Single-function relays produced by Littelfuse respond to temperature or voltage changes to control HVAC units, lighting fixtures, and fans. Our solid-state relays have residential and industrial applications, acting as on–off switches for current. The performance of each temperature-controlled or voltage-controlled relay will depend on its placement. Please consult with a Littelfuse expert to ensure you choose the correct solution and receive optimized results from the single-function relay you select.

 

Littelfuse Alternating Relays

Use Littelfuse alternating relays to optimize electrical loads by equalizing the run time of two or more electric motors. These relays often get used to control and balance the flow of electricity to active pumps and compressors. Doing so prevents equipment failure and maximizes equipment life.

Littelfuse Current Monitoring Relays Transducers

Littelfuse current and load monitoring relays, sensors, and transducers are the ideal solution for monitoring loads. These products protect against equipment damage from irregularities and predict risks before they cause problems. They monitor input and output currents passing through circuits for warning signs such as overvoltage or undervoltage, overcurrent or undercurrent, phase issues, and other indicators. Each protective unit provides an applicable response. Littelfuse offers...

Littelfuse Flashers & Tower Lighting Controls

Littelfuse designs and manufactures flashers and tower lighting controls for a variety of industrial applications including communication towers, smokestacks, cooling towers, tall buildings, bridges, and utility towers. These navigation lighting control solutions include obstruction lighting controls, solid-state sequencing controls, LED beacon lamp alarm relays, and a selection of flashers for inductive, incandescent, and resistive loads. This broad portfolio also includes the photo control...

Littelfuse Intrinsically Safe Relays

Littelfuse intrinsically safe relays are UL 913 listed as associated apparatuses for interfacing between hazardous and nonhazardous areas. These high-quality products protect hazardous location circuits and are core components for intrinsically safe applications. The ISS-105 series is designed as a "smart" five-channel relay and pump controller, which can be configured for pump-up or pump-down applications. The ISS-102 offers two LEDs for visual indication of relay...

Littelfuse Proof Relays

Littelfuse proof relays are used to verify that current is flowing as intended and are the ideal solution for monitoring and processing input parameters. These high-quality products interpret incoming data and provide the appropriate output response such as visual indication, setting change, or warning alarms. The Littelfuse proof relays are typically used to interlock fans, compressors, motors, heating elements, and other devices. The LSR and LSRX relays are self-powered load sensors.

Littelfuse Pump Controls & Liquid Level Controls

Littelfuse pump controls and liquid level controls are designed to detect abnormalities in pumping systems and ensure they are operating at the required flow rate. This product line consists of two different types of control units: 1. seal leak detectors that identify pump seal leaks and motor overheating on submersible pumps, and 2. liquid level controls that control liquid pumping operations in a pump-up or pump-down application. These products are invaluable for maintaining...

Littelfuse Single-Function Relays

Littelfuse single function relays are designed for the protection, control and/or monitoring of generators and other devices. These high-quality, single function relays are used for a variety of industrial applications including solid-state switching protection, dedicated temperature control, and phase control adjustment. The simplified controls perform a specific function such as changing lamp intensity, varying the speed of a motor, or managing the temperature of a heate

Littelfuse Time-Delay Relays

Littelfuse manufactures a variety of time delay relays designed to control power to different types of electrical loads. These time delay relays include multi-function, on-delay, delay-on-make, delay-on-break, single shot, interval, recycle, percentage, dual-function, HVAC, and coin vending. The multi-function relays provide the option of choosing among functions and time delay ranges. The electro-mechanical relays offer a number of different functions and ensure isolation between input and...

Littelfuse Voltage-Monitoring Relays

Littelfuse offers a variety of voltage monitoring relays that are designed to protect industrial equipment against voltage fault conditions. These single-phase and three-phase system relays provide highly accurate and precise voltage measurements that activate a response to abnormal operating conditions in order to prevent harmful damage to equipment. The voltage monitoring relays not only detect under-voltages and over-voltages, they also detect related issues such as phase imbalance, phase loss, and phase sequence.