Abstract
The thermo-model block diagram of induction motors for the temperature rise and time characteristics of the continuous operation are introduced. Numerical values of each constants for block diagram are calculated.
The thermo-model block diagram has two inputs and two outputs. Two inputs are copper loss and iron loss, and two outputs are temperature rise characteristics of coil and iron core. Copper loss is calculated from the equivalent circuit of induction motor and iron loss is measured. When induction motor is operated intermittently, copper loss is also changed intermittently and iron loss is changed when the applied voltage is varied.
If copper loss and iron loss depending on intermittent operation are applied to input points of the block diagram, then the temperature rise characteristics of coil for intermittent operation are derived.
The errors calculated by these method are within about 2°C for temperature rise and 2 minutes for time constant.
