SimPhase IMC Program calculates the steady-state conditions (slip, speed, powers, etc.) of a three-phase induction motor for any combination of load torque and stator voltage.
The IMC program can also do calculations for motors with variable frequency drive (VFD) speed controls. You can ask for motor conditions at any speed.
The IMC Program requires that you define the load torque as a function of the speed (like it is done in a motor starting program).
Here is a load torque (expressed in percentage of motor’s full-load torque) defined as a function of the speed w (w is in per unit) using following equation:
load torque = 40 ⋅ (1 – w)3 + 85 ⋅ w2
Following image shows the plotting of the torque-speed characteristic of a motor (at a specific voltage) and the torque-speed characteristic of the load torque (as defined above). The intersection is the steady-state operating point.
Following image shows the results presented by the SimPhase Induction Motor Calculations (IMC) Program.
There is a licensed version of the IMC program.
There is also a free version of the IMC program. It has most features of the licensed version but the calculations are limited to three-phase induction motors rated 25 HP or less and without speed controls. You can use the free version for as long as you want. There is no time limit.
The IMC program can handle 50 Hz and 60 Hz three-phase induction motors.