Frequency Converter

Frequency converters are electric devices that convert a current with a certain frequency to a current with a different frequency.

A frequency converter is a power conversion device that allows you to convert the current with a particular frequency to a current with a different frequency without changing the voltage. They regularize the speed of the motors of fans and pumps by converting the fixed-frequency sine wave power to variable frequency while keeping the voltage of the current constant.

In old times, People used stroboscopes to measure the frequency of rotating objects. However, in today's modern world, frequency converters are used for this purpose. The frequencies above the level of the frequency converter are measured by the Hydrodyne method. For example, if a fan is provided with 220VAC, 100 HZ, the fan will run at this specific speed. If you want to increase the fan's speed or reduce the fan's speed, a frequency converter will change the frequency of the fan according to which speed of the fan will change. Furthermore we have also provided charge converter for more calculation you can check the tool.

What is the frequency? How can you determine it? What are the different types of it? How can frequency converters be helpful in daily life? If you are looking for the answers to all of these queries, you are in the right place. I will answer your questions in this article and further explain different types of frequencies and their SI-derived units; please read it till the end.

Frequency Converters

What is The Frequency?

According to Physics, frequency is the total number of waves passing through a point in a unit of time. It is also defined as the number of cycles or vibrations of a body in a unit of time in periodic motion. It's easy to calculate the frequency of a wave by measuring the time it takes to complete a cycle. If a wave takes 1/50 hours to complete one cycle, then the wave's frequency would be 50 per hour. The formula calculates the frequency of a wave

f =1/T, where T refers to the period the wave takes to complete a cycle.

The letter f is commonly used to represent the frequency of the wave. However, some textbooks and articles use nu(v) or Omega (w) to describe the wave's frequency. While discussing the frequencies of UV and gamma rays, authors use the greek letter nu(v); on the other hand, Omega (w) is used to demonstrate the angular frequency of an object.

Unit of The Frequency

The SI unit of the frequency is Hertz(Hz). One Hertz is equivalent to one cycle per second. The frequency unit Hertz is named after the well-known German Physicist Heinrich Rudolf Hertz, who has done remarkable work to prove the existence of electromagnetic waves. Hertz is commonly expressed in kilohertz, megahertz, gigahertz, and tetrahertz.


Kilo Hertz (kHz)=10^3 Hertz

Mega Hertz(MHz)=10^6 Hertz

Giga Hertz(GHz)=10^9 Hertz

Tetra Hertz ( THz)=10^12 Hertz

Types of Frequencies

Angular Frequency

Angular Frequency is defined as the rate of change of angular displacement or rate of change of sine wave. Angular frequency is also termed a radial frequency or circular frequency. It describes how fast an object rotates or a sine wave oscillates. It is also referred to as the rate of change of sinusoidal wave. Angular velocity is commonly expressed in terms of Omega.

Angular velocity is described as an object which goes through a periodic motion, such as a ball tied at the end of a rope and swung in a circular path, the rate at which the ball sweeps through a complete 360. Its unit is rad/sec.

Its formula is as follows



⍵=angular velocity

T= period''


Angular frequency has no dimension, meaning it is a scalar quantity with only magnitude. It is easy to calculate the angular frequency of an object by using its formula if you have period time T, which the object takes to complete one cycle or revolution. For example, if a thing is oscillating and has 30 seconds. Then, its angular frequency is 12^°/sec.

Spatial Frequency

In Mathematics and Physics, Spatial frequency is described as the characteristics of any periodic structure across positions in space. In simple words, spatial frequencies or wave numbers mean frequencies in space, which are analyzed by Fourier transformations. It is similar to temporal frequency and tells us how often sinusoidal components of the structure repeat per unit of the distance. The SI unit of the Spatial frequency is cycles per meter.

In wave propagation theory, Spatial frequency is known as wave number, which is the reciprocal of the wavelength. The amazing fact about spatial frequency is that it demonstrates the periodic distribution of light and dark in an image. High Spatial frequencies show the features such as sharp edges and fine details; on the other hand, low spatial frequencies correspond to features like global shape. As I stated earlier, it is similar to temporal frequency; the only difference is that a spatial axis takes the place of a time axis.



Here, the spatial frequency is denoted by k, and its unit is rad/meter.

The spatial frequency of the periodic wave depends on whether they are present in non-dispersive or dispersive media. The spatial frequency of the sine waves in dispersive media is directly proportional to the phase velocity and is inversely proportional to the wavelength.

f ⍺ v………………(i)

f ⍺ 1/ƛ…………….(ii)

Combing (i) and (ii), we get,


The frequency of the electromagnetic waves is calculated by f=c/ƛ, as in a vacuum, v=c for the electromagnetic waves, where c is the speed of the light.

Types of Frequency Converters

Frequency converters are of two types, rotary frequency converters, and solid-state frequency converters. Rotary frequency converters, also known as Motor-Generators or MG Sets, use electrical energy to operate the motor. Solid-state frequency converters convert the alternating current (AC) to the direct current (DC).

What is a Cumulative Frequency?

Cumulative frequency is the total number of all frequencies that lie above or below the reference line. For example, let the raw data be 3,6,9,12,15,16,18,19,20. The cumulative frequency for 15=5( since values ≤ 15 are 3,6,9,12,15).

What is a Frequency Distribution?

The graphical and tabular representation of the frequency observed by the observer for a specific interval of time is known as the frequency distribution. Frequency distribution has many types, ungrouped frequency, grouped frequency, and relative frequency distribution. A grouped frequency distribution shows the scores by grouping the observations into class limits and then enlisting the class limits in the frequency distribution tables. Here, class limits refer to intervals of comments.

On the other hand, ungrouped frequency distribution displays the frequency of each data value instead of grouping them. The relative frequency distribution is one of the commonly used distributions as it has the edge over other distributions, as its graphs will directly compare the samples of different sizes.

What is a Frequency Polygon?

The frequency polygon is the visual representation of the distribution, allowing you to understand the shape of the distribution. In other words, A frequency polygon is a graph that plots the midpoints of the class interval against the frequencies and then joins up the points with straight lines. It is just like a histogram, as it shows the same information but in a different way.


What can be controlled by a frequency converter?

The primary purpose of using frequency converters is to regulate the speed of motors that drive pumps and fans. Moreover, a frequency converter converts the current with a specific frequency to the current with a different frequency while keeping the same voltage.

How do you choose a frequency converter?

The converter's rated current should be higher than the load-starting draft. It is recommended that the current of the frequency converter must be six times higher than the motor's current.

What is the basic principle of frequency conversion?

In simple words, frequency converters are power conversion devices. They convert the fixed frequency current to a current with variable frequency.

What is the advantage of the frequency converter?

The frequency converter gives you control over the motors, which is a significant advantage in the industry. It allows the engine to start at a low speed. Unlike the traditional stop-and-go motor, you can also make remote adjustments to the motor with the programmable controller.

Bottom Lines

The frequency of a wave is the total number of waves that pass through a specific point in a unit of time. The frequency's SI-derived unit is Hertz, equivalent to one cycle per second. The base unit of the frequency is s^-1. The Hertz is expressed in kilohertz, gigahertz, megahertz, and terahertz.  The frequency converter is an electric device that accepts power intake, usually 50 to 60 Hertz, and converts it to 400 Hertz output power. It is also known as a power frequency changer. There are two types of frequency converters, rotary frequency converters, and solid frequency converters.

The frequency distribution is the representation of frequencies recorded over a specific period. There are three types of frequency distribution: grouped, ungroup, and relative. The relative frequency distribution has the edge over other distributions as it can be used to compare different data samples directly. The current of the frequency converter must be six times higher than the motor capacity. Frequency polygons are the line graphs of class frequency plotted against class midpoints. Frequency converters are vital in industries.