Ally Winning, European Editor, PSD
Three-phase filters are a necessary component in many applications, particularly in the industrial and medical areas, to ensure circuits operate without interference, reducing errors. Currently, they tend to be bulky, grey boxes which may need quite a bit of engineering work to perform their task correctly. They can also be expensive, and since they are a component that does not add anything to the overall design except to the price and volume, many companies are looking for ways to cut the engineering time and cost required to implement them to a minimum. Filter manufacturers may see the value in helping their larger customers with designs, but more often than not, those customers that require smaller volumes are left to their own devices.
Now, thanks to advances in materials, Kemet has launched a range of standard, off-the-shelf three-phase filters that cut the size of the solution considerably, while giving designers a variety of options. The GTX series of metal box three-phase filters use the same nanocrystalline metal for their cores that the company uses in other applications, such as inverters. Kemet has also used the material in its range of single-phase EMI filters that was launched last year. The nanocrystalline material has much better performance than traditional ferrite filter cores. Its higher magnetic permeability, means that it can either offer a solution with greater noise absorption, or it can offer similar performance to ferrites, but in a much smaller package. The other advantage of the nanocrystalline material is that it holds up better under higher temperatures, with much less performance degradation.
The series fulfils the growing need for EMI-RFI filters to suppress electromagnetic conductive noise in a number of applications, while being able to meet three-phase EMC requirements with a wide variety of characteristics. The GTX filters achieve excellent damping and attenuation characteristics in a small size and a wider frequency range. Six different combinations of Y capacitors can be selected to support various equipment topologies, meaning there is less need for customisation after the filters have been purchased. The filters are compact and lightweight due to their high mechanical density.
The GTX series is rated to 500 VAC (50/60 Hz), 500 VDC (250 VAC, 353.3 VDC for c-UL) and the filters can operate in a temperature range from -25°C to +55°C. The nanocrystalline metal core results in rated currents of 30 A to 60 A. GTX is safety-certified by UL, c-UL, TüV and is RoHS as well as REACH compliant. These filters comply with EU RoHS Directive 2011/65/EU and (EU)2015/863. The new filter family is intended to suppress the noise in electronic equipment with superior attention characteristics for applications such as machine tools, industrial robots, wind-power generation, power storage systems, medical equipment, and diagnostic instruments.