| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the breakage of a device caused by a setting error and also to prevent excessive derating by enabling a protector to automatically compute the amount of derating according to a carrier frequency, a DC voltage, ambient temperature, etc. <P>SOLUTION: This overload protector divides a subtracted value which is obtained by subtracting a value where a noise margin is added to a device rated current from an output current of an inverter device by means of a subtractor 1, through a derating amount limitter 7 which is obtained from a carrier overload setting correction amount calculated by a carrier overload setting correction amount operating part 6. The protector compares the integral value of the subtractor with a trip reference value set by a parameter by means of a comparator 5, and generates an overload fault output in the case that the integral value is over the trip reference value, and calculates the carrier overload setting correction amount by a specified calculating formula. <P>COPYRIGHT: (C)2007,JPO&INPIT |
