Thermal mechanism with ambient compensating bimetal providing trip force

In a thermal protective mechanism having trippable means operable in response to an electrical overload condition for disconnecting a load device from an electrical power supply source, the improvement comprising:

• electrothermal responsive means;
• ambient temperature compensating means;
• preloading means including said ambient temperature compensating means for preloading said electrothermal responsive means which allows movement of said preloading means in response to an overload condition;
• and said electrothermal responsive means being responsive to an overload condition to relieve some of said preloading whereby said ambient temperature compensating means provides the force for moving said preloading means whereby said preloading means causes operation of said tripable means.

In a thermal protective mechanism having trippable means operable in response to an over-thermal condition for protecting a load device supplied from an energy source, the improvement comprising:

• thermal responsive means;
• ambient temperature responsive means;
• preloading means jointly and oppositely preloading said thermal responsive means and said ambient temperature responsive means such that when said thermal responsive means responds to an over-thermal condition to reduce the preload thereon, said ambient temperature responsive means provides the moving force for actuating said preloading means;
• and means responsive to said actuation of said preloading means under said over-thermal condition for tripping said trippable means.