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Grafik Line side Branche Antriebstechnik

Line reactors reduce low-frequency disturbances (harmonics) and reduce the strain on the mains supply by compensating for the distortion reactive power. Limiting the start-up current protects the connected consumers and thereby also increases their lifetime. The standard product range includes series with short circuit voltages of 3%, 4% and 5%.

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Kurvengrafik zum Netzstrom bei Filtern

Passive harmonic filters from BLOCK reduce harmonic currents and thereby also reduce the distortion reactive power because they are precisely aligned with the main harmonics frequencies. The quality of the power signal is stated as a percentage with the THDi value (Total Harmonic Distortion). While a THDi of 30 – 40% is achieved with a line reactor in standard industrial applications, BLOCK harmonic filters can reduce the THDi to <= 7%. In this way, in addition to improving the Power Quality, BLOCK harmonic filters also contribute towards mains stabilization.

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Grafik Motor side Branche Antriebstechnik

Motor reactors protect the motor from high edge steepness of the frequency inverter output voltage. High edge steepness at the motor occurs through an upswing in the pulse width modulated voltage at the output of the frequency inverter via the capacitance per unit length of the connected motor cable. The longer the motor cable the higher the capacitance per unit length – and therefore the higher the expected edge steepness at the motor. This is stated as a dv/dt value and results in a gradual increase in voltage. A dv/dt value of >2 kV/µS is achieved if no filters are used. This can cause insulation damage and even total failure, particularly with older motors or motors with efficiency classes IE1 and IE2. Motor reactors reduce the dv/dt value to up to <500V/µs for motor cable lengths of up to 100 meters. A dv/dt value of <250V/µs is also feasible with long cable lengths >100 m when a dv/dt filter is used with additional filter components, such as small capacitors and resistors.

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Sine filters produce a sinusoidal voltage featuring low distortion from the switched frequency inverter output voltage. The sine filter achieves a very high filter effect through precise low-pass tuning to the switching frequency of the frequency inverter. The useful signal (motor operating frequency) passes through the sine filter with a minor effective drop in voltage, while the switching frequency is reduced by approx. 90%. Switching frequency harmonics are almost entirely filtered out. The use of sine filters enables the use of long shielded motor cables and ensures low noise motor operation.

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Kurvengrafik zu hochfrequenten Störaussendungen
Kurvengrafik zu allpoligen Sinusfiltern Spannung Phase-Ground

All-pole sine filters combine the benefits of a regular sine filter with additional filtering of the common-mode components which cause bearing currents at the motor, excessively high leakage currents, and EMC problems in the plant. BLOCK’s concept for all-pole sine filters provides for an additional connection to the intermediate circuit of the frequency inverter. This means that common-mode currents are returned directly to the source, i.e. the intermediate circuit of the frequency inverter. Further benefits:

Reduction in bearing currents
Very long, unshielded motor cables can be used
EMC optimization
Reduction in filter components on the mains
Reduction in leakage currents
Flawless operation on FI circuit breakers

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All-pole sine filter SF4
Line Reactor LR3-A
Sine filter SF3-A (in development)