Littelfuse CT1S30 - The CT Series combines a delay-on-make and delay-on-break time delay into one unit and may be used to control fan delays in heating and/or cooling equipment. The CT includes bypass circuitry to allow it to operate with cooling anticipators 3000 ohms. It is designed to operate in 24VAC control circuits. Several CT modules may be combined to provide sequencing on of any number of loads and sequencing off of the same loads, such as electric heating elements. Operation (Delay-on-Make/Delay-on-Break): Forced Air Heating or Air Conditioning (as shown): When the thermostat closes, the compressor relay is immediately energized. At the end of a fixed delay-on-make delay (T1), the fan relay is energized. When the thermostat opens, the compressor relay is de-energized and the delay-on-break delay is initiated. On completion of the fixed delay-on- break delay (T2) the fan relay is de-energized. If the thermostat is reclosed during the delay-on-break delay, the delay-on-break delay is reset and the fan relay remains energized. If the thermostat is closed when input voltage is applied, the delay-on-make delay (T1) begins as normal. Reset: Removing input voltage resets the output and time delays.
Littelfuse

CT1S30

Alternate Item Number: CT1S30

UPC: 079458991956

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Overview

The Littelfuse CT1S30 is a microcontroller-based time delay relay from the CT Series, engineered for precise control in HVAC systems. This compact, solid-state module combines both delay-on-make (T1) and delay-on-break (T2) functionality into a single unit, simplifying wiring and optimizing heating and cooling operations. Designed for 24VAC control circuits, the CT1S30 is ideal for managing fan delays, ensuring proper system sequencing in forced air heating and air conditioning systems. Its encapsulated construction provides inherent protection against shock, vibration, and humidity, with no moving parts to arc or wear out over time. The unit features bypass circuitry compatible with cooling anticipators rated at 3000 ohms or higher. Operation is straightforward: upon thermostat closure, the compressor relay energizes immediately, followed by a fixed delay-on-make (T1) before the fan relay is energized. When the thermostat opens, the compressor relay de-energizes, initiating a fixed delay-on-break (T2) before the fan relay de-energizes. If the thermostat recloses during the delay-on-break period, the delay is reset, and the fan relay remains energized. The CT Series offers interconnectability, allowing multiple CT modules to be combined for sequencing multiple loads, such as electric heating elements, both on and off. Key specifications include a 0.75A steady-state and 5A inrush output rating at 55°C, a voltage drop of approximately 1.25V, and a recycle time of ≤ 300ms. The unit operates within a wide temperature range of -40° to 70°C and features surface mount capability with a single #10 screw. Its dimensions are 50.8 mm (H) x 50.8 mm (W) x 30.7 mm (D), with 0.25 in. (6.35 mm) male quick connect terminals for termination.
  • Combines delay-on-make and delay-on-break functionality in one unit
  • Designed for 24VAC control circuits in HVAC systems
  • Solid-state, encapsulated construction for durability and protection
  • Interconnectable with other CT modules for multi-load sequencing
  • Operates in temperatures from -40°C to 70°C

Specifications

Brand Name
Littelfuse
Connection Type
Bypass circuitry for cooling anticipators 3000 ohms
Mounting
Surface mount with one #10 (M5 x 0.8) screw Mount
Number Of Poles
Surface mount with one #10 (M5 x 0.8) screw
Operating Temperature
-40 to 70 F
Operating Temperature, Maximum
70 F
Operating Temperature, Minimum
-40 F
Series
CT
Series
CT series
Special Features
10Y WARR
Standard
CE/UR/CSA
Sub Brand
SSAC
Voltage Rating
24VAC
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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.