Refrigerator thermostat controller and power switch - has test position accessed by clockwise rotation with knob removed with supply contacts closed and thermostat contacts open

摘要

The refrigerator thermostatic control consists of two sets of electrical contacts. One set is normally operated automatically by a lever linked mechanically to a thermostat capsule and a set of contacts providing supply current to a defrosting resistor is operated manually by a rotating cam. The rotating cam has two lugs one flat with a ramp edge and one axial. When the cam is rotated anticlockwise the defrosting contacts are opened by the axial lug and when rotated clockwise the normal contacts are opened by the flat lug. When the normal contacts are opened the supply contacts are closed and when the supply contacts are opened the supply contacts are closed and when the supply contacts are open the normal contacts are controlled by the action of the thermostat. The edge of the cam is profiled and has a cam follower which exerts a variable counter force on the control lever and thermostat capsule. The control knob mounted on the shaft of the rotating cam has grooves with end stops on the face of the housing which limit the rotation of the knob so that the cam follower remains on the control profile in one sense and in the opposite sense stops when the supply contacts are opened. When the knob is removed and the cam turned clockwise the normal contacts are opened. This is useful for testing purposes during manufacture and repair.