New PolySwitch™ Device Helps Protect Electric Motors and Transformers from Overcurrent and Overtemperature Damage

Feb. 28, 2007
Raychem Circuit Protection, a business unit of Tyco Electronics, has announced the introduction of its PolySwitch™ LVR series of resettable circuit protection devices. PolySwitch LVR devices help protect electric motors and transformers used in commercial and home appliances from failures caused by mechanical overloads, overheating, stall, lost neutral and other potentially damaging conditions. The PolySwitch LVR series includes components that are rated for line voltages of 120 VAC and 240 VAC, for up to 2A of operating current at 20°C. They offer low resistance, fast time-to-trip, a low profile, and resettable functionality to help circuit designers provide a safe and dependable product, comply with regulatory agency requirements, and reduce warranty repair costs. “The increasing sophistication and complexity of home and professional grade appliances is driving the need for more rugged and reliable resettable circuit protection devices,” said Faraz Hassan, industrial/appliance marketing manager for Raychem Circuit Protection products. “When used in line voltage installations, PolySwitch LVR devices can help reduce warranty returns resulting from motor failure – in a simple and cost-effective manner.” Unlike single-use fuses, PolySwitch devices do not require replacement after a fault event. After the overcurrent condition is eliminated and power has been removed, the circuit is restored to normal operating condition. Compared to bimetal breakers, they offer greater flexibility, longer lifespan, and lower electromagnetic interference (EMI). The PolySwitch LVR devices’ resettable functionality and latching attributes make them a reliable, cost-effective circuit protection solution for both intermittent and continuous-operation motor applications. PolySwitch LVR devices also help prevent damage where faults may cause a rise in temperature with only a slight increase in current draw. When installed on the primary side of a transformer circuit, in proximity to heat-generating components such as magnetics, field-effect transistors (FETs), or power resistors, the PolySwitch LVR device helps provide both overcurrent and overtemperature protection with a single installed component. The RoHS-compliant devices are widely used and are compliant with the UL 1434 standard, and are compatible with lead-free solders and high-volume assembly processes.