Overload protection device for compressor motor

An overload protection device for a compressor motor, the overload protection device comprising:

• a base formed of an insulative material and comprising an inner space;
• a conductive terminal comprising an input terminal, an output terminal, and an intermediate terminal;
• an overload protection means placed in the inner space of the base;
• and
• a cover configured to cover the base,
• wherein the input terminal and the output terminal are at least partially embedded in the base and at least partially exposed inside the inner space, and
• the intermediate terminal is placed between the input terminal and the output terminal, the intermediate terminal being at least partially embedded in the base and at least partially exposed inside the inner space,
• wherein the overload protection means comprises:
• a resistance heating element capable of conducting electricity and having a predetermined electrical resistance value;
• a movable arm comprising a material having electrical conductivity and elastic resilience, the movable arm being placed above the resistance heating element and having a predetermined length, the movable arm extending in a length direction thereof;
• and
• a bimetal placed between the resistance heating element and the movable arm, the bimetal deforming in shape at a predetermined operating temperature and returning to an original shape thereof at a predetermined return temperature,
• wherein the resistance heating element is electrically connected to the output terminal at one end thereof and electrically connected to the intermediate terminal at the other end thereof, the resistance heating element generating heat when conducting electricity,
• wherein a lengthwise end of the movable arm forms a fixed contact that is fixed to and electrically connected to the intermediate terminal, and the other lengthwise end of the movable arm forms a movable contact configured to make contact with the input terminal and vary in position, such that the movable arm electrically connects the input terminal and the intermediate terminal,
• wherein electrical connection between the movable contact and the input terminal is broken and made in such a manner that when the bimetal deforms in shape at a temperature equal to or higher than the operating temperature, the movable contact is spaced apart from the input terminal, and when the bimetal returns to the original shape thereof at a temperature equal to or lower than the return temperature, the movable contact and the input terminal come into contact with each other;
• wherein the bimetal comprises a first bimetal and a second bimetal placed on the first bimetal,
• wherein the first bimetal is shaped like a disc curved downward in a concave dish shape and deforms and snaps at a first operating temperature in an upwardly protruding curved shape,
• wherein the second bimetal has a downwardly curved concave dish shape and deforms and snaps at a second operating temperature in an upwardly protruding curved shape,
• wherein the second operating temperature is higher than the first operating temperature.