Reversible Drives using Phase Controlled Converters: When speed control in both forward and reverse directions is required a Reversible Drives is used. In several applications the speed reversal may be required very frequently in which…
Reversible Drives using Choppers: Using two quadrant choppers a reversible drive can be achieved, because this combination allows reversal of both current and voltage of the motor termiÂnals. We can get a regenerative reversible drive.…
Reversible Drive using Field Reversal: A Reversible Drive using Field Reversal can be realised as shown in Figs. 4.83 and 4.84. In Fig. 4.83, the armature is fed from a two quadrant converter with change…
Reversible Drive using Dual Converter: It is possible to reverse both voltage and current of the load using a dual converter. The current reversal is very fast in this case as the system is static…
Reversible Drive using Armature Current Reversal: A schematic of a reversible drive using contactors to reverse the Armature Current Reversal for reversing the rotation is shown kin Fig. 4.81. The contactors F1Â and F2 are provided…
Reverse Bias PN Junction: When an external bias voltage is applied to a pn-junction, positive to the n-side and negative to the pride, electrons from the n-side are attracted to the positive terminal, and holes…
Restriking Voltage Transient: Electrically a power system is an oscillatory network so that it is logical to expect that the interruption of fault current will give rise to a transient, whose frequency depends on the…
Restricted Earth Fault Protection: This type of Restricted Earth Fault Protection is provided to detect earth-faults within the protected zone of the transformer. A CT is fitted in each connection to the protected winding, and…
Resonant Transformers: The equivalent circuit of a high voltage testing Resonant Transformers consists of the leakage reactance of the windings, the winding resistances, the magnetizing reactance, and the shunt capacitance across the output terminal due…
Resonant Grounding or Arc Suppression Coil Grounding: We have seen that capacitive currents are responsible for producing arcing grounds. These capaciÂtive currents flow because capacitance exists between each line and earth. If inductance L of approÂpriate…
