Powerline Filtering: The Technical Side Of It
Brick Wall Surge Protectors Provide Exceptional Powerline Filtering
System Noise
Electronic noise is undesirable low level high frequency signals found on the powerlines and/or datalines. It is often the cause of scrambled data, slow data transfer, mis-operations and lock-ups. Its long term cumulative effect can eventually cause hardware failure. Our surge protectors use Series Mode power filter technology. Brick Wall Surge Protectors provide exceptional powerline filtering.
Powerline Filtering
In a Brick Wall Surge Protector, powerline noise first encounters a series inductor (choke). The inductor will act as an open circuit to higher frequencies and a short circuit to lower frequencies. The higher frequencies that do leak through then encounter a series of dynamically inserted capacitors. Here the opposite takes place. The capacitors act as short circuits to higher frequencies and as open circuits to lower frequencies. The capacitors will return the noise and any surge current slowly (harmlessly) to the neutral. The dual filtering aspect of a Brick Wall Surge Protector makes for superb powerline filtering characteristics, even in non-surge applications.
Fulltime Powerline Filtering (Figure 1)
Being a passive component, the series inductor in our surge protector is always operational. Also a 2µf capacitor is always active. Attenuation: 3db @ 5kHz, 26db @ 100kHz, 38db @ 300 kHz.
Powerline Filtering Under a Surge Condition (Figure 2)
In a powerline surge situation up to three additional dynamically inserted 180µf electrolytic capacitors come on line. Brick Wall surge protectors will interpret any two volt rise above the peak of the sinewave, regardless of powerline voltage, as a surge condition. A small powerline voltage fluctuation will activate this capacitor arrangement. Attenuation: 8db @ 100Hz, 28db @ 1kHZ, 46db @ 10kHz, >70db @ 100kHz (50 ohm).
The graph below indicates the filtering characteristics of Brick Wall Surge Protectors/ Powerline Filters. Line 1 represents the filtering provided by a massive inductor in conjunction with a 2µf capacitor. This attenuation is provided under normal operating conditions. The dynamic clamping characteristics of our surge protectors sees any 2 volt rise above the peak of the sinewave as a surge condition. This will activate the first 180µf electrolytic capacitor (Line2). If the surge energy continues to rise two more electrolytics dynamically come on line (Lines 3 & 4) providing even greater noise attenuation.
