Aumov LV Ultramov Varistor Design Guide Page 11 Varistor Design Guide For DC & Automotive Applications

DC Application Varistor Design Guide 2015 Littelfuse DC Application Varistor Design Guide www.littelfuse.com LV UltraMOV Varistor Application Examples A variety of applications employ 12VDC-96VDC circuits, including telecom power, sensing, automation, control, and security systems. Transients on these lines can be caused by lightning interference, inductive spikes from power switching, and fast transients from induced power line fluctuations. For example, a relay switching on/off can cause a magnetic transient in the coil inductance, which produces a high voltage spike. Compared with the other clamping and crowbar technologies that are used for voltage suppression, varistor technology is still one of the most cost-effective ways to protect against high energy surges on these 12VDC-96VDC lines. LV UltraMOV Varistors are widely used in a number of application areas: Clamping Lightning-induced Transients in Power Supplies Inductive Load Switching Switching of inductive loads, such as those that occur with transformers, generators, motors and relays, can create transients up to hundreds of volts and amps, and can last as long as 400 milliseconds. LV UltraMOV Varistor Application Examples Most transients induced by nearby lightning strikes result in an electromagnetic disturbance on electrical and communication lines connected to electronic equipment. 10

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