**CRITERIA—0% Torque Load; thus, 0 N.m**

**Figure 16.** (**a**) Voltage supply under no-load; (**b**) line currents under no-load.

**Figure 17.** (**a**) Electromagnetic torque under no-load; (**b**) electromagnetic torque vs speed under no-load.

**Figure 18.** Speed under no load.

The supply stays the same because no impedances exist at the source in this simulation. Figure 19a–c illustrates that the steady-state reached approximately 0.15 s later than with no load. This was expected because of the increase in the load.

As seen in Figure 19a, the amplitude was not affected by the higher magnitude of the load. Therefore, the conclusion can be drawn that the machine current is only a function of the machine's parameters.

As seen in Figure 20, the optimal point is at a lower speed than with no load.

As seen previously, as the loading increases, it takes longer for the steady-state to be achieved. At a full load (100% torque load), reaching the steady-state took approximately 0.2 s longer than with the half load (50% torque load). This can be seen in Figure 21a–c.

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**CRITERIA—50% Torque Load; thus, 20 N.m**

**Figure 19.** (**a**) Line currents at 50% loading. (**b**) Electromagnetic torque at 50% loading. (**c**) Electromagnetic torque vs. speed at 50% loading.

**Figure 20.** The speed at 50% loading.

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**CRITERIA—100% Torque Load; thus, 40 N.m**

**Figure 21.** (**a**) Current at 100% loading. (**b**) Electromagnetic torque at 100% loading. (**c**) Electromagnetic torque vs speed at 100% loading. As seen in Figure 22b, the optimal point is at a lower speed than with no-load or half-load.

**Figure 22.** The speed at 100% loading.

*8.3. Dynamic Behaviour of the Machine When (i) the Load Was Suddenly Changed from 50% to 100% and (ii) the Supply Voltage (for the Motors) or the Torque Input (for the Generators) Was Suddenly Halved While the Load Was Maintained at 100%*

As seen in Figure 23a, we have a normal transient state; however, an increase in currents may be seen as the load changes from a half load to a full load (50% to 100%).

As seen in Figure 23b, we have a normal transient state; however, with an increase in the electromagnetic torque, the load changes from a half load to a full load (50% to 100%). It can be seen in Figure 23c that the optimal point of the full load (100%) is at a lower speed; however, there is a higher torque than with the half load.

In Figure 24, we see the decrease in the speed of the machine after 1 s when the load changes from 50% to 100%.

As seen in Figure 25a, the voltage supply is halved at 1.5 s. We can see in Figure 25b that the current at 1.5 s approximately doubles. At 1.5 s, the protection of the induction machine will operate with a disconnect from the supply voltage.

In Figure 26a, at 1.5 s, the machine cannot produce the electromagnetic torque required for the load torque; thus, the speed of the machine decreases. In Figure 26b, we see that no stable point has been reached.
