Littelfuse KRDS221 - 2X2 SINGLE SHOT W/RELAY
Littelfuse

KRDS221

UPC: 079458995046

Documents & Media
Specification Sheet

Contact for Pricing

Minimum Qty: 10

Multiplier: 10

*Contact for lower quantities*

Overview

The Littelfuse KRDS221 is a highly reliable and compact single shot time delay relay module, engineered for demanding industrial control applications. Measuring a mere 2 inches (50.8 mm) square, this module offers exceptional space-saving flexibility, making it an ideal choice for OEM applications where size and integration are critical. At its core, the KRDS221 features a sophisticated microcontroller-based timing circuit. This advanced technology ensures superior repeat accuracy, with specifications typically within +/- 0.5%, and factory calibration accuracy of +/- 5%. This precision is vital for applications requiring consistent and predictable timing sequences. The module's robust encapsulation provides excellent protection against environmental factors such as shock, vibration, and humidity, guaranteeing long-term operational stability even in harsh industrial settings. The single shot operation of the KRDS221 is designed for straightforward integration into control systems. Input voltage must be present before and during the timing cycle. Upon closure of the initiate switch (either momentary or maintained), the output relay energizes for a pre-determined interval. Once the delay period concludes, the output relay de-energizes. Importantly, any manipulation of the initiate switch during the timing sequence will not affect the established delay. The output will reliably energize if the initiate switch is closed at the moment input voltage is applied. Resetting the KRDS221 is achieved by opening the initiate switch after the time delay has completed, or by removing the input voltage, which simultaneously resets the timing and the output state. This predictable reset behavior simplifies system design and troubleshooting. Key features and benefits of the Littelfuse KRDS221 include: * **Compact, Low-Cost Design:** A 2-inch square footprint provides significant design flexibility for OEMs. * **Microcontroller-Based Timing:** Delivers exceptional repeat accuracy and stability for precise control. * **Isolated 10A SPDT Output Contacts:** Capable of controlling a wide range of AC or DC loads, offering versatility in system integration. * **Encapsulated Construction:** Protects against shock, vibration, and humidity for enhanced durability and longevity. This time delay relay is an excellent solution for automation, process control, machinery control, and any OEM application that demands reliable isolation, precise timing, and a long operational lifespan in a compact form factor. Littelfuse's commitment to quality and innovation ensures that the KRDS221 will perform dependably in critical control system applications.
  • Compact 2x2 inch (50.8mm square) design for OEM flexibility
  • Microcontroller-based timing circuit for excellent repeat accuracy (+/- 0.5%)
  • Isolated 10A SPDT output contacts for AC/DC load control
  • Encapsulated construction protects against shock, vibration, and humidity
  • Single shot operation with precise timing and reset functionality
RTXD Extractor Tool

6896057-1

RTXD Extractor Tool
RTXP 18

RK926011-BC

RTXP 18
Relay Accessories, Sockets & Clips, Printed Circuit Board, Phenolic, Printed Circuit Board, 6, Socket, Potter & Brumfield R10

1-1393143-3

Relay Accessories, Sockets & Clips, Printed Circuit Board, Phenolic, Printed Circuit Board, 6, Socket, Potter & Brumfield R10
Relay Accessories, Sockets & Clips, Solder, Polyester, Printed Circuit Board, 2, Socket, Potter & Brumfield R10

1-1393143-6

Relay Accessories, Sockets & Clips, Solder, Polyester, Printed Circuit Board, 2, Socket, Potter & Brumfield R10
Power supply for DIN-rail

PS-60

Power supply for DIN-rail
IP67 SCP-X Extreme Environment Series Power Supply. Double Stacked, Output Power 2 x 100W, Output Voltage 24 Vdc, Output Current 7.6 A total, 3.8 A per pair

SCP102D24X-C02

IP67 SCP-X Extreme Environment Series Power Supply. Double Stacked, Output Power 2 x 100W, Output Voltage 24 Vdc, Output Current 7.6 A total, 3.8 A per pair

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.