Torsional Short Circuit Torque

Torsional Excitations Expressed in Equations

This option allows you to input the short circuit torques and other torsional excitations that can be expressed by computable equations for torsional time transient analysis. Although short circuit torque is the most common torsional excitation given in equations, it is NOT limited by the short circuit torques. Any time dependent excitation torque expressed in the following equation can be modeled as Type zero (0) in the input page.

The following input page shows the transient torques for a typical 2000 Hp, 4000V, 2 pole, 60 Hz motor. Please note that the 2-phase short circuit and 3-phase short circuit do not occur at the same time. They are listed simultaneously here only for reference purposes. The steady state driving torque and load torques are also entered in this form. The steady state driving torque and load torques have effects on the initial conditions (acceleration).

Other types of excitations have not been implemented and will be added in the near future.

The torque and horsepower are related by:

Torsional Excitation data from external data file

This option allows you to input the time dependent torsional excitations from the data files. The data stored in data files are ASCII free format file containing two columns, separated by spaces. One is time in seconds and the other is excitation as shown below:

0 0

0.001 50

0.002 100

0.005 900

0.010 7000

Be careful to avoid any strange characters or unusual formats in this ASCII data file.

Linear interpolation will be used for sudden changes in excitation, such as step function, triangular shapes, etc… You may specify the starting time to include this excitation in the analysis. If the Periodic Excitation is checked, then the excitation will become periodic and it will repeat when the time is end. The maximum time (time at the last point) is the period. If the Periodic Excitation is NOT checked, the excitation will be a constant when the time exceeds the last point. No extrapolation will be used. Any time larger than the given time in the data file, the last point (torque) will be used when time is greater than the last point.

See other Torsional/Axial Data Torsional/Axial Data.