*I OFFER A DELTA LIGHTNING ARRESTOR AND SURGE CAPACITOR FOR WHOLE HOME PROTECTION
*BELOW IS INFORMATION FROM DELTA
CAUSES OF POWER SURGES
Electrical Power Surges range from small harmless occurrences to thunderous events that can cause extensive damage. Here is a review from small to large. Small harmless surges occur in electrical power systems almost continuously. A surge is a temporary sudden increase of voltage in the electrical circuit. In electricity, volts are the force that push electrical current through the circuit. Volts act like pressure pushing water current through a pipe. In electricity, the current is called amperes, amps, or, often just current.
Anytime electrical current flows through a circuit, a magnetic field builds around the flow of current. If one could see the magnetic field, it would look like rings around the wire that is carrying the current. Anytime that the flow of current is switched off, as when the refrigerator switches off, the magnetic field around the wire collapses on itself, inducing a voltage in the circuit. This voltage is a small surge. It happens for a moment, then it dissipates and is gone. These are the small harmless surges.
A large surge can occur when power to a neighborhood or other large part of the community is interrupted. Large currents being suddenly interrupted cause large surges. Power interruptions are caused when circuit breakers at power substations trip then automatically re-close. The breakers trip when shorts are caused by things hitting the power lines. Vehicles can hit poles, trees fall into lines, bird's wings short between lines, wind slaps lines together, etc. These cause the large surges that damage electrical equipment, appliances, and devices.
Still larger and more dangerous surges are caused by lightning. Lightning is a big surge in the sky. When it strikes on or near an electrical circuit it becomes a power surge that can damage any electrical equipment connected to the power system. Lightning, like any flow of electrical current, generates a circular magnetic field around it. Being a very large current, it generates a very large magnetic field, and therefore a large surge. Even if lightning only strikes near a power system, the magnetic field will induce a power surge in any nearby electrical system.
If lightning directly strikes a power line, it causes a direct surge as well as the magnetically induced surge. The only larger surge is the EMP. Any electromagnetic surge can be called an EMP, electromagnetic pulse, but the term is usually reserved for the surge caused by an atomic explosion. Where lightning's electromagnetic field is limited to a few hundred feet, that of a nuclear explosion can extend miles. If you are closer than that, you probably need not worry about the EMP.
So, small surges to a few hundred volts, are harmless. Harmful surges to a few thousand volts can cause damage to electrical equipment, appliances and devices. Larger surges, such as lightning, up to 50,000 volts will cause damage.
HOW ARRESTORS AFFECT SURGES
Surges are comprised of two elements: voltage and quantity of charge. A very high voltage surge can damage equipment by breaking down the insulating medium between elements in a circuit or between those elements and a ground. The amount of damage will be determined by the current from the charge and/or current from the power source. In order to protect a circuit from damage, a surge arrestor must conduct sufficient charge from the surge to lower the surge voltage to a safe level quickly enough to prevent circuit insulation from breaking down.
All circuits can withstand a high voltage for a short time. The shorter the time becomes, the higher the tolerable voltage becomes. Consider a fifty thousand volt surge impressed on a two-hundred-forty volt apparatus having a surge arrestor connected parallel. The surge arrestor will begin to conduct the charge, bleeding it out of the circuit. As the charge is removed from the circuit, the surge voltage will fall. As the charge approaches zero the surge voltage will approach zero. If this happens quickly enough the apparatus will be protected.
How quickly an arrestor can eliminate a surge from a circuit depends on four factors: the magnitude of the voltage, the quantity of the charge, the speed at which the arrestor starts conducting, and the conductivity of the arrestor. Given two arrestors, one having double the conductivity of the other, one will handle the surge twice as rapidly as the other. Given two arrestors of the same conductivity but one which begins to conduct more quickly, the quicker one will eliminate the surge from a circuit more quickly.
CLAMPING VOLTAGE vs. DISCHARGE VOLTAGE
There is no one clamping voltage for any arrestor. The clamping voltage will vary according to the amount of current being conducted, the internal resistance of the arrestor, the response speed of the arrestor, and the point in time at which the clamping voltage is measured. When a clamping voltage is specified, the current being clamped should be stated. For example, 500 volts at 1000 amps. Anytime there is a clamping voltage specified with no current there is no real meaning. If one uses a negligible current, such as one milliamp, any clamping voltage can be achieved. However, there is no protection afforded.
Consider a surge which rises from zero to fifty thousand volts in five nanoseconds, connected to an arrestor which starts to conduct at five nanoseconds, and clamps the surge to 500 volts in 100 nanoseconds. At any point in time during the one-hundred five nanoseconds, the clamping (discharge) voltage would be different. Even though the clamping voltage can be said to be 500 volts, if measured at twenty-five nanoseconds the clamping voltage would be above twenty-five thousand volts. An arrestor with a low ultimate clamping voltage might have a low conductivity which would cause the high voltage to exist in the circuit for a longer period of time. Arrestors with a high conductivity (low internal resistance) can conduct surges from the circuit more rapidly. Arrestors having a high current rating will have a high conductivity and will conduct a surge from the circuit more rapidly. The quicker a surge is eliminated, the more likely the equipment will be protected. Any reference to clamping voltage should always include the amount of current being clamped, and the clamping time.
HOW SURGE CAPACITORS WORK
A surge capacitor is a device designed to absorb surges and/or reduce the steepness of their wave front. A capacitor is able to absorb and hold a charge of electricity, returning it to the circuit at a later time. Since the surge capacitor is always connected to the power circuit, current flows at all times. When a surge occurs, added current flows to the capacitor thereby lowering the intensity of the surge voltage. The amount of current the capacitor can absorb depends on the size of the capacitor, and the amount of voltage pushing the current.
If the surge is of a low current relative to its voltage intensity, the capacitor will absorb it. If the surge has high current, the capacitor cannot absorb it.
By contrast, our lightning arrestor takes no current from the line during normal operation. When a surge occurs, the arrestor turns on to provide a discharge path. When the surge is gone, the arrestor turns off. The arrestor will handle unlimited amount of current, although amounts exceeding 100,000 amps will generally damage the arrestor.
The main advantage of a capacitor is that there is no time delay in turning on as it always conducts. The disadvantage is that the amount of current it can handle is limited to a few thousand amps, depending on the surge voltage. For this reason, an arrestor should always be installed with a capacitor to protect it from intense surges.
The continuous current flowing to a surge capacitor does not cause a waste of electricity. The capacitive reactanc cancels some of the inductive load, actually reducing the net power used by a fractional amount, thereby slightly reducing the power bill.
We offer three surge capacitors: 250 volt, single phase; 600 volt, three phase; 650 volt, three phase. An internal discharge circuit is provided. Mounting is facilitated by a three quarter inch nipple at the top of the unit. The black wires connect to the circuits, and the white wire connects to a ground. The housing is made of a non-conductive cylinder. Mounting brackets are available for each model of surge capacitor at an additional charge. They may be obtained by adding the part number MB to the end of the surge capacitor
*BELOW IS INFORMATION FROM DELTA
CAUSES OF POWER SURGES
Electrical Power Surges range from small harmless occurrences to thunderous events that can cause extensive damage. Here is a review from small to large. Small harmless surges occur in electrical power systems almost continuously. A surge is a temporary sudden increase of voltage in the electrical circuit. In electricity, volts are the force that push electrical current through the circuit. Volts act like pressure pushing water current through a pipe. In electricity, the current is called amperes, amps, or, often just current.
Anytime electrical current flows through a circuit, a magnetic field builds around the flow of current. If one could see the magnetic field, it would look like rings around the wire that is carrying the current. Anytime that the flow of current is switched off, as when the refrigerator switches off, the magnetic field around the wire collapses on itself, inducing a voltage in the circuit. This voltage is a small surge. It happens for a moment, then it dissipates and is gone. These are the small harmless surges.
A large surge can occur when power to a neighborhood or other large part of the community is interrupted. Large currents being suddenly interrupted cause large surges. Power interruptions are caused when circuit breakers at power substations trip then automatically re-close. The breakers trip when shorts are caused by things hitting the power lines. Vehicles can hit poles, trees fall into lines, bird's wings short between lines, wind slaps lines together, etc. These cause the large surges that damage electrical equipment, appliances, and devices.
Still larger and more dangerous surges are caused by lightning. Lightning is a big surge in the sky. When it strikes on or near an electrical circuit it becomes a power surge that can damage any electrical equipment connected to the power system. Lightning, like any flow of electrical current, generates a circular magnetic field around it. Being a very large current, it generates a very large magnetic field, and therefore a large surge. Even if lightning only strikes near a power system, the magnetic field will induce a power surge in any nearby electrical system.
If lightning directly strikes a power line, it causes a direct surge as well as the magnetically induced surge. The only larger surge is the EMP. Any electromagnetic surge can be called an EMP, electromagnetic pulse, but the term is usually reserved for the surge caused by an atomic explosion. Where lightning's electromagnetic field is limited to a few hundred feet, that of a nuclear explosion can extend miles. If you are closer than that, you probably need not worry about the EMP.
So, small surges to a few hundred volts, are harmless. Harmful surges to a few thousand volts can cause damage to electrical equipment, appliances and devices. Larger surges, such as lightning, up to 50,000 volts will cause damage.
HOW ARRESTORS AFFECT SURGES
Surges are comprised of two elements: voltage and quantity of charge. A very high voltage surge can damage equipment by breaking down the insulating medium between elements in a circuit or between those elements and a ground. The amount of damage will be determined by the current from the charge and/or current from the power source. In order to protect a circuit from damage, a surge arrestor must conduct sufficient charge from the surge to lower the surge voltage to a safe level quickly enough to prevent circuit insulation from breaking down.
All circuits can withstand a high voltage for a short time. The shorter the time becomes, the higher the tolerable voltage becomes. Consider a fifty thousand volt surge impressed on a two-hundred-forty volt apparatus having a surge arrestor connected parallel. The surge arrestor will begin to conduct the charge, bleeding it out of the circuit. As the charge is removed from the circuit, the surge voltage will fall. As the charge approaches zero the surge voltage will approach zero. If this happens quickly enough the apparatus will be protected.
How quickly an arrestor can eliminate a surge from a circuit depends on four factors: the magnitude of the voltage, the quantity of the charge, the speed at which the arrestor starts conducting, and the conductivity of the arrestor. Given two arrestors, one having double the conductivity of the other, one will handle the surge twice as rapidly as the other. Given two arrestors of the same conductivity but one which begins to conduct more quickly, the quicker one will eliminate the surge from a circuit more quickly.
CLAMPING VOLTAGE vs. DISCHARGE VOLTAGE
There is no one clamping voltage for any arrestor. The clamping voltage will vary according to the amount of current being conducted, the internal resistance of the arrestor, the response speed of the arrestor, and the point in time at which the clamping voltage is measured. When a clamping voltage is specified, the current being clamped should be stated. For example, 500 volts at 1000 amps. Anytime there is a clamping voltage specified with no current there is no real meaning. If one uses a negligible current, such as one milliamp, any clamping voltage can be achieved. However, there is no protection afforded.
Consider a surge which rises from zero to fifty thousand volts in five nanoseconds, connected to an arrestor which starts to conduct at five nanoseconds, and clamps the surge to 500 volts in 100 nanoseconds. At any point in time during the one-hundred five nanoseconds, the clamping (discharge) voltage would be different. Even though the clamping voltage can be said to be 500 volts, if measured at twenty-five nanoseconds the clamping voltage would be above twenty-five thousand volts. An arrestor with a low ultimate clamping voltage might have a low conductivity which would cause the high voltage to exist in the circuit for a longer period of time. Arrestors with a high conductivity (low internal resistance) can conduct surges from the circuit more rapidly. Arrestors having a high current rating will have a high conductivity and will conduct a surge from the circuit more rapidly. The quicker a surge is eliminated, the more likely the equipment will be protected. Any reference to clamping voltage should always include the amount of current being clamped, and the clamping time.
HOW SURGE CAPACITORS WORK
A surge capacitor is a device designed to absorb surges and/or reduce the steepness of their wave front. A capacitor is able to absorb and hold a charge of electricity, returning it to the circuit at a later time. Since the surge capacitor is always connected to the power circuit, current flows at all times. When a surge occurs, added current flows to the capacitor thereby lowering the intensity of the surge voltage. The amount of current the capacitor can absorb depends on the size of the capacitor, and the amount of voltage pushing the current.
If the surge is of a low current relative to its voltage intensity, the capacitor will absorb it. If the surge has high current, the capacitor cannot absorb it.
By contrast, our lightning arrestor takes no current from the line during normal operation. When a surge occurs, the arrestor turns on to provide a discharge path. When the surge is gone, the arrestor turns off. The arrestor will handle unlimited amount of current, although amounts exceeding 100,000 amps will generally damage the arrestor.
The main advantage of a capacitor is that there is no time delay in turning on as it always conducts. The disadvantage is that the amount of current it can handle is limited to a few thousand amps, depending on the surge voltage. For this reason, an arrestor should always be installed with a capacitor to protect it from intense surges.
The continuous current flowing to a surge capacitor does not cause a waste of electricity. The capacitive reactanc cancels some of the inductive load, actually reducing the net power used by a fractional amount, thereby slightly reducing the power bill.
We offer three surge capacitors: 250 volt, single phase; 600 volt, three phase; 650 volt, three phase. An internal discharge circuit is provided. Mounting is facilitated by a three quarter inch nipple at the top of the unit. The black wires connect to the circuits, and the white wire connects to a ground. The housing is made of a non-conductive cylinder. Mounting brackets are available for each model of surge capacitor at an additional charge. They may be obtained by adding the part number MB to the end of the surge capacitor
