# How do you find the speed of an alternator?

## How do you find the speed of an alternator?

Speed(RPM) = Frequency(Hz) X 120 / Poles = 100 X 120 / 12 = 1000 RPM.

## At what speed does an alternator rotate?

An alternator has a normal range of operation. Most alternators need to spin at about 2,400 rpm at idle, have their maximum output above 6,000 rpm, and should never exceed 18,000 rpm.

What is alternator in thermal power plant?

An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines.

### What controls the speed of an alternator?

The automatic drive controls the alternator’s rotational speed which allows the alternator to maintain a constant 400-Hz AC output.

### What is the relation between the speed and frequency of an alternator?

The frequency of an alternator is directly proportional to the rotational speed of the alternator.

What are the two types of turbo alternator?

On account of the high rotating speeds, two types of turbo- alternator rotor designs, radial-slot type and parallel-slot type are used.

#### Are alternators constant speed?

Since the various electrical devices operating on ac supplied by alternators are designed to operate at a certain voltage and at a specified frequency, the speed of the alternators must be constant; however, the speed of an airplane engine varies. This stepping up of speed is known as overdrive.

#### What is relationship between frequency and speed of induction motor?

Relationship between Speed and Frequency Let the speed of the rotating magnetic field is N revolution per minute(RPM). In a one complete cycle one pole pairs passes over the coil. Therefore, the frequency of one pole pair passing is N/60.

What kind of speed does a turbo alternator have?

Turbo alternators are cylindrical pole machines having synchronous speeds 3000 rpm (tow pole machines) or 1500 rpm (for four pole machines). Large centrifugal force produced at these speeds, restrict the diameter of the turbo alternators and are characterized by small diameters compared to their length.

## How are alternators used in thermal power plants?

In thermal power plants, in hydel power plants, even in nuclear power plants, alternators only converts mechanical energy to electrical energy for supplying to the power system. Alternators or synchronous generators can be classified in many ways depending upon their applications and designs.

## What is the speed of a salient pole alternator?

A salient pole is a magnetic pole that is projected out of the rotor surface. • The salient pole alternators are slow-speed machines, speed varying from 150 to 600 rpm. These alternators are driven by hydraulic turbines.

How does temperature affect the efficiency of an alternator?

The efficiency with Speed of Alternator: Efficiency of an alternator is reduced when the alternator runs with low speed. Current Drop with Increasing Alternator Temperature: When the temperature of an alternator increased the output current will be reduced or decreased.