 provides exceptional timing accuracy with a repeat accuracy of ±0.1% or 20ms (whichever is greater) and setting accuracy of ±2% or 50ms (whichever is greater). Time delays are precisely set using two ten-position binary switches, allowing for granular adjustments across multiple ranges: 0.1s to 102.3s in 0.1s increments, 1s to 1023s in 1s increments, and 10s to 10,230s in 10s increments. The TDR4A33 supports two distinct recycling operational modes: ON Time First and OFF Time First. In the 'ON Time First' mode, upon application of input voltage, the green LED indicates power, the output relay energizes, the red LED illuminates, and the T1 ON time begins. Upon completion of the ON time, the output de-energizes, the red LED turns off, and the T2 OFF time commences. The cycle repeats until input voltage is removed. In the 'OFF Time First' mode, the green LED indicates power, the T1 OFF time starts with the load de-energized, and the red LED is off. After the OFF time, the T2 ON time begins, energizing the load and illuminating the red LED. This cycle also repeats until input voltage is removed. Removing input voltage resets both the output and the time delays, returning the sequence to its initial state. Key features include microcontroller-based design for reliability, isolated output contacts for versatile AC or DC load control, and LED indicators for visual status feedback. The relay has a mechanical life of 1 x 10^7 cycles and an electrical life of 1 x 10^6 cycles. It is designed for plug-in socket mounting with an octal 8-pin termination and operates within a temperature range of -20°C to 65°C. This time-delay relay is ideal for automation, process control, and machinery applications requiring repeatable and accurate cyclical timing.
  • Digital integrated circuitry for precise timing
  • Isolated 10A electromechanical relay output
  • Two recycling modes: ON Time First & OFF Time First
  • DIP switch adjustment for precise ON/OFF delay settings
  • LED indicators for status feedback (Green: Input, Red: Output)

Specifications

Brand Name
Littelfuse
Mounting
Plug-in socket Mount
Number Of Poles
Plug-in socket
Operating Temperature
-20 to 60 F
Operating Temperature, Maximum
60 F
Operating Temperature, Minimum
-20 F
Special Features
10Y WARR
Standard
CE/UR/CSA
Sub Brand
SSAC
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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.