1. A control device for a machine tool including a motor for driving a spindle, the control device comprising:
a current detection unit that detects a current driving the motor;
a storage unit that stores overheat temperature specified for the motor;
a temperature detection unit that detects temperature of the motor;
a time estimation unit that estimates, by using the temperature detected by the temperature detection unit and the overheat
temperature, time from when present estimation takes place until the motor reaches the overheat temperature, under a condition
in which the current detected by the current detection unit continuously passes through the motor; and
a provision unit that provides the time estimated by the time estimation unit.