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Packaged Rooftop Systems

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Motor Starters

Reliable fan and compressor motor starters help ensure HVAC system efficiency and consistent indoor climate control. Electronic components made by Littelfuse can boost starter performance. Our solutions include motor start capacitors, mechanical relays, contactors, and overload relays. We also supply current transformers to provide ground fault protection and earth fault relays for extra safety.

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Side-by-side rooftop HVAC units have white air intake fan grille

VFD Motors

HVAC fans and compressors use variable frequency drive (VFD) motors. Ensuring the ac motors speed up and slow down predictably, safely, and efficiently prolongs equipment life. Littelfuse offers many electronic components to achieve that goal, including power bridges for current switching, transformers for ground fault protection, and motor protection relays technicians can monitor via smartphone.

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Enabling Peak System Efficiency

Success Stories

Enabling Peak System Efficiency

A rooftop unit manufacturer was able to significantly reduce wasted energy by using customdesigned temperature sensors on the refrigerant pipes to control the defrost cycle of a heat pump. The sensors provided fast thermal response and helped reduce energy consumption.

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Helping to Maximize Energy Efficiencies

A delay-on-break timer monitors the system run time and determines how long the delay-on-break time delay should be. The longer the system runs, the longer the timing, the longer the fan runs. This custom solution, developed for a HVAC customer, maximizes the system’s heating and cooling by pulling as much conditioned air out of the duct work as possible making the system more efficient and reducing energy costs.

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Protects Against Accidental Manual Override

Multiple large OEM companies requested a customized three-phase voltage monitor without a manual reset option from the manufacturer to protect what’s inside their refrigeration racks. This forced a time-delayed restart by eliminating the possibility of the rack accidentally waiting on a manual reset.

Reducing Installation Time with Pre-Assembled Fuse Holders

A rooftop unit manufacturer was able to significantly reduce installation time by attaching the leads to the fuse holder. By utilizing pre-assembled 571 (standard) and 572 (snap-mount) panel-mount fuse holders, Littelfuse included a KLK 5 A 600 V ac fuse, 150 °C #12 to #18 wire and 150 °C heat-shrink tubing to help streamline assembly.

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Simplifying Tightening Process to Help Eliminate Assembly Errors

A major OEM approached Littelfuse indicating that they were having challenges with their installation tightening processes. Littelfuse designed a hex-screw head that would be better suited for their automated assembly, simplifying the tightening process and reducing assembly errors.