Limitor

The current and temperature limiter Y is used wherever, on one hand, protection against overtemperatures as well as against overcurrents is required, and on the other hand, automatic switch on function of the device to be protected - subsequent to a follow-on cooling down period - is prohibited or undesired.

Function

The current and temperature limiter Y operates current sensitiv. Temperature detection is realized by bimetal disk which was first dimensioned in accordance with the required cut-off temperature. When this fixed cut-off temperature TA is reached, this bimetal disk will snap , breaking a contact system and thereby interrupting the electric circuit of the device to be protected.

Current sensitivity

In the case of an obvious current increase (blocking current or short-circuit current) a resistor, lying in series with the contact system inside the limiter, heats the bimetal disk to its cut-off temperature TA very quickly. When this cut-off temperature TA is reached, the bimetal disk will snaps suddenly and breaks the contacts of the switch. To get an optimal adjustment in accordance to the application there are wide range of resistor values are available .

Self-holding function

By means of a resistor heat is generated by the supply voltage applied after breaking the contact. This heat prevents any decrease in temperature below the value necessary for the cut-in temperature TE. In this was, the switch will keep its contact open, irrespective of its ambient temperature. Cut-in of the switch, and thus closing the circuit, will be possible only after disconnection from the supply voltage.