Reactance External

When the external impedance is a resistance or a capacitive reactance... 

Vg = voltage across the external resistance R R = external resistance X = ground capacitive reactance Vf = line voltage... 

Equation (7.2) can be used to calculate the situation at the time given for the breaking duty. Usually the sub-transient time decay term has fallen to zero, and the solution is in the transient period. When an external impedance is present its resistance can be included in the Ta time constant and its reactance added to the appropriate machine reactances. References 5 and 6 explain how the derived reactances and time constants are calculated and affected by the addition of the external impedance. 

In a situation where the disturbance is remote from the machine the short circuit time constants and the derived reactances X, X, X, Xq, (Xp, X" and X2 are all functions of the external reactance Xe since it should be added to Xa. Likewise Re should be added to Ra- Ra does not appear in the time constants except for Ta. 

Measurement of Membrane Capacitance. A sufficiently high frequency of light modulation is chosen so that Rm is large compared to the AC impedance (i.e. capacitive reactance) of the membrane. Therefore, in depletion, I can still be described by the relative magnitudes of the internal and external capacitances (Equation 4). As long as Cm Ci (which can be controlled by the size of the illuminated region on the insulated semiconductor), Equation 4 can be transformed into a linear form (Equation 4a). 

VFD s with high frequency switching characteristics should include input filtering equipment when installed on systems supplied by diesel generators and weak utility supply systems. This input filtering can consist of line reactors (reactance can also be built into drive step-down input transformers if apphcable), LCL-style input filters, and external third-party wideband harmonic filtering equipment. 

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