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Does a transformer draw a lot of current when first connected to a source?
Wiki User
∙ 14y ago
Yes it does as it is an Inductor and an Inductor needs to build up a magnetic field. It is called INRUSH current.
Wiki User
∙ 14y ago
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What will happen to the transformer if DC voltage is applied to the primary winding?
DC current will not pass through a transformer, in the sense that a DC current on the primary will not produce a DC output from the secondary. A constant DC current will not produce any output from the secondary but there may be transient effects as the DC current is connected or disconnected (in which case, it's really an AC current, isn't it?) More about this below because I don't think that's really the question. If you pass DC current through either winding of a transformer, two things will happen. First, you will heat up the transformer and, if you have enough DC current, you will burn it out. Second, you will induce a magnetic field in the core. The more current, the closer the core gets to "saturation" or the maximum field it can support. This is important if there is both DC and AC current present because the more DC field in the core, the less core capacity is available to "transform" AC current. As the core operates closer to saturation, the AC waveform will be distorted and some of the AC power will be lost to heating the transformer. For example, if the primary of a transformer is connected to an AC source, and a DC source is connected to the secondary, then the primary current drawn by the transformer will increase, possibly enough to destroy the transformer. There are special transformers, called magnetic amplifiers, which take advantage of this effect to use a DC current to modulate an AC current. There are transient effects of DC currents in a transformer winding. As the DC current magnetizes the core, energy is stored. When the DC current is disconnected, this stored energy wants to leave the core. It can do this by inducing a voltage in either of the windings. If both windings are open circuit, this voltage can be very high. So you may see a spark jump when the DC voltage is disconnected. In a large transformer, this discharge may break down the transformer insulation and damage it. Some switching power supplies take advantage of this effect in which case the transformer is wound slightly differently and called a "coupled inductor."
What is the role of magnetizing current in transformer?
connect 3 - phase supply to transformer primary winding.....keep transformer secondary winding open..... apply 3-phase voltage i.e.400v ac, and measure the amount of current flowing in each phase of the transformer primary winding...this current is the transformer magnetising current..... we can keep multimeters in series with the source....so we can measure directly the current readings.....(keep multimeters in current mode, and generally magnetising current will come in terms of milli amps for 400 v )
How transformer get burn?
Current overload from whatever circuit draws current from the transformer? Proper fusing of its supply might protect a transformer from this cause. Or it could have developed a shorted turn fault because the insulation on a winding got old and perished? Or maybe the transformer got damaged if the appliance it is mounted in was dropped?
What is the load of a step down transformer for 40HP?
Hi, First understand one thing seriously!! The transformer only can be rated in KVA. Bcoz, its power factor not depends on the load connected.
Will a bell ringing transformer operate on direct current?
No. Transformers always operate only on alternating current. They will burn up on direct current. That is, if the fuse does not blow first.
How does current transformer works in a substation?
A current transformer works on the same principle as that of a simple transformer however it steps down the high current into a low level so that it can be measured using an ammeter of a suitable range. In some current transformers extra cores are provided. This is done in order to prevent the faulty currents i.e. the over currents, earth faults, differential protections. The extra cores of a C.T. gets saturated as soon as the faulty currents starts flowing and thereby does not harm the main core of the transformer and the ammeter connected. The C.T. is always connected in the line carrying current. It first steps down the current to a measureable form and further gives this current to the ammeter.
What will happen to the transformer if DC voltage is applied to the primary winding?
DC current will not pass through a transformer, in the sense that a DC current on the primary will not produce a DC output from the secondary. A constant DC current will not produce any output from the secondary but there may be transient effects as the DC current is connected or disconnected (in which case, it's really an AC current, isn't it?) More about this below because I don't think that's really the question. If you pass DC current through either winding of a transformer, two things will happen. First, you will heat up the transformer and, if you have enough DC current, you will burn it out. Second, you will induce a magnetic field in the core. The more current, the closer the core gets to "saturation" or the maximum field it can support. This is important if there is both DC and AC current present because the more DC field in the core, the less core capacity is available to "transform" AC current. As the core operates closer to saturation, the AC waveform will be distorted and some of the AC power will be lost to heating the transformer. For example, if the primary of a transformer is connected to an AC source, and a DC source is connected to the secondary, then the primary current drawn by the transformer will increase, possibly enough to destroy the transformer. There are special transformers, called magnetic amplifiers, which take advantage of this effect to use a DC current to modulate an AC current. There are transient effects of DC currents in a transformer winding. As the DC current magnetizes the core, energy is stored. When the DC current is disconnected, this stored energy wants to leave the core. It can do this by inducing a voltage in either of the windings. If both windings are open circuit, this voltage can be very high. So you may see a spark jump when the DC voltage is disconnected. In a large transformer, this discharge may break down the transformer insulation and damage it. Some switching power supplies take advantage of this effect in which case the transformer is wound slightly differently and called a "coupled inductor."
What is the role of magnetizing current in transformer?
connect 3 - phase supply to transformer primary winding.....keep transformer secondary winding open..... apply 3-phase voltage i.e.400v ac, and measure the amount of current flowing in each phase of the transformer primary winding...this current is the transformer magnetising current..... we can keep multimeters in series with the source....so we can measure directly the current readings.....(keep multimeters in current mode, and generally magnetising current will come in terms of milli amps for 400 v )
What happens to the current in a secondary that has twice as many loops as the primary?
The current in the secondary winding of a transformer is not determined by the current flowing in the primary winding; rather, it is the other way around.The current flowing through the secondary winding of a transformer is determined by the load to which it is connected. The primary current can then be determined from the turns ratio.
How transformer get burn?
Current overload from whatever circuit draws current from the transformer? Proper fusing of its supply might protect a transformer from this cause. Or it could have developed a shorted turn fault because the insulation on a winding got old and perished? Or maybe the transformer got damaged if the appliance it is mounted in was dropped?
If DC is applied to the primary of a transformer is there any current in the secondary and if there is then whether ac or DC?
first, understand that a transformer is an AC DEVICE. it wont work on dc...
What is the load of a step down transformer for 40HP?
Hi, First understand one thing seriously!! The transformer only can be rated in KVA. Bcoz, its power factor not depends on the load connected.
Will a bell ringing transformer operate on direct current?
No. Transformers always operate only on alternating current. They will burn up on direct current. That is, if the fuse does not blow first.
What is the definition for Input high current and input low current?
Let me first correct the question "current" here should be "tension" current is the speed of the electrons moving through the conductor and tension is the EMF that make the electrons move you cannot input current. the current is the demand of the circuit, depending on the resistance and the EMF(Electro Motoric Force) in other words, the Volts that is applied or input to the circuit.Answer:Any transformer can be used as a up step(inverting) or down step(converting) transformer, for instance 220V - 6V will be a converting and the 220V side will be your primary or high tension input and if you turn it around the 6V side will be your primary or low tension input.
How can you get a 240V single-phase power from a 120V 3-phase service?
First of all there is no common three phase 120 volt service. There is in North America a three wire 120/240 volt single phase service. That being said, if you want to change a 120 volt source to 240 volts it must be done with a transformer. Its classification is a step up transformer. The primary side of the transformer H1 - H2 will be connected to the 120 volts. The secondary side of the transformer X1 - X2 will be connected to the 240 volt load. The transformer is sized by the current required by the 240 volt load.
What happens to a transformer when it is first connected to a power line Can anything be done to mitigate this problem?
If rating is correct, terminal connections are correct, if safety devices are in place, if device is a standard with necessary requrement, it should not be problem to connect a transformer first time.
How should I calculate this. A single phase transformer is rated at 99kVA The primary voltage is 6.6kV and the secondary voltage is 220V Assume no losses and calculate The full load primary current?
First find the ratio of the transformer. 6600/220 volts. Second find the secondary current, I = W/E, 99000/220. Third divide the secondary current by the transformer ratio. The answer will be the primary current. To check your answer (W (or VA) = V x A) multiply the primary current times the primary voltage and the secondary current times the secondary voltage and they should both equal the transformer's kVA.
