Brick Wall Series Mode AC Surge Suppressors/Powerline Filters 

How it WorksBrickwall AC surge protection uses NO MOVs

Most surge suppressor manufacturers make grand claims about their products but publish little of the technology involved.

We claim that our Brick Wall surge filters offer performance, reliability and safety advantages that are unparalleled by other surge protection products. The following represent the basic engineering principles.

Circuit Diagram of Brickwall AC surge protection

External surges first encounter the Series Mode surge reactor L1, and must pass through this reactor to reach the protected equipment. L1 resists the surge frequencies and immediately (zero response time) provides current limiting. The surge reactor behaves like a relatively high value resistor at the surge frequencies and dissipates some of the surge as heat. Unlike MOVs, TRANS-ZORBS and similar shunt elements that weigh less the 1/4 ounce, the Brick Wall surge reactor can easily absorb any surge repeatedly with absolutely no degradation.

The surge reactor in conjunction with the capacitor C2, restricts the incoming voltage slew rate of up to 5,000 volts per microsecond to a maximum of 100 volts per microsecond (1 volt per 10ns). L1 and C2 operate continuously and react instantly for surges or noise lying within the normal dynamic range of the power wave. If the surge exceeds the normal 180 volt peak dynamic range of the power wave, the dynamic clamp circuit (D1 C3) which tracks the peak of the power wave comes into play. With a diode clamp response time of 5ns, and maximum slew rate limited by L1 and C2 to 1 volt per 10ns, even a worst case surge will be clamped by the time the voltage exceeds the clamp voltage by 1 volt. The clamp circuit places a 180f capacitor (C3) in parallel with C2, reducing the surge slew rate to about 8 volts per microsecond.

Two 'crowbar' circuits act on high energy surges. The series connected crowbar circuits consist of a SCR switch, inductor and a 180f capacitor, chosen to minimize the disturbance on the power wave. The first crowbar circuit responds to the slew rate of the incoming surge. If a surge is large enough to generate more than 30 volts in less then 2s across C3, then the slew rate crowbar neutralizes the surge. Should C4 become charged, and the voltage again begins to rise, a second crowbar will activate at 220 volts peak to provide a final measure of protection.

Since the surge reactor is a high impedance at the high frequencies of the surge, minimal high frequency current flows in the neutral wire and consequently the 'common mode' problem created by simple shunt suppressors does not exist with Brick Wall products.

Our engineering staff is always available to answer any technical questions you may have. Computer simulations and custom configurations can be provided.

Click here for more information or to order

Return back to home page