| 摘要 |
PROBLEM TO BE SOLVED: To detect the correct start/stop timing of defrost operation by eliminating the influence of change in condition of heating operation or natural wind on the number of rotations of a fan. SOLUTION: To correctly detect change in the number of rotations of a fan motor caused by frost formation on fins of a heat exchanger, the following processing is performed: Firstly, the fan motor is driven in fixed voltage (ST11), and the driven-time rotational number is stored (ST12); secondary, the not-driven-time rotational number at a time where the fan motor is not driven is detected (ST13). When the not-driven- time rotational number is approximately zero (ST14-Y), the determination is made to be in a calm state, so that the driven-time rotational number is used as it is. When the not-driven-time rotational number is not approximately zero (ST14-N), the not- driven-time rotational number is stored (ST15) and the above processing is repeated by predetermined times. When the repetition is completed (ST10-Y), the driven-time rotational number is corrected by the not-driven-time rotational number (ST16), the mean value is calculated (ST17), the calculation result is decided as a final driven-time rotational number, a reference rotational number is compared to the driven rotational number, and then the determination is made about the defrost operation. COPYRIGHT: (C)2003,JPO
|
