POWER FILTERS FROM ARCOTRONICS
With its specialized feed-through filters for high-performance electronics systems, ARCOTRONICS offers solutions that meet the stringent requirements of medical, telecom, high-frequency welding and power supply applications, especially those used in EMI-critical installations!
ARCOTRONICS feed-through filters are designed to meet stringent requirements with respect to efficiency, compactness, high load capacity and attenuation performance inside a standard case. Their construction provides excellent separation between the input and output, as well as a highly effective means of preventing the bypass of interference signals at currents of up to 300A.
When supplying power to spaces that require the "purity" of a Faraday cage (e.g., medical and telecom equipment, etc.), such a power supply system can be implemented using the DU series of feed-through filters, for example. A central mounting capability for this cylindrical filter is provided with an M32 threaded bar and nut. Where central mounting is not possible, the DH series provides an alternative, as it is mounted with a rectangular flange that enables a 360° all-round contact to the housing wall of the space to be filtered using four M4 screws.
The connection to the current carrying central conductor can be made using a flexible cable equipped with a ring contact that matches the diameter of the central conductor (e.g., M6 for 40A). When connecting the cable, the lock nut must be held in position to avoid a torque of >50Nm (DU series) on the central conductor.
The DU and DH filter series are designed for an ambient operating temperature of -40°C to +85°C. Rated currents are specified for a temperature of 40°C and a humidity class of 56 days at 95% rel. humidity.
|
|
Prior to deciding which feed-through filter to use, it is necessary to review the capacitor safety requirements as well as the leakage current limits. As a result, it must also be known if the filter will be operated on a DC voltage, AC voltage or mains power network. Should the application require X2 or Y2-class capacitors, the differing application classes of the capacitors used in the DU and DH filter series need to be respected.
The technical documentation specifies the maximum leakage current values for each filter version. When using 3 feed-through filters with 3-phase loads the voltage between phases must also be respected. For example, in a star-type circuit arrangement of a 415V power network: 415/Ö3 = 240V. This means that a filter equipped with Y2-class capacitors and a rated voltage of 250VAC would be suitable for use. In addition, the operating leakage current in a symmetric network is very low, and the rated maximum value can only be reached if 2 phases are lost.
Due to the high capacitance values of these filters, in combination with their exceptional isolation resistance, a very high residual voltage may be present in the filters after disconnecting them from the power network. Adequate warning notices should therefore be provided! Automatic discharge circuits could be required to reduce the residual voltage to a safe level within the time frame specified by the equipment manufacturer.
For example, a 1Mohm discharge resistor that reduces the residual voltage to <50V within 1 minute after disconnection from the power network could be sufficient. In no case should the filter capacitors be discharged by shorting the capacitor elements, since the impermissibly high discharge currents generated could negatively influence the operating life of the filters.
The addition of external inductors will further improve the attenuation characteristics for low frequencies.
Use of these specialized, compact feed-through filters enables an individual mechanical arrangement that achieves the level of technical performance normally provided only by leading filters designed for shielded spaces.
I would be happy to provide you with more information!
Arnold Geitzenauer, EXT 24
|
