Numerical control device provided with heat radiation characteristic estimation part

A numerical control device which is provided at a motor drive system which is provided with a cooling device and drives at least one motor, said numerical control device comprising:

• a processor, wherein the processor comprises:
• a temperature acquisition part which acquires a temperature of component elements at a motor part of said motor drive system from a temperature detector which is set in the motor drive system,
• an ambient temperature acquisition part which acquires an ambient temperature of the motor part of the motor drive system from a temperature detector which is set at the motor drive system,
• an input energy acquisition part which acquires an input energy to the component elements,
• an output energy acquisition part which acquires an output energy from the component elements,
• a heat radiation characteristic estimation part which estimates a heat radiation characteristic of the component elements from the temperature of the component elements, the ambient temperature, the input energy, and the output energy, and
• a heat radiation characteristic outputting part which outputs the estimated heat radiation characteristic of the component elements as a normal/abnormal judgment signal of the cooling device wherein
• the numerical control device is configured to monitor an uptime and a downtime of the cooling device based on the normal/abnormal judgment signal,
• wherein said heat radiation characteristic estimation part subtracts a value for heat energy of said component elements which is calculated from the temperature of said component elements and heat capacity from loss energy of said component elements which is calculated by subtracting said output energy from said input energy to thereby calculate an amount of heat radiated from said component elements and divides said amount of heat radiated by a temperature difference of a temperature of said component elements and a temperature of said ambient temperature so as to calculate a heat radiation characteristic of said component elements.