Arteche tuned harmonic filters divert harmonic energy away from the power source (which is common to other loads) and localize the flow of harmonics to that part of the electrical system which is between the harmonic producing load and the filter. Their automatic (switched) harmonic filters are able to measure the power factor and harmonic distortion for a system and use contactors to switch multiple filter networks into or out of the circuit. This maintains acceptable harmonic distortion without over compensating the power factor. Arteche also offers a dynamic response harmonic filter that are similar to the automatic harmonic filters except switching is accomplished by the use of Thyristor technology as opposed to electromechanical contactors. This enables the filter to be inserted into the electrical system in as little as one-half cycle (8-10 milli-seconds).

ABB's CHARM harmonic filters come in three models; the BP, HP or C. These filters have a voltage rating of 1-500 kV, a power rating of >1 Mvar, a fundamental frequency of 50 or 60 Hz, the tuning frequency is optional and they can be installed indoor or outdoor. Spec sheet

AFP Transformers manufactures custom Harmonic Filter Inductors for the power factor correcting and harmonic suppression industry. Harmonic filter inductors range from small single or three phase, low voltage units to large single-phase devices used in medium voltage applications. AFP’s Harmonic Filter Inductors use copper windings, less than 20% of watts loss as a result of fringing, inductances tuned to specifically match capacitor KVAR ratings, and balanced core and coil heating.

AIM Europe manufactures active harmonic filters that incorporate harmonic mitigation, reactive current control, load side transient suppression, load side surge suppression, and reduces the effect of supply sags and surges or flicker. Units are available in 208V - 600V 3Ph 3W or 4W 50/60Hz, 110V - 240V. 1Ph 50/60Hz (up to 25 A), 25 to 400 A harmonic current in a single unit, up to 1000 A in multi-parallel form, and harmonic current attenuation up to the 51st harmonic.

Amtech Drives offers active and passive harmonic filtering. The Amtech active filter offers harmonics suppression, power factor improvement, imbalance compensation and voltage stabilization. Their passive harmonic filter system is designed to suit industrial applications for harmonic filtering. This passive filter can be customized as per the harmonic pattern, is most suitable for fixed non-linear loads, and also results in power factor improvement.

The Avtech Active Filter is connected in parallel with the AC line and constantly injects currents that precisely correspond to the harmonic components drawn by the load.  The result is the power bus remains sinusoidal. These filters cancel primarily the 3rd, 5th and 7th harmonic frequencies and provide up to eight amps of harmonic cancellation current.

BPC manufactures active harmonic filters that improve power quality, reduce overloading of cables, motors and transformers, inject equal and opposite harmonic currents from 3rd – 31st, have 25-200A ratings 3 and 4 wire, and has voltage ratings  208-480 at 50/60Hz.

The BPEC rectifier system computer analysis program was developed to accurately design the PF correction and harmonic filtering equipment required to meet the customer's PF requirements and harmonic distortion limits.  Once the customer's AC supply system parameters and the load operating points are provided, the computer analysis will determine the required amount of capacitive kVAR needed to correct the power factor at the operating conditions and, also, determine the filters needed to meet the harmonic distortion limits.

The Danfoss AHF 005 and AHF 010 are advanced harmonic filters designed to match the Danfoss frequency converters. By connecting the Danfoss harmonic filters in front of a Danfoss frequency converter the harmonic current distortion generated back to the mains is reduced to a minimum. Danfoss has developed an Advanced Harmonic Filter that offers superior performance to complex 12 & 18 pulse VFD’s.

Eaton's Cutler-Hammer fixed passive harmonic filters utilize capacitor cells that are connected with a tuning reactor so that dangerous resonance conditions are avoided. Fixed capacitor banks are tuned to the 4.7th harmonic and will reduce levels of the 5th harmonic, helping your facility meet the IEEE 519 standard. Their switched passive harmonic filters offer a slightly different mode of operation. As loads change throughout the facility, the solid state controller will add or subtract capacitance from the system to maintain a consistent level of desired power factor. Eaton's active harmonic filters will monitor the distorted electrical signal, determine the frequency and magnitude of the harmonic content, and then cancel those harmonics with the dynamic injection of opposing current.

Elspec offers tuned and de-tuned harmonic filtering. In de-tuned systems, reactors are installed in series with the capacitors. This prevents resonance conditions by shifting the capacitor/network resonance frequency below the first dominant harmonic (usually the 5th). In tuned systems, the capacitor/reactor filter is tuned to absorb particular harmonics and reduce the THD (Total Harmonic Distortion).

Flann Microwave offers tunable harmonic filters, fixed and tunable harmonic filters, and low pass harmonic filters. Flann has redesigned their fixed filters with new tuning techniques to derive mechanically tuned filters. This tuning technique provides high reliability with a sustained repeatable performance. Flann has also re-engineered their range of low pass harmonic filters to extend the frequency of operation to 110GHz. All of these low pass filters provide better than 40dB rejection up to the 3rd harmonic over the full waveguide band. VSWR is better than 1.5 over the pass band. Insertion loss is less than 1.5dB. Tunable filter spec sheet. Low pass filter spec sheet.

GE's Matrix harmonic filters have a standard feature of <8 % current distortion (at full rated load). They also have available an optional feature of <5 % current distortion (at full rated load). These harmonic filters are suitable for use on multiple inverter/drive applications and can be used with stand-by generators.

Gilbert Electrical Systems manufactures harmonic filter/capacitor banks, 480 volt to 35KV. They will analyze the customers’ needs and provide a well engineered system that will satisfy their power factor and harmonic problems. Gilbert has furnished many custom designed passive shunt harmonic filter packages.

Harmonics Limited is a leading provider of Harmonic Suppression Systems (HSS). Their patented harmonic mitigation technology actually prevents equipment from generating third-harmonic currents instead of just filtering the harmonics that are already there. Their GeneratorMax system is a passive, tuned harmonic blocking filter. When it is tuned to 180Hz (the 3rd harmonic in a system with a 60Hz fundamental frequency), the filter has a low impedance at the fundamental and an almost infinite impedance at the 3rd harmonic.

Intelligent Solutions' Times One active harmonic filter series offers power factor correction (up to 100%), reduces operating temperatures of electrical systems, reduces harmonic distortion to less than 5% for the ITHD and VTHD, and protects against destructive transients.

MEDCOM Series FA and FA3 active harmonic filters are used to compensate for current distortions in the mains caused by devices with non-linear current-voltages. These active harmonic filters can be connected in parallel to the non-linear device, in either one phase or three phase networks. The three phase unit (FA) reduces distortion in the mains below 5%. The use of these units enables reduction of harmonic distortions in line current, reduction of the peak value of the line current, reduction of rms of the current, and reduction of the start-up current during switching on the load. Spec sheet

Mesta Electronics offers the Digital Power Manager (DPM), an active harmonic filter that reduces harmonic distortion to less than 5%, instantly reacts to and corrects varying load conditions, and improves the power factor to the plant utility grid. Current ratings available at 480 V are 50 amps, 100 amps, 150 amps, 200 amps and 300 amps. Spec sheet

Mirus International offers a wide variety of harmonic filters. The Lineator AUHF is a passive filter capable of reducing Variable Speed Drive (VSD) / Variable Frequency Drive (VFD) harmonics by up to 10 times. The Lineator 1Q3 is a passive harmonic filter designed for 3-phase VFD's operating on a 1-phase supply. The Harmony Series isolation transformers combine very low zero sequence impedance outputs with phase shifting for effective harmonic mitigation. The Onics Series offers two types of harmonic mitigating panel boards. The Eliminator Series offers three models of series connected, 3-phase, 3-wire, phase shifting auto-transformers for control of 5th and 7th or 11th and 13th harmonics in 3-wire circuits with no neutral conductor. The Drive Series transformers are phase shifting isolation transformers designed to produce cancellation of the characteristic harmonics of 3-phase rectifiers to produce effective 12-pulse 18-pulse, and 24 pulse schemes.

MTE Matrix Filters are used to solve harmonic distortion on six pulse rectifiers. These power supplies are found in three phase electronic equipment such as adjustable speed motor drives, welders, battery chargers, servo drives and other equipment. On AC variable frequency, variable torque drive applications (fans & pumps), these passive harmonic filters will meet the maximum levels of THID (total harmonic current distortion) from no load to full load. Spec sheet