# Why Synchronous Motor Is Called A Condenser?

## What is meant by synchronous condenser?

In electrical engineering, a synchronous condenser (sometimes called a synchronous capacitor or synchronous compensator) is a DC-excited synchronous motor, whose shaft is not connected to anything but spins freely. One advantage is the amount of reactive power from a synchronous condenser can be continuously adjusted.

## How the synchronous motor is used as a synchronous condenser?

Like capacitor bank, we can use an overexcited synchronous motor to improve the poor power factor of a power system. When a synchronous motor runs with over-excitation, it draws leading current from the source. We use this property of a synchronous motor for the purpose.

## Why synchronous motors are known as synchronous capacitors?

When the motor is operated at no load with over-excitation, it takes a current that leads the voltage by nearly 90 degrees. Thus, it behaves like a capacitor and under such operating conditions, the synchronous motor is called a synchronous capacitor.

## What is AC synchronous motor?

A synchronous electric motor is an AC motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles. The synchronous motor and induction motor are the most widely used types of AC motor.

## What is the function of synchronous condenser?

The synchronous condenser aids voltage regulation by drawing leading current when the line voltage sags, which increases generator excitation thereby restoring line voltage. A capacitor bank does not have this ability.

## What is synchronous speed?

Synchronous speed is a significant parameter for the rotating magnetic field-type AC motor. It is determined by the frequency and the number of magnetic poles. Synchronous speed No = [rps, revolutions per second] f = Frequency [Hz] p = Number of magnetic poles.

## How do you start a synchronous motor?

The motor is first started as a slip ring induction motor. The resistance is gradually cut-off as the motor gains speed. When it achieves near synchronous speed, DC excitation is given to the rotor, and it is pulled into synchronism. Then it starts rotating as a synchronous motor.

## What are the applications of synchronous motor?

Synchronous motors are normally used in applications in which a constant and precise speed is required. Typical applications of these low power motors are positioning machines. They are also used in robot actuators. Synchronous motors are also used in ball mills, watches, record players, and turntables.

## How much does a synchronous condenser cost?

The cost of a synchronous condenser depends on a range of factors such as the size of the unit. As an example, a 50-70MVA synchronous condenser may be sufficient to offset adverse system strength impacts from a 200MW project. The cost of such a unit is typically \$15-20 million.

Synchronous motors requires dc excitation which must be supplied from external sources. Synchronous motors are inherently not self starting motors and needs some arrangement for its starting and synchronizing. The cost per kW output is generally higher than that of induction motors.

## How synchronous motor works as a power factor correction?

The power factor of a synchronous motor is changed with a change in the excitation. When the excitation of the motor is increased, the power factor changes from lagging to unity and then to a leading power factor.

## How power factor is improved?

The simplest way to improve power factor is to add PF correction capacitors to the electrical system. PF correction capacitors act as reactive current generators. They help offset the non-working power used by inductive loads, thereby improving the power factor.

## What is the principle of synchronous motor?

Working of synchronous motors depends on the interaction of the magnetic field of the stator with the magnetic field of the rotor. The stator contains 3 phase windings and is supplied with 3 phase power. Thus, stator winding produces a 3 phased rotating Magnetic- Field.

## Are brushless motors AC or DC?

Brushless DC motors are DC motors in the sense they are fed from a DC source. They use, however, an inverter (a type of power electronic converter) as an “electronic commutator” to provide an alternating current in accordance with the rotor position so that it can generate the torque.

## What are the types of motors?

Each motor has a specific application. Basic motors have been classified into three distinct types: AC motor, DC motor, and specialized motors.