Descrizione
General Information: Bimetallic thermal protectors are constructed to protect electrical equipment against sudden and abnormal temperature rises. Their operation is mainly based on the expansion and contraction of the sensing element contained within the housing (bimetallic foil). As the temperature rises, the surface of the foil with the greater coefficient of expansion begins to elongate: however, the natural extension of the foil is hindered by the part of the foil with the lower coefficient of expansion. The two surfaces therefore begin to contract, until the more sensitive part flexes the less sensitive one.
Contact opening: At this instant, the sensing element quickly flexes (quick snap), opening the contact and interrupting the power supply.
Contact restoration: When the temperature conditions prior to the danger threshold have been restored, the protector, taking advantage of the same principles listed above, but in reverse order, returns to close the contact, allowing the circuit to be energized.
NO (Normally Open) Contact In normally open contact applications, the process is reversed.
Typical applications: Electric motors, transformers, coils, audio-video amplifiers, home appliances, electronic boards (hard terminals), general electrical equipment.
Properties: High temperature sensitivity, with extremely fast switching times; uniform performance over time. Small size, with plastic housing complying with UL 94 V-0 standards.
