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What is the amount of primary current needed to supply the first secondary winding?
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When secondary coil is open there is no current in the primary coil WHY?
I am assuming the question is about the power / distribution transformer and not the current transformer. The primary current is a function of load connected on secondary. With the open secondary, there is no load, no current, it is open circuit. Hence no primary current. However there is always some small amount of no load current in the primary winding.
Why load is always connected to secondary of transformer?
b'coz at the secondary side large amount of current flow by recarding of active component or other ckt. which is connected to the secondary side so that ckt. is not damage or burned by flowing large amount .. load is connected at the secondary side .AnswerThe 'primary' winding of a transformer is, by definition, whichever winding is connected to the supply, whereas the 'secondary' winding is whichever winding is connected to the load. This does not mean that a load MUST be connected to a transformer, as it will work 'off load' -that is, with no load connected- without any harm.
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 )
Why transformer ratio is secondary winding voltage by primary winding voltage but not primary winding voltage by secondary winding voltage?
The transformer primary winding is connected to the alternating current supply. This causes a varying current in the primary winding, which creates a varying magnetic field in the transformer core. Because the primary voltage is alternating, the flux is also alternating - expanding and contracting, and changing polarity in time with the supply. This alternating core flux 'cuts' the secondary winding/s of the transformer, and induces a voltage in the secondary coil/s. As long as there is a magnetic field that is moving, and a conductor for it to move across, it will induce a voltage in the conductor. While the actual induced voltage depends on the amount of flux, the amount of conductor material and the rate of change of the flux, the actual voltage can be calculated from: Vsec = ((Vprim * Nsec) / Nprim) where V = voltage, N = number of turns of wire in the coil, prim = primary and sec = secondary. Transformers don't work on DC - they give a brief pulse out at switch-on and switch-off, because that's the only times the current is changing and the flux is moving. If you have to transform DC, you use a switching circuit that 'chops' the DC into a series of pulses that simulate AC as far as the 'moving flux' requirements of the transformer are concerned.
What value for a transformer determines the amount of voltage that is stepped up or down?
For an ideal transformer, the voltage ratio is exactly the same as its turns ratio. So if, for example, there are twice as many turns on the secondary winding as there are on the primary winding, then the secondary voltage will be twice that of the primary and the transformer will be a 'step up' type.
When secondary coil is open there is no current in the primary coil WHY?
I am assuming the question is about the power / distribution transformer and not the current transformer. The primary current is a function of load connected on secondary. With the open secondary, there is no load, no current, it is open circuit. Hence no primary current. However there is always some small amount of no load current in the primary winding.
How the input voltage is changed to an output voltage in a transformer?
Transformers work on the induction principal of the flux of the primary winding cutting the wires of the secondary winding. The amount of turns in the primary in relationship to the amount of turns in the secondary is the transformers winding ratio. This ratio is what governs the voltage value of the secondary winding.
Why load is always connected to secondary of transformer?
b'coz at the secondary side large amount of current flow by recarding of active component or other ckt. which is connected to the secondary side so that ckt. is not damage or burned by flowing large amount .. load is connected at the secondary side .AnswerThe 'primary' winding of a transformer is, by definition, whichever winding is connected to the supply, whereas the 'secondary' winding is whichever winding is connected to the load. This does not mean that a load MUST be connected to a transformer, as it will work 'off load' -that is, with no load connected- without any harm.
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 )
Why transformer ratio is secondary winding voltage by primary winding voltage but not primary winding voltage by secondary winding voltage?
The transformer primary winding is connected to the alternating current supply. This causes a varying current in the primary winding, which creates a varying magnetic field in the transformer core. Because the primary voltage is alternating, the flux is also alternating - expanding and contracting, and changing polarity in time with the supply. This alternating core flux 'cuts' the secondary winding/s of the transformer, and induces a voltage in the secondary coil/s. As long as there is a magnetic field that is moving, and a conductor for it to move across, it will induce a voltage in the conductor. While the actual induced voltage depends on the amount of flux, the amount of conductor material and the rate of change of the flux, the actual voltage can be calculated from: Vsec = ((Vprim * Nsec) / Nprim) where V = voltage, N = number of turns of wire in the coil, prim = primary and sec = secondary. Transformers don't work on DC - they give a brief pulse out at switch-on and switch-off, because that's the only times the current is changing and the flux is moving. If you have to transform DC, you use a switching circuit that 'chops' the DC into a series of pulses that simulate AC as far as the 'moving flux' requirements of the transformer are concerned.
What value for a transformer determines the amount of voltage that is stepped up or down?
For an ideal transformer, the voltage ratio is exactly the same as its turns ratio. So if, for example, there are twice as many turns on the secondary winding as there are on the primary winding, then the secondary voltage will be twice that of the primary and the transformer will be a 'step up' type.
How do you determine no load current and core loss of a single phase transformer?
It's easily done if you can measure the power drawn at the normal working voltage but with no load on the transformer (open-circuit secondary). All the power is core loss with the exception of a (very) small amount of resistive loss in the primary winding.
Can a flyback transformer be powered by nothing but a car battery and wires?
A transformer is an AC device in that it requires a changing current to be input in order to see an output. Attaching a 12V battery to the primary side of the transformer will generate a voltage on the secondary for a short amount of time. Once the primary current has risen to a stable level, there will be no output voltage on the secondary. There will also be voltages on the secondary and the primary when the battery is disconnected from the transformer. A flyback transformer relies on an AC current at the primary to generate a high voltage at the secondary output. Circuitry to make changes to the primary current will be needed in addition to the battery. Warning: removing the battery from the primary winding of the transformer is liable to generate a very high voltage across the primary coil as well as the secondary. In some cases, they can be lethal. Do not experiment with transformers unless you are properly qualified and supervised.
How step up transformer step up the input voltage?
It depends on the ratio of turns from primary to secondary.
What is a current transformer and how can a current transformer be used to extend the range of a wattmeter?
A current transformer (CT) works just like any other transformer. It is important to note it is not referenced to ground. It reflects current flow, not phase to ground voltage, so it attempts to hold current constant, not voltage. There is usually one primary "winding": one large cable through a donut CT, and multiple secondary windings. If a secondary winding is shorted (a wire placed across its terminals), the voltage built up in the secondary will be equivalent to V = I*Z, where I is the secondary current, and Z is the impedance of the secondary winding, usually specified as some flat value plus so many ohms per winding. If too big of an impedance is placed on the secondary, a voltage will build up to the point that the donut CT saturates, resulting in an output wave that has a large amount of harmonics. If the CT is open circuit\'d, voltage will build up until it is high enough to arc over (usually where it should have been shorted). CT\'s can be damaged by open circuiting them, so don\'t do it.
What does a flux density do in a single phase tramsformer?
Answer for USA, Canada and countries running a 60 Hz supply service.In an AC system the voltage alternates 120 times a second. This alternation causes the magnetic field that surrounds the wire in the primary coil to rise and collapse along with the voltage. This magnetic field is also known as magnetic flux. When the flux collapses and rises in the primary winding of the transformer this flux cuts the secondary coils and induces a current to flow in the secondary winding of the transformer. Depending on the amount of coil turns in the secondary, the AC voltage can be higher (step up) or lower (step down) than the primary voltage.
What is the impedance of a transformer?
Impedance (Z) voltage is the amount of voltage applied to the primary side to produce full load current in the secondary side. It is usually listed on the transformer nameplate, expressed as a percent, and measured by conducting a short circuit test.
