Motor control device

A motor control device that controls an induction motor driving a spindle of a machine tool, the motor control device comprising:

• a spindle control unit that controls a rotational position or rotational speed of the spindle, and a secondary magnetic flux of the induction motor in accordance with an operation command based on an operation program of the machine tool;
• an advance detection unit that pre-reads the operation program, and detects a change in the operation command requiring to increase the secondary magnetic flux of the induction motor in advance;
• an advance change unit that causes the secondary magnetic flux of the induction motor to increase prior to a change in the operation command in the spindle control unit, in a case of a change in the operation command being detected by the advance detection unit;
• a setting unit that sets, as a setting value, a change timing at which to increase the secondary magnetic flux of induction motor prior to a change of the operation command;
• and
• a storage unit that stores a time constant related to a change in the secondary magnetic flux of the induction motor,
• wherein the setting unit sets, as the setting value, the change timing based on the time constant stored in the storage unit,
• wherein the setting unit sets the setting value to a time that is at least 3-times the time constant, and
• wherein the advance change unit causes the secondary magnetic flux of the induction motor to increase based on the setting value set by the setting unit.