Three phase harmonic filters from 1.1 to 250kW

Emis of Sweden has a range of three-phase passive harmonic filters intended to minimise harmonic distortion with non-linear loads such as variable frequency drives (VFDs), uninterruptable power supplies (UPS) and rectifiers.

EMIS TPQH3411 three phase mains filter

“They are typically tuned to specific harmonic orders – 3rd, 5th, 7th and 11th, for example – providing low-impedance paths at those frequencies to divert harmonic content,” according to the company, which is aiming at “maintaining THID in compliance with the current and voltage requirements of IEEE 519”.

“Capacitive elements in these filters offer reactive power compensation, enhancing the system’s power factor,” it added.


The family is called TPQH3411, and at a nominal 400V, its members range from a 1kW 3A load version weighing 9kg, to a 250kW version at 330kg.


In size, the range is 360 x 160mm by 220mm tall, to 1.4m x 550mm x 600mm tall. Beyond this are minimum air gap requirements at the ends and sides.

1.6x over-load is possible for one minute once per hour, and efficiency is >98% at rated voltage and power.

At 11kW and upwards, airflow is required – up to 820m3/hour for the largest filter. With this, operation is over -25 to +45°C.

Input requirements are three-wire three-phase 50Hz at 380 to 415Vac. TN, TT or IT earthing is possible. Isolation is rated at 2,160Vac for 1s.

Find the three-phase filter family on this Emis web page.

Schurter has DIN rail three-phase mains filters

Steve Bush

Steve Bush is the long-standing technology editor for Electronics Weekly, covering electronics developments for more than 25 years. He has a particular interest in the Power and Embedded areas of the industry. He also writes for the Engineer In Wonderland blog, covering 3D printing, CNC machines and miscellaneous other engineering matters.

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