INDUCTIVE TRANSIENTS

Introduction

Inductor Voltage

Immediately after the switch is closed, the current is still zero, (since it cannot change instantaneously).

Example

E=20 V, Determine i, and VL at the instant switch is closed.

Current Buildup Transients

Applying KVL:

Circuit Voltages

Example

E=50 V, R= 10 ohm, L= 2H

Example

VL for above example:

Time Constant

Interrupting current in an inductive circuit

Interrupting via Resistor

Inductor Equivalent at Switching

De-energizing Transients

KVL:

VL+ VR1+VR2=0

Example

Assume steady state for circuit. E=120 V, R1=30 ohm, R2=600 ohm, L=126 m H

Voltages

Example

Solution

Solution

Solution

Solution

Reading Assignment

Section 14.5, Robbins and Miller’s Book