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When a transformer steps down a power source what will remain the same the frequency the voltage or the current or none of these?
Wiki User
∙ 13y ago
The frequency remains the same as one cycle in the primary corresponds to one cycle in the secondary.
The stepdown voltage on the secondary as a ratio of the voltage on the primary will be the same as the ratio of turns in the primary to turns in the secondary.
The current in the secondary depends on two things: the current that the load is taking at the lower voltage of the secondary and the relative thickness of the wire in the secondary to the thickness of the wire in the primary.
ANSWER: A transformer does not step up/down a power source ever it does however step up/down the voltage related to the primary. A typical transformer will always have an efficiency loss. The frequency on the output will remain the same as the input. It is not true that the big wires will give you more current that would be true only if the iron core is increased accordingly. otherwise saturation will occur
Wiki User
∙ 13y ago
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What happems when frequency is changed and voltage and current remain unchanged?
In magnetic circuits, such as occur in transformers and motors, the flux density is inversely proportional to the frequency, so a drop in frequency could cause overheating through excessive flux density.
Why transformer not obey ohms law?
A: Ohms law apply to any and to all components if there is current flowing.AnswerFor Ohm's Law to apply, the ratio of voltage to current must remain constant for variations in voltage. This is only true for a limited range of conductors and devices which are termed 'linear' or 'ohmic'. If the ratio of voltage to current changes for variations in voltage, then the conductor or device is 'non-linear' or 'non-ohmic', and Ohm's Law does NOT apply. An example of a non-ohmic conductor is tungsten (e.g. a lamp filament) and an example of a non-linear device is a diode -there are many more.As to whether a transformer obeys Ohm's Law, the answer is not straightforward. When the transformer is not supplying a load, the primary current is determined by the voltage and impedance of the primary windings and, say, doubling the voltage will double the primary current -so you could say that it is obeying Ohm's Law. However, when the transformer is supplying load, the primary current is determined by the secondary current and not just by variations in the supply voltage, so is clearly not obeying Ohm's Law.
If the resistance increases what will happen to voltage and current?
If you have a simple circuit. For eg: One voltage source and one resistor, then the voltage of the circuit will always remain the same, the current however will decrease following Ohms' Law V=I*R. If we have a current source instead of a voltage source, we are forcing the current to be a certain value so if we increase the resistor value the current will remain the same but the voltage will increase.
Why does the current rise when the voltage drops?
It is not generally true that current increases when the voltage decreases. Ohms law for a simple resistor says that current is proportional to voltage. However an electric motor supplying a constant mechanical load power will readjust to a lower supply voltage by drawing more current, although if the voltage is progressively reduced the motor would stall. Switch-mode power supplies also tend to draw a constant power from the supply when the input voltage changes.
What is the effect on the current in a wire if both the voltage across it and it's resistance are doubled?
By Ohm's Law, current is voltage divided by resistance, so if you double both the voltage and the resistance, the current would remain the same.
On a step up transformer if the input is 200 Hz will the out put also be 200 Hz?
Yes. Transformers affect the current and voltage of the applied power. The frequency will remain the same.
What happens to the current as the voltage is increased by the step up transformer?
Compare a transformer to a balancing act. Both side need to remain equal.The primary side of the transformer is the supply side and the load is connected to the secondary side of the transformer.The load governs the current of the secondary side of the transformer and the voltage of the secondary side must match the voltage that the load required to operate.The ratio of the transformer will determine what the voltage of the secondary side is as compared to the voltage that has to be applied to the primary.The current of a step up transformer will be higher on the primary side that that of the secondary.Apply voltage and current to this concept and you will see that the transformer will remain balanced.The size of the transformer is always calculated from the secondary side of the transformer and the value is written in VA or KVA where V = voltage and A = amperage. Power factor is also taken into consideration when calculating the size of the transformer to be used.
What happems when frequency is changed and voltage and current remain unchanged?
In magnetic circuits, such as occur in transformers and motors, the flux density is inversely proportional to the frequency, so a drop in frequency could cause overheating through excessive flux density.
Why transformer not obey ohms law?
A: Ohms law apply to any and to all components if there is current flowing.AnswerFor Ohm's Law to apply, the ratio of voltage to current must remain constant for variations in voltage. This is only true for a limited range of conductors and devices which are termed 'linear' or 'ohmic'. If the ratio of voltage to current changes for variations in voltage, then the conductor or device is 'non-linear' or 'non-ohmic', and Ohm's Law does NOT apply. An example of a non-ohmic conductor is tungsten (e.g. a lamp filament) and an example of a non-linear device is a diode -there are many more.As to whether a transformer obeys Ohm's Law, the answer is not straightforward. When the transformer is not supplying a load, the primary current is determined by the voltage and impedance of the primary windings and, say, doubling the voltage will double the primary current -so you could say that it is obeying Ohm's Law. However, when the transformer is supplying load, the primary current is determined by the secondary current and not just by variations in the supply voltage, so is clearly not obeying Ohm's Law.
How can in series connection current remain constant while the voltage change while by ohm's law voltage is directly proportional to current?
If the voltage between the ends of a series circuit changes, the current in thecircuit definitely does not remain constant. The current does change by the samefactor as the voltage.The current at every point in the series circuit is the same current.
How does the number of cells affect the current in a circuit?
More cells = more available power. Power = voltage * current. The orientation of the cells determines whether this power is delivered as more voltage, or more current. If the cells are in series, the voltage will increase proportionately and the available current will remain unchanged; if the cells are in parallel, the current will increase proportionately and the voltage will remain unchanged.
If the resistance increases what will happen to voltage and current?
If you have a simple circuit. For eg: One voltage source and one resistor, then the voltage of the circuit will always remain the same, the current however will decrease following Ohms' Law V=I*R. If we have a current source instead of a voltage source, we are forcing the current to be a certain value so if we increase the resistor value the current will remain the same but the voltage will increase.
What happens to the voltage if the current increases?
Yes, if the resistance remains constant. Power is voltage times current, and current is voltage divided by resistance, so power is voltage squared divided by resistance. In essence, the power increases as the square of the voltage.
Why does the current rise when the voltage drops?
It is not generally true that current increases when the voltage decreases. Ohms law for a simple resistor says that current is proportional to voltage. However an electric motor supplying a constant mechanical load power will readjust to a lower supply voltage by drawing more current, although if the voltage is progressively reduced the motor would stall. Switch-mode power supplies also tend to draw a constant power from the supply when the input voltage changes.
What will be input and output current of 10 KVA 3 phase UPS?
It will depend on input & output voltage, if voltage is same current will remain same
What is the effect on the current in a wire if both the voltage across it and it's resistance are doubled?
By Ohm's Law, current is voltage divided by resistance, so if you double both the voltage and the resistance, the current would remain the same.
What is percentage impedance?
In electrical engineering, the percentage impedance of a transformer is the voltage drop on a full load, which is expressed as a percentage of the specified rated voltage. It's measured by conducting a short circuit test.
