Performance calculation for tunnel boring machine motors

The performance of a tunnel boring machine (TBM) is dependent upon the mine power distribution system providing adequate voltage. The voltage at the motors may be calculated using a standard computer load flow program. These calculated voltages are compared to measured voltages in the tunnel. The classical induction motor equivalent circuit is used to calculate the torque output for a given voltage input. Current and speed versus horsepower curves are developed from the model and compared with motor test data. The motor modeling results are used to adjust the simplified motor model in the load flow program. The results of the calculation are a torque versus distance curve that summarizes the performance of the TBM. Using this method, the effects of changes in source voltage, transformer taps, cable size and other factors on machine performance can be evaluated