Out of sight, but not without influence

They are well hidden, but nevertheless they play a key role in industries helping to make the world, and our way of living, more sustainable. A water pump controlled by a frequency converter, which reduces motor speed with lower water consumption, increases pump life and reduces electricity consumption. The frequency converter also maintains a constant pressure in the system and protects the pump against dry running.

A good design matters

A good design truly matters, when it comes to inductive components for AC drives. It matters to the size, performance and total cost. That is why you want optimum inductive solutions for your AC drives – in terms of efficiency, cost, compact design and maximum output for your AC drives.

We are experts in combining technical knowledge and insight from our extensive experience in the field to create new, optimised solutions for AC drives in pumps. Millions of AC drives applications round the world are equipped with Kohsel components.


Ultra-low harmonic distortion using active front-end with an LCL filter

Ultra-low harmonic drives, with an LCL filter, lower the pollution to a minimum. Finding the right balance of temperature, size, and price on the LCL filter chokes can be difficult. We are ready to use our extensive knowledge and industry know-how, as well as our experienced engineers, to design the cost-efficient LCL filter chokes for your AC drive.

We are all about optimisation

At Kohsel, we combine technology, supply chain management and manufacturing knowhow in solutions that reduce cost at every step of your value chain and optimise performance through innovative and reliable technology. It’s this ability to optimise and reduce the total cost of ownership for our customers that sets us apart.

Some of our products

DC link choke

A DC link choke is used to mitigate the impact of harmonics from the converter and increase the lifespan of the line side inverter bridge.

Common mode choke

The common mode choke blocks high frequency noise while allowing the low-frequency signal to pass. Common mode chokes with nanocrystalline cores have a high attenuation over a wide frequency range, offering an extreme broadband attenuation.

PFC choke

The power factor correction (PFC) choke increases the efficiency of the circuit, by bringing the voltage and current waveforms into in phase. With PFC chokes, the energy efficiency is increased, and the circuit components can be reduced in size and cost.

LCL filter choke

The switching action of the battery charger generates total harmonic distortion (THDi) in power output. The LCL filter is used to reduce the harmonic distortion.

From crimping terminals to cost-efficient ultrasonic welding

Did you know that the terminals you choose affect the processing time in the production of your AC drives?

If not, you might be missing out on potential savings.

A client of ours proves this. They were using a particular DC link choke in the frequency converter inside the pumps they produce. The input and output of this DC link choke were flying leads with multi-strand copper wire crimped on two UL approved terminals.

We reassessed this solution because we knew better and more cost-efficient solutions were available. We then presented the idea of going from a traditional crimping solution to a new and faster solution utilising ultrasonic welding.


  • The processing time of the new solution was significantly faster than crimping
  • We even lowered the failure rate of the new DC link choke
  • We saved the cost of the two UL approved crimping terminals
  • The client saved 7% on an annual consumption of 30,000 component

External reactors, chokes and filters

Line reactors

Reduce low frequency interference (harmonics) and relieve the strain on the grid network by compensating for the distortion reactive power induced.

Harmonic filters

Reduce current harmonics (THDi) to comply with the limit values required under the standards. This protects the connected grid network from circuit feedback and increases the system immunity from interference. Our LCL filters are specially designed to reduce harmonics of current absorbed by the rectifiers in the input converter.

Motor chokes

Reduce the voltage rise and the voltage spikes between the conductors which become more pronounced as cable length increases.

dV/dt filters

Protect motors against high voltage increases and voltage peaks at the motor terminal.

Sinus filters

Effectively protect the motor insulation and reduce supplementary losses and noise emissions from the motor. All-pole sine filters also enable the use of unshielded motor lines.

Our certificates

Kohsel is committed to providing customers with the highest-quality products, but also aspires to the highest standards of social responsibility and ethical conduct. Our core values support a strong commitment to economic, environmental and socially sustainable development.

Our journey started back in 1969. More specifically at Skovvænget 7 in a town near Aarhus down in Poul-Erik Kohsel and his wife Hanne’s basement. This was where it all began. Soon after that the basement was replaced with a factory nearby. Years after new markets were conquered, new factories in Europe and Asia were built and many people have been employed since then.