Starting and speed control at constant frequency and voltage
Asynchronous machines - Continuous operation

Figure 14a shows the usual admittance diagram for a motor of the industrial type: the center C and very close to the reactive power axis, the points P ₁ and P_× are very close both to each other and to this axis. The point P _n, corresponding to the nominal slip g_n , is located in the left-hand part of the circle so that O P _n (nominal current) is much lower than O P ₁ (starting current). If voltage U is applied to a motor at standstill, the current absorbed in the first moments of starting is much higher than the normal...