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Device for automatic testing of power capacitors offered for licensing

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Partner keyword: 
Electrical Engineering/ Electrical Equipment
Generators, electric engines and power converters
Other energy related machinery
Energy management
Electrical Technology related to measurements
Network test, monitoring and support equipment
Energy Distribution
Energy management
Power transmission equipment (including generators & motors)
Engineering services
Manufacture of electric motors, generators and transformers
Manufacture of electricity distribution and control apparatus
Transmission of electricity
Electrical installation
Technical testing and analysis


Researchers from the Czech university have developed and successfully implemented a special device that allows to test power capacitors in the mode when the alternating current passes through them, usually with high frequency and units up to tens of amperes, while the needed electric power and demands for the testing equipment are minimized. The researchers are looking for manufacturing partners interested in a licensing agreement.



A team of the Czech researchers have developed and successfully tested a new device, which principle is based on the invention that tested power capacitor is complemented with a low-loss inductor with loss factor comparable to the loss factor of the tested power capacitor (or lower) to form a parallel oscillating circuit.

Nowadays, the capacitors are tested using Ohms method.
The capacitor is feed with power signal source and the Voltage and current values are observed. The drawback of such tests is that all the current and voltage used for the test must be supplied with the signal source and the source is loaded with reactive power.

The newly introduced equipment enables ultra-precise reactive-power compensation of the tested capacitor in the measuring circuit and matching of the measuring circuit to the driving generator by completing the tested capacitor with the inductor so that the resonant circuit is tuned to the measuring frequency.

The inductor’s inductance is set in the way that at the testing frequency it has the same reactance as the tested power capacitor. The described solution ensures the needed precise compensation of the tested capacitor’s reactive power, which can be viewed as complementing the tested capacitor with the inductor in the way that creates an oscillating circuit tuned at the testing frequency, by automatic correction of the measuring frequency according to instantaneous value of
the oscillating frequency of the measuring circuit. The frequency is controlled by a feedback loop with the voltage-controlled oscillator, integrator and phase detector.

The researchers are looking for manufacturing partners (e.g. manufacturers of power capacitors) interested in a licensing agreement. The subject of the licensing will be know-how (power capacitor principle, detailed scheme of working etc.) as well as know-how for manufacturing of the power capacitor device.

Advantages & innovations

Cooperation plus value: 
-Highly accurate compensation of the reactive power of the tested capacitor in the measuring circuit and matching the measuring circuit with the exciter generator - The newly developed and tested power capacitor reach the condition when the exciter generator supplies no reactive power and the delivered real power, covering losses in the measuring circuit elements - The device allows (for stabilization of the tested capacitor) load level during testing.

Stage of development

Cooperation stage dev stage: 
Already on the market

Partner sought

Cooperation area: 
The university would like to cooperate with a partner from industry (e.g. manufacturers of power capacitors), who would like to manufacture the offered technology based on licence agreement.

Type and size

Cooperation task: 
SME 11-50,SME <10,>500 MNE,251-500,SME 51-250,>500


Reference device during tests


Offered device