Thermally responsive switch

A thermally responsive switch which is used to interrupt AC current flowing into an electric motor provided in a hermetic electric compressor, the switch comprising:

• a hermetic container including a metal housing and a header plate hermetically secured to an open end of the housing, the housing being formed into a cylindrical shape and having a bottom;
• a conductive terminal pin inserted through a through hole formed through the header plate and hermetically fixed in the through hole by an electrically insulating filler;
• a conductive pin inserted through a through hole formed through the bottom of the housing and hermetically fixed in the through hole by the electrically insulating filler;
• a thermally responsive plate having one of two ends conductively connected and fixed to the conductive terminal pin in the hermetic container, the thermally responsive plate being formed into a dish shape by drawing so as to reverse a direction of curvature thereof at a predetermined temperature;
• a movable contact secured to the other end of the thermally responsive plate;
• and
• a fixed contact fixed via an electrical conductor to the terminal pin in the container, the conductor having a fuse part and a heater, the fixed contact constituting a pair of switching contacts together with the movable contact,
• wherein the fixed contact is fixed to an electrically insulating ceramic member disposed between the container and the fixed contact;
• the ceramic member is disposed so as to be movable axially relative to the terminal pin in the container;
• and
• the housing includes a bottom surface further including both lengthwise ends between which the conductive pin is interposed, said both ends of the bottom surface of the housing being deformed axially relative to the conductive pin from an initial state, whereby an operating temperature of the thermally responsive switch is calibratable.