Heat Protector

Abstract

The central portion of a movable plate 40 is cut into a U shape to form a tongue 43 provided along the longitudinal axis of the movable plate 40, the tongue 43 is brought into close contact with an upper electrode face 31 of a heating resistor 30, a lower electrode face 32 of the heating resistor 30 is brought into contact with a fixed plate 10, and portions of the movable plate 40 located on both sides of a cut 46 operate as an elastic arm 47.

Description

technical field [0001] The present invention relates to a thermal protector incorporated in transformers, motors and the like. More particularly, it relates to a self-sustaining type thermal protector combined with a heating resistor composed of PTC (Positive Temperature Coefficient) to maintain an open state by heat generated by the heating resistor. Background technique [0002] There has hitherto been proposed a thermal protection resistor in which a PTC element such as a positive thermistor is added as a heating resistor to keep an open state by heat generated by the heating resistor. [0003] Figure 12 shows a thermal protector of the type proposed in Japanese Patent Application 7-282701. [0004] In this kind of thermal protector, the load current flows in this order or in the opposite order: terminal a for connecting with the outside→bimetal b→movable contact c→fixed contact d→fixed electrode e→ Terminal f for external connections. [0005] When the temperature of...

AI Technical Summary

Problems solved by technology

In conventional thermal protectors, the surface on the highly extended side of the bimetal b is in contact with the resistive surface of the thermistor g, and the stability of the electrical contact between the bimetal b and the thermistor g is insufficient

Therefore, there is a possibility that an appropriate heating current cannot flow through the thermistor g after the bimetal b is reversed

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