Controlling method and apparatus for actuating induction motor

A control method for controlling an induction motor with an actuation control apparatus for the induction motor comprising:

• phase windings of a Y-connection type each having one end connected to an electric power supply terminal and the other end to a neutral point;
• a first and a second split windings for each said phase windings, which are formed by splitting each of said phase windings at a predetermined split ratio based on a number of turns of winding, split points of said first and second split windings being respectively connected to a first and second intermediate terminals;
• a first changeover switch connected between said first intermediate terminals of each said phase windings and said electric power supply terminal;
• a second changeover switch connected between said first and second intermediate terminals of each said phase winding;
• a third changeover switch connected between said second intermediate terminals of said second split windings;
• and a switching control means for on-off controlling said first, second and third switches based on a rotational speed of said induction motor;
• said controlling method comprising the steps of:
• turning on said second changeover switch and turning off said first and third changeover switches in a case where the rotational speed of the induction motor is in a low speed region;
• turning on said third changeover switch and turning off said first and second changeover switches in a case where the rotational speed of the induction motor is in a middle speed region;
• and
• turning on said first changeover switch and turning off said second and third changeover switches in a case where the rotational speed of the induction motor is in a high speed region.

A control method for controlling an induction motor with an actuation control apparatus for the induction motor comprising:

• phase windings of a Y-connection type each having one end connected to an electric power supply terminal and the other end to a neutral point;
• a first and a second split windings for each said phase windings, which are formed by splitting each of said phase windings at a predetermined split ration based on a number of turns of winding, split points of said first and second split windings being respectively connected to a first and second intermediate terminals;
• a first changeover switch connected between said first intermediate terminals of each said phase windings and said electric power supply terminals;
• a second changeover switch connected between said first and second intermediate terminals of each said phase winding;
• a third changeover switch connected between said second intermediate terminals of said second split windings;
• and a switching control means for on-off controlling said first, second and third switches based on a rotational speed of said induction motor;
• said controlling method comprising the steps of:
• turning on said second changeover switch and turning off said first and third changeover switches in a case where the rotational speed of the induction motor is in a low speed region;
• turning on said first changeover switch and turning off said second and third changeover switches in a case where the rotational speed of the induction motor is in a middle speed region;
• and
• turning on said third changeover switch and turning off said first and second changeover switches in a case where the rotational speed of the induction motor is in a high speed region.