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What is difference between breakdown voltage and dielectric strength of transformer?
Wiki User
∙ 10y ago
The dielectric strenght of a transformer represents the maximum voltage permissible to apply across the transformer insulation i.e. between the transformer winding to another part of the transformer, normally the chassis or another winding and without break-down of the insulation ocurring (e.g. arcing).
The breakdown voltage of a transformer represents a voltage that exceeds its dielectric strenght and that causes breakdown e.g. arcing across the insulation.
Wiki User
∙ 10y ago
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Which is another name for dielectric strength test?
ASTM D149 - 09 Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
What is Dielectric breakdown strength of air?
3KV/mm or 3X10^6 V/M
What is BDV test for distribution transformer?
When you say BDV you might mean the dielectric strength of transformer oil. A new transformer oil should have at lest a dielectric strength of 39 KV. from a British standard.Transformer oils used are normally tested using ASTM D877-82 with the KV strength tester using 1" electrodes spaced 0.1" apart and the test voltage increased at 3,000 volts/min until it breaks down. The average Kv obtained after 8 trials is considered the Oil dielectric strength.Using this test method,dielectric strength at 30 kv and above is considered good. Dielectric strength between 23 to 29Kvis considered usable, but requires filtering. Below 23 kv, the transformer oil should be replaced.Another method ASTM D18747-82 uses the small radius electrodes but spaced only .o4 inches. The test voltage is 500volts/min and increased until breakdown. The dielectric strength is still the average Kv obtained in 8 trials. The dielectric strength of 28-29Kv is considered good. Below 28 kv, the transformer oil is usable but requires filtering. The latter method is considered a better test method
WHAT will happen if you run oil transformer with out oil?
As well as providing a cooling medium, transformer oil is also used to insulate a transformer. As its dielectric strength (how well it insulates) is much higher than air, it means that components within a transformer that are at different potentials can be placed much closer together if they are immersed in oil. So, operating an oil-filled transformer without oil will likely cause insulation breakdown within the transformer.
What is meant by transformer charging?
Most likely this is referring to the initial inrush that occurs when a transformer is energized. The core of a transformer is designed for a specific magnetic field strength; When a transformer is switched into a circuit, it usually will not be switched at exactly a voltage peak. When the voltage is at its' peak, the induced magnetic field will be at zero. If the switching occurs at a voltage zero, the magnetic field strength will attempt to climb to double the designed value; since the transformer core is not generally oversized to this degree, it will saturate. This causes large inflows of current to the transformer, and shows up as even harmonics (mainly second harmonics) in the current waveform. This settles out within a few seconds (generally) to a small energizing current, usually less than 1% of the transformer's rated current.
What is the dielectric breakdown strength?
This depends on the particular dielectric. Each has a different breakdown strength.
What is dielectric breakdown?
The dielectric breakdown strength is 3,000 volts per millimeter.
How does the moisture and temp effect the breakdown strength solid dielectric?
Generally, increased moisture levels will lower breakdown strength, especially if the dielectric readily absorbs water. Increasing temperature generally decreases breakdown strength of solid dielectrics. The dielectric strength of some materials may increase with temperature within limited temperature ranges. However, dielectric strength eventually begins to decrease at higher temperatures.
How can you test the dielectric strength of oil of transformer?
dielectric strength is tested by transformer dielectric strength oil testing machine. at first, oil which is to be tested is pour near the two electrode. both the electrode should be dipped in oil . then adjust the distance between the electrode .now start the machine.when a sound came from machine then note down the dielectric strength of the oil.
Difference between insulation resistance and dielectric strength?
INSULATION RESISTANCE: The insulation resistance is a measure of the capability of a material to withstand leakage of current under a Vdc potential gradient. DIELECTRIC STRENGTH: The dielectric strength is a measure of the ability of the material to withstand a large field strength without electrical breakdown, and is usually expressed in volts per mil (.001') or volts per cm of dielectric.
Which is another name for dielectric strength test?
ASTM D149 - 09 Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
How can you find dielectric strength of oil in transformer?
by spark gaps immersed in the oil sample
How does humidity affect the dielectric breakdown strength of air?
Generally, dielectric breakdown strength decreases with increasing humidity. In air, exact relationships between dielectric strength and humidity are hard to derive, due to the numerous other variables compounding the relationships (e.g. electrode size and shape, air temperature and pressure). Sources: http://www.scienceforums.net/topic/37206-dielectric-strength-of-air/ http://en.wikipedia.org/wiki/Dielectric_strength
What is Dielectric breakdown strength of air?
3KV/mm or 3X10^6 V/M
What is BDV test for distribution transformer?
When you say BDV you might mean the dielectric strength of transformer oil. A new transformer oil should have at lest a dielectric strength of 39 KV. from a British standard.Transformer oils used are normally tested using ASTM D877-82 with the KV strength tester using 1" electrodes spaced 0.1" apart and the test voltage increased at 3,000 volts/min until it breaks down. The average Kv obtained after 8 trials is considered the Oil dielectric strength.Using this test method,dielectric strength at 30 kv and above is considered good. Dielectric strength between 23 to 29Kvis considered usable, but requires filtering. Below 23 kv, the transformer oil should be replaced.Another method ASTM D18747-82 uses the small radius electrodes but spaced only .o4 inches. The test voltage is 500volts/min and increased until breakdown. The dielectric strength is still the average Kv obtained in 8 trials. The dielectric strength of 28-29Kv is considered good. Below 28 kv, the transformer oil is usable but requires filtering. The latter method is considered a better test method
What happens when dielectric breakdown occurs?
The dielectric,usually the insulator between the plates of a capacitor, can be overstressed by the application of too high voltages applied to the capacitor plates. The dielectric breaks down and a current flows between the plates until,either they are discharged, or an equilibrium is reached,below the working voltage of the capacitor. If the dielectric is damaged in this process he capacitor must be replaced. Some dielectric material self heal and can recover from an over voltage.
What is dielectric strength?
The dielectric strength refers to the maximum working voltage that a material can withstand without breaking down. At breakdown the electric field frees bound electrons turning the material into a conductor.
