PASSIVE SOLUTIONS

Devices Protect Electric Motors and Transformers from Damage

The Raychem PolySwitch LVR range of resettable circuit protection devices from Tyco Electronics are designed to protect the electric motors and transformers used in commercial and home appliances. The series can be used to help guard against failures caused by mechanical overloads, overheating, motor stalls, lost neutral and other potentially damaging conditions.



The family includes components that are rated for line voltages of 120VAC and 240VAC and for operating currents of up to 2A at 20°C. They offer low resistance, fast time to trip, a low profile and resettable functionality. These key attributes not only help circuit designers provide safe and dependable end products, but also assist in compliance with regulatory agency requirements and reduction of warranty repair costs.

PolySwitch devices are Polymeric Positive Thermal Coefficient (PPTC) components which, unlike single use fuses, do not require replacement after a fault event. When the over current condition is eliminated and power has been removed, the circuit is restored to normal operating condition. Compared to bimetal breakers, the LVR series therefore offer greater flexibility, longer lifespan and better ElectroMagnetic Interference (EMI) characteristics.

The PolySwitch LVR devices’ resettable functionality and latching attributes make them a reliable, costeffective circuit protection solution for both intermittent and continuous operation motor applications.



PPTC operation can also help to prevent damage in situations where a significant rise in temperature may be accompanied by only a slight increase in current draw. When installed on the primary side of a transformer circuit, in proximity to heatgenerating components such as magnetics, Field Effect Transistors (FETs) or power resistors, PolySwitch LVR devices help to provide both over current and over temperature protection within a single component. Such integrated protection can help cut down on space requirements for the overall protection implementation and reduce assembly costs accordingly.

These RoHS compliant devices conform to the UL 1434 standard and are compatible with lead free solders and high volume assembly processes.

Features/Benefits

• Resettable fuses for line voltage applications
• Over current and over temperature protection in a single device
• Helps reducing board space and assembly cost
• Helps reducing repair and replacement cost
• Fast time to trip helps reduce current generated heat in vulnerable components
• Help reduce nuisance tripping
• Latching device
• Compliant with UL 1434 safety standards

Applications

• Domestic appliances
• Continuous operation motors
• Intermittent operation motors
• Transformers
• Power supplies
• Fans and blowers
• Electronic controllers

Note: Raychem, PolySwitch, TE logo and Tyco are trademarks.

For further information, including the LVR Datasheet and LVR Technical Brief, please click here