| 摘要 |
PURPOSE:To provide a frost formation detector and a defrosting operation control device of simple construction and low cost by outputting an electric signal by means of a combination of a humidity sensor element and a resistor,which electric signal approximates an actual measurement value of frost formation from the steam in an arbitrary atmosphere per unit time at a temperature lower by a specified temperature than the temperature of said arbitrary atmosphere. CONSTITUTION:In a circuit which consists of a humidity sensor element 1 and resistors 2-4, when an alternating current of a constant amplitude is inputted to an A.C. input terminal square, the values of resistors 2-4 for the humidity sensor element 1 are set so that an output of an amplitude which corresponds to the amount of frost from the steam contained in an arbitrary atmosphere per unit time in an atmosphere at a temperature which is lower by a specified temperature than the temperature of the said atmosphere. Further, by supposing the surface of an outdoor heat exchanger as an atmosphere of the temperature which is lower by a specified temperature, it becomes possible to output a signal similar to the amount of frost formation on the outdoor heat exchanger per unit time to a frost formation detector, and when it is known by addition of said signals that the amount of frost formation has reached a specified value, signal of the start of defrosting is issued to control the defrosting operation.
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