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Contact Info

Sales at Kodensya

Kodensya Co., Ltd.

Phone: +81 982-20-7007 / Fax: +81 982-20-7014

222-1 Hamamachi, Nobeoka-shi, Miyazaki, Japan 882-0862

Frequently Asked Questions (FAQs)

What does this unit do?
The Inrush Limiter T1 resolves various problems that are caused by the inrush phenomenon that occurs when a transformer that is connected to an electrical power system is energized. The Inrush Limiter suppresses the inrush phenomenon by control the timing at which the circuit breaker is closed.
What is inrush current?
When a transformer is energized, the steel core in the transformer becomes magnetically charged until it reaches saturation. At this time, an impulsive large electrical current flows through the core. This flow can last anywhere from several seconds to several tens of seconds, or even minutes. The current can be several times to several ten times the current that the transformer is rated for.
What is residual flux?
Residual flux refers to the flux that remains in the steel core of the transformer after disconnection.
What kind of problems does the inrush phenomenon cause?
It can cause erroneous operation of electrical protection circuits, motor failure, IT equipment (PCs and servers) shutdowns, loss of data, product line control equipment failure, household appliance failures, and many other electrical failures. A series of these events can bring production lines to a halt, or cause major inconveniences to daily life.
Where is the Inrush Limiter intended to be used?
Electric power companies, public and private power generation stations, substations, power distribution stations, etc. Recently, the Inrush Limiter has also been used by heavy electricity users who use transformers for connecting to power systems, such as businesses that operate distributed power supplies for full buyback programs with renewable energy sources, such as wind power, mega solar, and biomass power generation.
What are the benefits for substations?
The Inrush Limiter benefits distributed power supplies—for interconnecting wind and solar power to electrical power systems—and power receiving substations for factories.
What is the key appeal of this product?
The Inrush Limiter addresses true residual flux, an original concept that we discovered on our own and proved in both theory and by actual use. The Inrush Limiter also uses a control algorithm that matches the phases between the residual fluxes and the power voltage when the transformer is re-energized.
What are the features of this product?
The Inrush Limiter has the following features when compared with existing systems:
  • less installation space and lower cost
  • not limited by voltage grades or transformer capacity
  • can be introduced into existing facilities without modifications to the primary circuitry
Where has the Inrush Limiter been used?
Electric utility companies; heavy electricity users such as factories with electric furnaces, chemical plants, etc.; solar and wind power generation companies, and companies in the railway industry.
What kind of reputation does it have?
Our customers have confirmed the effectiveness of the Inrush Limiter through testing during installation and actual operation. In all cases, the responses have been very good.
Do you have a sales agent?
In Japan we sell direct.In Taiwan, San Lien Technology Corp. and Precision International Corp. handle the Inrush Limiter.
Is the Inrush Limiter available mounted in a cabinet?
The Inrush Limiter can be purchased as a stand-alone unit or mounted in a cabinet. Contact us for details.
What is your lead time?
We ship four months after receipt of order.
Is there any maintenance?
The Inrush Limiter is designed to be free of maintenance. There is no daily maintenance. We do recommend a regular inspection of the unit once every two to three years to ensure stable performance.
Are there any limitations by voltage class or capacity?
No, there are no limitations.
Are there any limitations by specifications of the transformer or circuit breaker?
No, there are no limitations.
What standards does it comply with?
The Inrush Limiter complies with IEC standard B402 classified for electrical power use. Kodensya will consider compliance to other international standards upon request.
What is the lifetime of the Inrush Limiter?
The Inrush Limiter can be used for prolonged periods as with other protective relays and control equipment used for electric power applications.
Are there similar products offered by other manufacturers?
There are some breaker Independent Pole closing Operation (IPO) control method equipments by other manufacures, but the Inrush-Limiter T1 is Kodensya’s original equipment by breaker Three-Pole Simultaneous closing Operation (3PSO) control method as our patented unique idea.
What other solutions are there?
There are other methods that use a resistor serially connected to the circuit breaker, and a power generation system for excitation. The drawback is that the amount of installation space required and cost are proportional to the voltage class and capacity.
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