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Inrush is due to the saturation of the core of the transformer.
When the highside device closes to energize the transformer, it does not always do so right at a voltage peak. The transformer core B (magnetic field) will be 90 degrees out of phase with the applied voltage, so a peak voltage close is ideal. Once it is closed, the B will continue up and down 90 degrees out of phase with the voltage. Assuming there is no residual magnetic field (B starts at zero), it will be offset by the initial non - peak close. This offset in magnetic field will cause the core to go into saturation; depending on the core design it may be further or less into saturation on different Transformers.
When the core saturates, large currents flow, and these currents (normally) have a high 2nd harmonic component which is used in protective relaying to restrain for inrush.
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What is the difference between the inrush current and the fault current?
Magnetizing inrush current has bigger 2nd harmonics compare to short circuit current. the second harmonics content is about >60% of fundamental harmonic. magnetizing inrush current happened when we energised the transformer, and short circuit current happened if there is a short circuit between different alive phase.
Does a transformer draw a lot of current when first connected to a source?
Yes it does as it is an Inductor and an Inductor needs to build up a magnetic field. It is called INRUSH current.
What does the term VA mean when applied to a control transformer?
VA refers to the effective load that is placed upon the Control Transformer (also known as Selection Inrush VA).
Why does a three phase transformer not short itself out when the phases are connected through the transformer?
I asked this very question to my professor in electronics 101 in college! He explained to me the load side of the transformer if not connected to any load is open. This is a great resistance to completing the circuit. This is transferred to the primary side of the transformer as a great resistance thus no current flow.
How is current controlled in welding transformer?
in welding machine, the transformer used is basically a current transforrmer. so by changing the tap of secondary side of transformer, we can increase or decrease the current in the transformer.
Magnetic inrush current in power transformer with waveforms?
The mgnetic inrush current is the current drawn by the transformer when power is applied to the primary winding
Magnetic inrush current in power transformer?
When a transformer is initially connected to a source of AC voltage, there may be a substantial surge of current through the primary winding called inrush current. Inrush current can be up to ten times higher than the continuously needed current because there is low initial resistance.
What is the difference between the inrush current and the fault current?
Magnetizing inrush current has bigger 2nd harmonics compare to short circuit current. the second harmonics content is about >60% of fundamental harmonic. magnetizing inrush current happened when we energised the transformer, and short circuit current happened if there is a short circuit between different alive phase.
Does a transformer draw a lot of current when first connected to a source?
Yes it does as it is an Inductor and an Inductor needs to build up a magnetic field. It is called INRUSH current.
What are the factors affect the magnitizing inrush current in power transformer?
1- residual flux existing before enegizing the transformer . 2- size of transformer . 3- size of power system. 4- type of magnetic material of the core. 5- the method of energizing the transformer.
What is the inrush current for halogen?
the answer ur looking for is incandescent
What does the term VA mean when applied to a control transformer?
VA refers to the effective load that is placed upon the Control Transformer (also known as Selection Inrush VA).
Why does a three phase transformer not short itself out when the phases are connected through the transformer?
I asked this very question to my professor in electronics 101 in college! He explained to me the load side of the transformer if not connected to any load is open. This is a great resistance to completing the circuit. This is transferred to the primary side of the transformer as a great resistance thus no current flow.
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 meant by current chopping?
When low inductive currents, such as magnetiing current of transformer, shunt reactors are interrupted by breaker, there is rapid deionization of contact space and may cause the current to be interrupted before its neutral zero. This phenomena is callad current chopping
How inrush current limited in ups?
Omg girlz sign in the gorop
More the transformer impedance less the fault current... so is a high value of transformer impedance good for it?
It depends a lot on the application, i would go with low impedance transformers if am using the transformers for distribution as it will really increase the the maximum fault current. If am using the transformers as step up specially for generators or to charge capacitors, using a high impedance transformer is a good idea as it will decrease the inrush current of the system. you have to see your application and decide what fit that best. Mohammad Jaradat Power Generation Project Manager
