Littelfuse TMOV and iTMOV Thermally Protected Varistors consist of radial leaded Metal Oxide Varistors (MOVs) with a thermally activated element that is designed to open in the event of overheating. The varistors integrated thermal element and appropriate enclosure design, help facilitate SPD module compliance to UL1449 for both cord-connected and permanently connected applications. These TMOV and iTMOV varistors offer quick thermal responses due to the close proximity of the integrated thermal element to the MOV body. The integrated configuration also offers lower inductance than most discrete solutions resulting in improved clamping performance to fast overvoltage transients.
The iTMOV varistor differs from the TMOV varistor by the inclusion of a third lead for the purpose of indicating that the MOV has been disconnected from the circuit. This lead facilitates connection to monitoring circuitry. These TMOV and iTMOV varistors are wave solderable, thus simplifying end product assembly by reducing the expense and rework associated with hand soldering operations. Typical applications include white goods, plug-in SPD, inverters, AC power meters, and AC line power supplies.