## Inductors in AC and DC Circuits

The main action of an inductor is to resist a change in current.  However, since the current in a DC circuit is constant, there is no induced voltage developed instantaneously across the inductor.  The inductor does resist the initial inrush of current based on the time constant of the circuit. …

## Capacitors in AC and DC Circuits

Capacitors in DC Circuits             When a capacitor is placed in a DC circuit that is closed (current is flowing) it begins to charge. Charging is when the voltage across the plates builds up quickly to equal the voltage source. Once a capacitor reaches its fully charged state, the current …

## Synchronous Motor Generator: Efficiency & Losses

The losses in a synchronous machine affect its cost, rating, and performance. The efficiency of a synchronous machine is frequently determined by measuring the losses, using techniques that are precisely defined by ANSI, IEEE, and NEMA measurement standards. The efficiency is defined in the same way as it is for …

## Synchronous Motor: Equivalent Circuit & Phasor Diagram

The equivalent circuit for one phase of a synchronous motor is shown in Figure 1. It is similar to the synchronous generator equivalent circuit, but with two differences. First, it has been flipped to show the power system as the input to the motor, and, second, the current is referenced …

## Synchronous Motor Working Principle

The synchronous motor is identical in construction to the synchronous generator, although virtually all synchronous motors are of the salient-pole type. Like all electric motors, the synchronous motor converts electrical power into mechanical power. The primary difference in operation, however, is that the synchronous motor only delivers torque and power …

## How to Synchronize Generator with Grid (Power System) | Parallel Operation of Synchronous Generators

When bringing a synchronous generator online, we are faced with the necessity of paralleling it with the rest of the power system. Figure 1 illustrates the problem. Conditions for Synchronizing the Generator with the Grid (Power System) Once the generator is operating, we would like to close the switch to …

## Synchronous Generator: Performance and Analysis

Most of the electricity we use on a daily basis is created by synchronous generators. Synchronous generators produce constant-frequency power and can operate at both leading and lagging power factors. Delivered power for the round-rotor machine From figure 1, we can write a voltage equation: \$\begin{matrix}   {{E}_{a}}={{V}_{t}}+jI{{X}_{s}} & {} & …

## Synchronous Machine Equivalent Circuit

In the Synchronous Machine section, we have seen that there are two rotating magnetic fields in the airgap of the synchronous machine whether it is operating as a motor or as a generator. Any time a magnetic field passes by a conductor, it will induce a voltage in the conductor. Thus, …

## Synchronous Generator Working Principle

In this section, we will describe the operation of the synchronous generator. Figure 1 shows a cross-section of a round-rotor synchronous generator, and Figure 2 shows a cross-section of a salient-pole synchronous generator. Both are two-pole synchronous generators. The primary difference between the two types is evident from looking at …

## SYNCHRONOUS MOTOR CONSTRUCTION

The synchronous motor, like all other rotating motors, has a stator and a rotor. Figure 1 shows a cutaway view of a synchronous motor. The rotor contains electromagnets, which create the field of the motor. In some cases, permanent magnets are used on the rotor of a synchronous machine to …

## Voltage Source Inverters (VSI) Operation | VSI Working Principle

The voltage source inverter is a somewhat older design and less expensive to implement. Various implementations of the VSI are also known as six-step, twelve-step, or even eighteen-step inverters. Voltage Source Inverters Operation  In the VSI, the switches are turned on and off at regular intervals to deliver rectangular pulses …

## Variable-Frequency Drive Working Principle | Variable-Speed Induction Motor Drive

The induction motor is basically a constant-speed motor, as it operates within 3% of the synchronous speed, which is determined by the frequency and number of poles in the machine: $\begin{matrix} {{n}_{s}}=\frac{120\times f}{P} & {} & \left( 1 \right) \\\end{matrix}$ Although torque at a given slip is proportional to the …

## Pulse Width Modulated Inverter | PWM Inverter

The Pulse Width Modulated (PWM) inverter offers the ability to change both the magnitude of the voltage and the frequency using a fixed DC voltage as the input. This means a diode rectifier can be used as the front end of the drive, which appears as a constant power factor load …