PURPOSE: To attain an inexpensive weight detector, by connecting a vector control inverter, which divides a primary current to exciting current components and torque current components and gives them, to the primary side of an induction motor which is used for moving an object.
CONSTITUTION: A three-phase full-wave rectifying circuit 3 and a vector control inverter 4 are connected between a three-phase AC power source 1 and a three- phase induction motor 2. A velocity detector 8 generates the number of pulses proportional to the rotative velocity of the motor 2, and a converting circuit 9 converts it to an analog signal. A subtractor 10 subtracts the output of the converting circuit 9 from the output of a velocity setter, and an error amplifying circuit 11 performs the proportional integral operation of the output of the subtractor 10. This output becomes torque current components it and is sent to a vector calculating circuit 12 and a slip angle frequency output circuit 13. An exciting current setter 16 gives an exciting current signal im of the motor 2, and its phase is 90° behind the signal it in the circuit 12.
OOHASHI KOUJI
HONMA SATOSHI
FUJITA SHIYOU
HAYASHI KAZUMI
IBORI SATOSHI
