Built-in Frequency Inverters

Table of content:

  1. What is an embedded VFD
  2. Features of this type of frequency converter

Industrial and domestic asynchronous motor systems are widespread. Their development and implementation started a long time ago, so most of them no longer meet modern requirements for economy or controllability. At the same time, a complete replacement of this type of equipment is not economically justified and is not always possible, especially since such a fleet can be quite easily upgraded using integrated frequency inverters to expand the equipment control and process automation capabilities.

The same can be said of new equipment which is being developed based on the popular and sought-after asynchronous motors with single- and three-phase power supply, widely used for production tasks as well as in households. Such equipment is already being developed with the use of motor shaft speed control technology using frequency inverters, which have already become affordable and have a rich functionality and simple control that is sufficient for most practical applications.

However, it should also be remembered that the design of this type of equipment has been in use for quite some time and has been optimised, so it is not always possible to fit it into a free space in a product casing or switch cabinet, and reworking the technical documentation and changing the production technology may also not always be economically justified and may be time-consuming.

It is for this purpose that a number of manufacturers in the electric motor control market offer specialised ranges of frequency inverters with which the above tasks can be performed quickly, inexpensively and with minimal need for modification of the complete construction.

What is an embedded VFD

A frequency converter of this type does not differ in principle from a classic frequency converter. The main differences between a frequency converter that is integrated into existing equipment are:

  • a compact enclosure that allows the unit to be placed in the free space of a drive switch box, machine or integrated switch cabinet with limited free space;
  • simple control technology via a built-in or remote control panel. The remote panel can be mounted in a convenient position close to other equipment controls;
  • the minimum necessary adjustments before commissioning the equipment.

That is, as a rule, this range of equipment is available in compact enclosures, has minimalist functionality, which is sufficient for typical applications, and requires minimal set-up, which is sufficient for commissioning purposes.

With regard to the type of enclosure design in which frequency inverters are available, there are several variants, including:

  • the inverter in a classic compact housing. It has a small footprint, so you can easily find space for it in existing equipment;
  • frequency control unit with a minimalist casing containing only the electronic frequency control circuitry, the controls are connected via terminals provided on the casing;
  • inverters with the option of mounting directly on the motor or in a motor switch box. The first option is only suitable for certain sizes and brands of electric motors, so they are not as common and are used directly in the production or modification of large series of electric motors.

Features of this type of frequency converter

Built-in frequency inverters have a number of features and limitations, mainly related to their area of application and the compact size of the enclosure. For this reason, it is relatively low-power equipment, allowing the control of electric motors up to a few kilowatts.

Examples of such frequency inverters that can be integrated into complete systems without significant modification are:

If you need to select and buy frequency inverters to integrate into existing equipment for retrofit or manufacture, you can always contact us for advice and help with your selection. 

We have a wide range of equipment from different manufacturers, so we are always able to select the best option in terms of motor characteristics, system requirements, price, as well as the size and form factor of the free space that can be allocated for the installation of a device.


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Bonfiglioli Inverters (VFD)
Fuji Electric Inverters (VFD)
Hitachi Inverters (VFD)
LS Inverters (VFD)
Mitsubishi Inverters (VFD)