Method and Device for Monitoring and Electrical Heating Apparatus

A method for monitoring an electrical heating apparatus having an electrical heating element, comprising:

• arranging a sensor to measure a measured value that depends upon a resistance or inductance of the electrical heating element;
• connecting the sensor to a monitoring device;
• measuring an actual measured value that depends upon a resistance or inductance of the electrical heating element;
• comparing the actual measured value to a predetermined comparison value;
• and
• determining if a fault exists based on the comparison between the actual measured value and the predetermined comparison value.

A plastic injection molding machine, comprising:

• a granulate hopper that holds a granulate plastic material;
• a screw drive that receives and conveys the granulate plastic material;
• an electrical heating apparatus arranged along the screw drive, wherein the electrical heating apparatus has a heating element, comprising:
• a sensor that measures a value dependant on the resistance or inductance of the electrical heating element, and
• a monitoring device connected to the sensor that compares an actual measured value from the sensor to a predetermined comparison value and determines if a fault exists based on the comparison between the actual measured value and the predetermined comparison value;
• an injection unit having an injection piston;
• and
• a linear drive unit connected to the injection piston;