MOTOR DRIVE APPARATUS

PROBLEM TO BE SOLVED: To obtain a motor drive apparatus which can perform an operation which is hard to stall and stop with reference to a large load change by a method wherein a detection current value is added to, or subtracted from, a stall-prevention set current value so as to be compared with a reference value, the correction value of a frequency is found, the correction value is subtracted from a frequency instruction value and the frequency instruction value is corrected. SOLUTION: The output current of an inverter main circuit 7 in a load operating state is detected by a current detection part 10. Its detection current value In is added to, or subtracted from, a stall-prevention set current value Is which is set by a stall- prevention current setter 13 by using an adder-subtracter 12. Then, by a comparator 14, the detection current value is compared with a reference value which is used to decide the change amount of a frequency, the reduction amount of the frequency, i.e., the correction value Δf of the frequency, is found, the correction value Δf is subtracted from a frequency instruction value by an adder-subtracter 15, and the frequency instruction value (f) is corrected. Thereby, an operation which is hard to stall and stop can be performed when the output current reaches a current limit level with reference to a large load change so as to operate a current limitation function.