• No Sacrificial or Wear Components, 
  No MOV's, NO SURGE PROTECTOR FAILURES
• No Surge Diversion To Ground
• Exceptional Powerline Filtering
• Fastest Surge Protector Response Time
• Lowest Surge Protector Clamping Level
• Lowest Surge Protector Let-Through Voltage

How it Works

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.

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 MOV’s, 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 180µf 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 180µf 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 2µs 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.

There is  a bridge circuit which adds additional filtering if  surge voltage exceeds the power wave voltage, either positive or negative.

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

NO FAILURES

TESTED BY UL TO ONE THOUSAND SURGES OF 6000V, 3000A

We believe that a surge protection device should not fail. At the heart of our Series Mode Surge Filter is a massive inductor (photo below). This is not a sacrificial component. It will never fail. It will not degrade with use. In fact no component used in the construction of this product is sacrificial. A Brick Wall Surge Filter will never experience a surge related failure.

You do not have to take our word for it. Consider the following:

IEEE (The Institute of Electrical and Electronic Engineers) states that 6000V is the largest transient that the interior of a building would experience.

IEEE defines its harshest interior surge environment as one that could experience 100 surges of 6000V, 3000A in a years time (category B3).

A new federal guideline recommends that a surge protector utilized in a harsh environment should be capable of withstanding 1000 surges of 6000V, 3000A or ten years worth of IEEE’s category B3.

UL (Underwriters Laboratories) now provides a new adjunct testing service (in addition to the 1449 safety classification) that will test to the 1000 surge, 6000V, 3000A federal protocol.

Passing such a test is a virtual guarantee that a surge protection device will never experience a surge related failure.

Early in 1996 UL applied 1000 surges (at 60 second intervals) of 6000V, 3000A to an off-the-shelf Series Mode Surge Filter.

There was no failure. There was no performance degradation. Let through voltage did not exceed 290V. Certified by UL.

You cannot do any better than this for a building interior surge suppressor.

Reliability is usually the number one parameter for selecting a surge protection device. Unfortunately most of what is available is not very reliable. Surge suppressors are notorious for failing.

MOV’s: SACRIFICIAL BY DESIGN

MOV’s are the mainstay component of the surge suppression industry. For certain electronic applications they are an excellent choice. AC power line surge suppression is not one of them. MOV’s function by creating a short circuit (usually to the neutral and the ground) when a preset voltage threshold is exceeded. Essentially they divert surge current away from what is being protected. Unfortunately MOV’s are sacrificial components. This means that the performance life of any surge protection device utilizing this technology is finite. With every surge current diversion above a modest level an MOV comes closer to its inevitable end.

JOULE RATING/SURGE CURRENT LIMITATIONS

The joule rating of any MOV is a measure of the amount of energy it can absorb at one time without failing. With an MOV this level declines with use. When exceeded it can cause an explosion or a fire. In a harsh, lightning prone environment this limit can easily be reached. Our massive inductor limits current (hence voltage) and has no real world surge current/joule rating limitations. The product can withstand the harshest surge environment indefinitely.

THERMAL RUNAWAY (FIRE)

Clamping threshold is the voltage level where the MOV activates. Typically it is set around 220V at 1 milliamp current. With the peak of the sine wave normally at 172V, a surge of only an additional 50V will activate that MOV. Just as repeated usage causes the joule limit of an MOV to drop it can also cause the clamping level to do the same. Eventually the clamping point can fall below the peak of the normal sine wave. In essence the MOV turns on with every cycle of the powerwave and experiences thermal runaway (fire). This characteristic of an MOV made them totally unacceptable to our engineers. Our surge protection products do not utilize MOV’s and have none of their inherent limitations. Brickwall Surge Filters will not catch on fire.

DEMAND UL ENDURANCE TEST RESULTS

The mechanisms are now in place for a manufacturer of a surge protection device to certify a product to very exacting specifications. Ask to see the UL test results that certify a product to 1000 surges of 6000V, 3000A.

POWER LINE 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. Series Mode is a power filter technology; it provides exceptional powerline filtering.

POWERLINE FILTERING

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 Filter makes for superb powerline filtering characteristics, even in non-surge applications.

FULLTIME POWERLINE FILTERING

Being a passive component, the series inductor is always operational. A 2µf capacitor is also always active. Attenuation: 3db @ 3kHz, 38db @ 100kHz, >50db @ 300 kHz.

POWERLINE FILTERING UNDER A SURGE CONDITION

In a powerline surge situation up to three additional dynamically inserted 180µf electrolytic capacitors come on line(Figure 2). A Brick Wall surge filter 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 on the left indicates the filtering characteristics of Brick Wall Surge Suppressors/ 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 the unit 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.

New Performance Standards

INSTANTANEOUS RESPONSE TIME

The heart of our units is the inductor. This is a passive component that is in series. It does not
have to 'turn- on' and it represents the only path the surge current can take to get to the load. It
reacts instantaneously. Almost all other surge protection devices are in parallel. After a certain
voltage threshold is reached the shunt elements create a short circuit diverting the surge current
away from the load. In effect it is a switching device. Any switch, no matter how good, is going to
take time to go from an opened to a closed position.

CLAMPING LEVEL 2 VOLTS ABOVE THE SINEWAVE PEAK

MOV’s are preset to clamp at certain voltage thresholds (usually around 220V). The
manufacturers walk a fine line here because too low a level and the MOV turns on more and
wears out sooner. Too high a level and more unwanted current has access to the load. Even
more importantly, marketing rhetoric is sacrificed. Our Series Mode device has active tracking; a
180µf electrolytic capacitor constantly tracks the sinewave peak, whatever the powerline voltage.
Any rise above this reference level is immediately clamped to this level.

LET THROUGH VOLTAGE <300V

Voltage that gets by a surge suppression device to the load is called the let through voltage. The
lower the let through voltage the better. The above oscilloscope trace of a Brick Wall product
shows a let-through voltage of 192V for a 1200V transient. That represents an additional 20V
above the sinewave peak (the sinewave peak is normally 172V). UL endurance tested the
product with one thousand 6000V surges and the let through never exceeded 290V (290V is the
approximate let through voltage an MOV-based device would experience at 1200V). We believe
this represents the lowest let through voltage in the industry.

SLEW RATE

Slew Rate is the rate of change of voltage in volts per microsecond. The faster the slew rate the
more readily the overvoltage will couple to nearby datalines. Notice the ascending slew rates of
the photographed oscilloscope traces. This is representative of the voltage that 'hits' the load
before clamping. A quick rise such as this can represent quite a 'jolt' to the equipment. The trace
of our unit shows a negligible slew rate. Again, we believe this represents a new industry
standard.

There is  a bridge circuit which adds additional filtering if  surge voltage exceeds the power wave voltage, either positive or negative.

The Consequences of Diverting Surge Current to Ground

Almost all manufacturers of shunt mode devices (those utilizing MOV’s) design their products to divert surge current equally between the ground and neutral wires. A surge suppression device should not divert surge current to the ground wire.

DATA LINE PROTECTION?

Our sales staff repeatedly hears this same story: It seems a company has experienced considerable surge damage to electronic equipment. The shunt mode surge suppression devices would appear to have done their job by protecting the loads from the front end (power line). The damage, in their estimation, resulted from surge current that traveled down the data lines. How do they know this? All the damage appears to have originated at the data ports, hence they conclude that the surge must have traveled this route. Their solution: They need data line protectors.

They are right in as much as the damaging current did propagate through the data lines. However, damaging surges do not originate in dataline circuits.

Their systems do not need data line surge protectors. Interconnected systems need powerline surge protectors that do not divert surge current to the ground wire.

INTERCONNECTED SYSTEMS AND GROUND LOOP CONTAMINATION

Interconnected (networked) systems, so prevalent in today’s commercial/industrial world, have made shunt mode technology (origins 1972) inappropriate. Equipment sharing common power and data lines form circuits between themselves via the ground wire (both referenced at the load). What does current do in a closed circuit? It flows. A powerline surge diverted to the ground wire will make its way to the chassis, through the motherboard (which is also grounded at the chassis), onto and through the data lines (which use the powerline ground as a voltage reference and are also connected at the motherboard) and to the data ports of the rest of the connected system. This is how most data line surges originate.

DATA LINE NOISE

Smaller surges diverted to ground wires may not immediately damage equipment (though the cumulative effect can eventually cause failures). On the other hand, low level surge current diverted to the data lines (via the ground wire) can immediately scramble data, slow down data transfer and cause mis-operations or lock-ups as a consequence of its effect as system noise (unwanted current on the data lines).

SERIES MODE TECHNOLOGY

Brick Wall products are based on the current (hence voltage) limiting of a massive inductor. Residual energy that leaks through is captured by a series of electrolytic capacitors. There it is slowly leaked back to the neutral at a harmless level. Outside of trivial amounts of parasitic capacitance our Series Mode devices do not put any surge current on the ground of your systems. Engineers of an MOV based surge suppressor face the dilemma of what to do with potentially large amounts of surge current. They don’t want to overload the neutral and want to prolong the life of the MOV. Using two of these elements and diverting equally between the ground and neutral wire prolongs MOV life and prevents overcurrent on the neutral. Series Mode technology presents no such dilemma.

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