| 摘要 |
PURPOSE:To execute adequate overload protection for a power apparatus other than that in which temperature rise is proportional to the square of current by judging operation and non-operation using a function of the current value for simulating current vs. temperature rise characteristic and a value to be added obtained from the value before the current time being held in the inside. CONSTITUTION:A processing step 4 is related to an initializing means. In the processing steps 5-1 to 5-4, a value of the function f (I) of the current value I is computed. In the processing step 5-5, a value Sn to be added is computed depending on the equation (in the equation, K is a constant, 0<K<<1, Sn 1 is the value added before the current time). Subsequently, judging is made in the processing step 6 using the value Sn to be added. When Sn is larger than the predetermined value, an output e3 is generated in the processing step 7 and thereafter the sequence returns to the processing step 5-1. Thereby, the apparatus can be protected adequately depending on the allowable overload capability. |
