Variable frequency drives for maximum performance

With variable frequency drives from KOSTAL, you always control the speed of your three-phase motors to suit the requirements of your application – the smart way. Save costs, gain more flexibility and get the most out of your drives with certainty.

Ein KOSTAL INVEOR MP Frequenzumrichter der Performance-Serie auf einem Elektromotor

Performance variable frequency drives

Wall-mounted or motor-mounted variable frequency drives for your most stringent requirements.

Ein KOSTAL INVEOR M Frequenzumrichter der Core-Serie auf einem Elektromotor

Core variable frequency drives

The mid-range wall- or motor-mounted device. Saves energy while providing high performance.

Schematische Darstellung des Pulsinjektionsverfahrens eines KOSTAL INVEOR Frequenzumrichters

Pulse injection method

The pulse injection process ensures maximum efficiency in sensorless control technology.

Specific devices

Scope for individual device adaptation


Customised accessories for optimum integration

Zwei Ingenieure entwerfen einen Frequenzumrichter

Variable frequency drives from KOSTAL

Today's variable frequency drives have to deliver top performance. Because industrial processes are becoming more complex by the day, which means that the demands on technology are also increasing.

As a manufacturer with the highest standards, here at KOSTAL we therefore produce variable frequency drives that integrate into your processes with smart technology. And we even optimise them if required.

From wall-mounted variable frequency drives with extremely simple commissioning to motor-mounted drive controllers that have no need for without encoders and sensors – at KOSTAL, you will find variable frequency drives for all motors and all requirements. Compliance with the Ecodesign Directive included. 

Motor-mounted variable frequency drives from KOSTAL: All the benefits at once

Discover our motor-mounted variable frequency drives of the Core and Performance class. And enjoy numerous benefits:

  • Space and cost savings as mounting on the motor fully eliminates the need for a control cabinet.
  • Less cabling and better EMC values thanks to decentralised installation.
  • Shorter distances and time savings through commissioning close to the motor.
  • Greatest possible flexibility – control all motor types with maximum efficiency using one and the same device. 

In addition, you benefit from the advantages of encoderless regulation thanks to the patented pulse injection process. By dispensing with the sensor, the most sensitive component is eliminated, giving you a robust drive controller that extends the application range of your electric motors many times over, while at the same time determining the rotor position perfectly.

Ein Schaubild eines KOSTAL INVEOR Frequenzumrichters mit Adapterplatte und Elektromotor

Our motor-mounted variable frequency drives

Motormontierter Frequenzumrichter KOSTAL INVEOR M auf Drehstrommotor


Our particularly robust motor-mounted frequency inverter with up to 22 kW. Supports motors up to IE4 and offers extra features for almost all your requirements.

Motormontierter Frequenzumrichter KOSTAL INVEOR MP auf Drehstrommotor


Our motor-mounted performance flagship with up to 200% overload, maximum speed control range and much more. Available in four sizes with up to 30 kW. 

Ein KOSTAL INVEOR MP Modular Frequenzumrichter der Performance-Serie auf einem Elektromotor Dateiname: kostal-inveor-mp-modular-frequenzumrichter


Our modular variable frequency drives with smart power stack or the option of integrating your own application boards and electronics. Available in four sizes with up to 30 kW.

More information about variable frequency drives

  • A variable frequency drive, also known as a drive controller or frequency inverter, is an electronic component that allows you to adjust the input voltage of an electric motor to the actual demand. This is done by adjusting the frequency (occurrence) and amplitude (voltage level) parameters. 

    Without a variable frequency drive, your motor would only have a fixed speed available. This is because the electrical energy of the input voltage is a constant force and therefore only enables a constant torque. However, this severely limits the motor's possible uses. 

    Moreover, since the input voltage is often the supply voltage, it is very high, which may result in faster wear of the motor and the machines connected to it. As a result, maintenance and repair costs also increase.  With an efficient frequency inverter, you can avoid these costs. While at the same time reducing your energy consumption and ensuring flexible speeds and processes.

    Variable frequency drives and motors: Form must follow function

    Adjusting the input voltage with a frequency inverter has many advantages. Among other things, you can adapt the speed control of the electric motor to your processes. And this is true across many sectors.

    Be it the speed of a conveyor belt, an agitator or pump system or a large roller shutter – thanks to the controlled and monitored motor control of a variable frequency drive, your technical infrastructure adapts to your processes and not the other way around. And depending on the quality of the variable frequency drive, you can even do this with programmable and fully automatic processes. For maximum efficiency. In every respect.

    Advantages of a drive controller at a glance:

    • Time-optimised processes as more efficient speed control and programming
    • Reduced energy costs as reduced power consumption and more efficient energies can be used
    • Lower noise level as motors do not run constantly at full load
    • Lower maintenance costs as there is less wear and tear
    • Optimised torque as almost perfect settings with ± 0.5 % tolerance 
    • More room for manoeuvre as motors can now autonomously perform several processes

    Furthermore, modern frequency inverters offer a wide range of diagnostic functions, such as monitoring the motor temperature. This also helps to avoid breakdowns. And ensures even more efficient processes.

  • Variable frequency drives come in many variants and with a wide range of performance parameters. For a rough overview, we recommend dividing them into the following categories:

    • Control cabinet units
    • Wall-mounted variable frequency drives
    • Motor-mounted variable frequency drives

    All three categories have different characteristics. So that you know which type is best for you and your company, we have provided a few explanations below.

    Frequency inverters mounted in control cabinets

    Frequency inverters in control cabinets are among the most commonly found variable frequency drives. With these, the drive controller is located in a control cabinet at some distance from the motor environment and is connected to the motor via a cable. The variable frequency drive controls torque and other parameters via this connection.

    A major advantage of this technology is that all frequency inverters are centrally accessible in one place and away from the motor environment that may be harmful to the variable frequency drive. However, suspension in a control cabinet may lead to increased temperatures, meaning that electrical climate control may be necessary. This in turn increases energy consumption and costs.

    Sometimes this involves long cable runs from the frequency inverter to the three-phase motor, which may also increase the risk of electrical interference and EMC values. 

    Wall-mounted frequency inverters 

    Wall-mounted frequency inverters are located in close proximity to the motor. They therefore have shorter cable connections than the frequency inverters mounted in control cabinets, but are still outside a potentially damaging production environment. Since heat does not build up they also do not require external climate control, unlike the control cabinet scenario, so they help to save electricity. 

    Another advantage of wall-mounted frequency inverters is that they are less susceptible to interference resulting from the shorter cable connection. At the same time, this translates into less installation work and a clear, uncluttered look. 

    Examples of wall-mounted variable frequency drives are our KOSTAL VERTIMO products. You are welcome to find out more about this type of drive controller and click on the link to access the relevant product page.

    • KOSTAL VERTIMO: Our wall-mounted drive controller if you want easy commissioning. Learn more now.
    • KOSTAL VERTIMO E: Our wall-mounted drive controller with a high motor rating. The perfect frequency inverter for use with fans and pumps. Learn more now.

    Motor-mounted variable frequency drives

    Motor-mounted variable frequency drives are mounted directly on the respective three-phase motor. There is therefore no need whatsoever for annoying cables and heat-generating control cabinets. This ensures the greatest possible flexibility, which is why this type of variable frequency drive can also be described as an all-rounder in terms of its mode of operation.

    Due to their decentralised connection method, motor-mounted frequency inverters also accommodate a wide range of technologies: From various interfaces for the respective fieldbus systems to Bluetooth for setting up using an app. This makes variable frequency drives of this type, such as our KOSTAL INVEOR family, the ideal choice if you value the greatest possible flexibility and wide-ranging application options. 

    KOSTAL INVEOR motor-mounted variable frequency drives: Vibrations? No problem

    An important criterion for motor-mounted drive controllers has always been robustness. This is because they are mounted in close proximity to fast-rotating motor components. In the past, the resulting continuous vibration used to damage the sensors responsible for determining the rotor position within the motor. 

    However, here at KOSTAL, we were able to solve this problem with the new patented pulse injection process. Because the motor-mounted variable frequency drives of our INVEOR family no longer have any sensors.

    The pulse injection process in our INVEOR drive controllers now handles the task of determining the rotor position, which was previously the job of the encoder. This is a particularly important task, because only if you know where the rotor is located can you control the motor perfectly. 

    Thanks to this process, the rotor can now also be determined in close proximity to the motor and without ongoing maintenance and repairs. This is an important step towards flexibility, which enables you as a user to meet the requirements of the Ecodesign Directive and save money at the same time. 
    Discover our motor-mounted variable frequency drives from the KOSTAL INVEOR family today:

    • KOSTAL INVEOR M: Our robust, mid-range, motor-mounted drive controller. Supports motors up to efficiency class IE4. Learn more now.
    • KOSTAL INVEOR MP: Our motor-mounted variable frequency drive from the Performance class. Supports all motor types up to efficiency class IE5. Learn more now.
    • KOSTAL INVEOR MP Modular: Our Modular Performance drive controller for the extended speed control range. Individual modifications make it possible to fit the products perfectly into your company. Learn more now.
    • KOSTAL INVEOR P: Our cold plate drive controller without its own housing. For seamless integration into your application.

    If you are wondering whether it is also possible to connect a motor-mounted frequency inverter to your motors: The versatile adapter plates from KOSTAL provide the answer – yes and with ease. For any type of three-phase motor.

  • The job of variable frequency drives is to variably adapt the electrical input voltage of the motor to the demand. This is done by changing the frequency and amplitude of the incoming current. However, a variable frequency drive should not be confused with a frequency changer. This performs a similar task, but works with mechanical rotation and its own motors. 

    The structure and function of the frequency inverter are as follows:
    The rectifier in the variable frequency drive transforms the input voltage into a pulsating DC voltage. This is stabilised by a subsequent intermediate circuit. In the subsequent inverter, the stabilised DC voltage is finally converted into AC voltage. This is variable and thus represents the adjustment of frequency and amplitude mentioned at the outset.

    The whole thing is controlled via the control circuit, which is connected to the rectifier, intermediate circuit and inverter. The control circuit is also the component containing the control board where you enter the performance parameters via an interface – so that the frequency inverter works exactly as you want it to.
  • Variable frequency drives can be used wherever three-phase motors require their speed to be controlled. Depending on local requirements, we would then recommend either a wall-mounted or motor-mounted device.

    As a variable frequency drive manufacturer with many years of experience, we can supply you with drive controllers for all requirements. Are you looking for single-phase variable frequency drives with 1.5 kW power or less for smaller motors? Or three-phase variable frequency drives with 400 V and 4 kW or more? 

    Our frequency inverters cover everything from 0.25 to 30 kW in the motor-mounted range. This is sufficient for a wide range of applications in many different sectors.
    The wall-mounted frequency inverters in the VERTIMO E series even deliver up to 90 kW, leaving nothing to be desired in terms of possible applications.

The optimum variable frequency drive for your sector

Discover the sectors in which our products are used. And get an idea of the versatility of smart KOSTAL drive controllers.

Keyfeature-Liste der KOSTAL Antriebsregler

Do you have any questions about our variable frequency drives?

Complete our contact form or give us a call. We will answer your questions and help you to implement the right frequency inverter solution in your company.

KOSTAL support for new and potential customers

KOSTAL Industrie Elektrik GmbH & Co. KG / Business Unit Drives
Lange Eck 11
58099 Hagen, Germany

Telephone: +49 2331 8040 - 468

Eine Kundenberaterin telefoniert mit einem Headset

Your message to us

KOSTAL variable frequency drives


Contact our KOSTAL Drives Technology Support Team.


Get information about encoderless control processes, operating concepts and more.

Line-Icon eines Frequenzumrichters auf einem Elektromotor

Variable frequency drives

Learn all about KOSTAL variable frequency drives and discover our product solutions.