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Does varying the resistance in the secondary circuit cause a change in both the input and output currents to keep the power on both sides equal on a transformer?
Wiki User
∙ 17y ago
The simple answer is "NO". Whatever is tapped-off of the secondary, or otherwise modified, does in no way diminish the laws of transfer of power from one winding to the next, or available potential. Whatever is actually realized at the secondary will never be 100% of the input due to losses in transfer, such as heat losses. * I'm still not sure but having thought about it more I now think that if you increase the resistance in the secondary circuit and therefore decrease the secondary current, without changing either voltage, the power on the secondary would fall with the current. The primary power would also have to fall to remain equal to the secondary power (heat losses aside), and the primary current would also fall. Is this correct? Thanks Yes. Because a transformer is very efficient, power measured on each side is almost the same. P = VI = vi The voltage ratio V/v depends on the number of turns in the windings and is therefore constant. Decreasing resistance on the secondary side allows an increase in the current. Current on the primary also increases because power in is equal to power out.
Wiki User
∙ 17y ago
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What are the approximation of open circuit and short circuit test of transformer?
A short-circuit test is done to determine the power lost in the resistance of the primary and secondary windings of the transformer. It is done at full load current but with only enough voltage to give the required current with the secondary short circuited. An open-circuit test is done at full load voltage but no current is taken from the secondary, and this enables the power lost in the magnetic core of the transformer to be measured. As well a power, the tests also allow the inductances to be measured as well as the resistances, in order ot characterise the transformer fully.
What is the base voltage in a transformer circuit?
depends on the type of trans former.buck or boost.primary winding a secondary winding
What is no load current in transformer?
I'm not sure that it is correct to say a transformer limits current under no load (maybe it is, depending on your application).A step down transformer converts a high voltage at the primary to a lower voltage at the secondary. Under no load conditions, the secondary will be an open circuit. Since The primary current relative to the secondary current will be Np/Ns (the turns ratio, primary to secondary), and the primary voltage relative to the secondary is Ns/Np, the apparent resistance at the primary due to an open at the secondary will be (Np/Ns)^2*(open circuit). Since an open circuit is typically approximated as an infinite resistance, resistance is infinite. The turns ratio in this idealized example doesn't really matter, hence the transformer doesn't really matter (only the fact that a no load means an open secondary matters).AnswerUnder no-load conditions, the primary current is limited due to the voltage induced into the primary winding, which opposes the applied voltage (Lenz's Law).
Is the sum of the resistance in a parallel circuit always excessds the total resistance in a circuit?
Not sure what you mean. The equivalent (total) resistance in a parallel circuit is less than any individual resistance.
Why transformer action takes place in a DC circuit?
A: A transformer is a PASSIVE ac component applying dc to it the wires resistance would be the only limiter for current flow. Usually a common transformer will burn up fast or slowly depends on power applied
What is a curect transformer?
A 'current transformer' is a type of transformer which, together with a 'voltage transformer' (or 'potential transformer' in N America), is classified as being an 'instrument transformer'. It is used to reduce large currents to smaller currents which can be measured safely, and to isolate the primary circuit from the secondary circuit for the purposes of safety. Current transformers are also used to drive protective relays used in high-voltage protection systems.
How do you carry open circuit test on power transformer?
A Linear power transformer coil? use an Ohm meter and check the resistance of the coils. No resistance is an open circuit. Also check for a cross circuit from one side of the transformer to the other.
Why is the secondary of a transformer a short circuit?
If you are saying that the secondary (output) winding on a transformer seems to be a short circuit, it is very likely to be low resistance and may only be a few ohms if you measure the resistance with an ohmeter. The only way it would actually be a short circuit is if something has been inserted which has shorted the wires or it has overheated and burnt through. In which case there should be an acrid smell. Or if you can see the wires you would see they were burnt. A short in the circuit it is powering could cause the transformer to overheat, burn out and short.
What is principle of Current transformer?
why does have to short-circuit secondary wire of current transformer ?
What losses can be measured in a short circuit test of a transformer?
Winding copper losses of a transformer can be measured in a short circuit test of a transformer. Impedance voltage is given to the primary and the secondary is often shortcircuited. (some times the reverse is done of this). Full load currents are made to flow in both primary and secondary circuits. This current flow heats up the 2 windings of the transformer. Power consumed at this time gives the transformer copper losses.
What are the approximation of open circuit and short circuit test of transformer?
A short-circuit test is done to determine the power lost in the resistance of the primary and secondary windings of the transformer. It is done at full load current but with only enough voltage to give the required current with the secondary short circuited. An open-circuit test is done at full load voltage but no current is taken from the secondary, and this enables the power lost in the magnetic core of the transformer to be measured. As well a power, the tests also allow the inductances to be measured as well as the resistances, in order ot characterise the transformer fully.
What are uses of transformer's lamination?
Presumably, you are asking "What is the function of transformer laminations?", rather than their "uses".A transformer's magnetic circuit, or core, is made from thin sheets of silicon steel, each insulated from each other, and termed laminations.The alternating current flowing through a transformer's primary winding not only induces a voltage into the secondary windings, but into the core itself, resulting in circulating currents, called eddy currents, which result in energy losses. The very low cross-sectional area of each lamination acts to offer a high resistance to the flow of these eddy currents, thus minimising these currents, and the associated eddy-current losses.
What are the voaltg in isolation transformer?
The function of an isolation transformer is to electrically-isolate the secondary circuit from the primary circuit, without changing the voltage levels. So, its secondary voltage will be the same as the primary voltage.
Why don't AC input wires to a transformer just short circuit?
The resistance of the winding in the primary of a transformer constitutes a load. As long as there is resistance then there is no short circuit. A short circuit is considered no resistance which develops an instantaneous high current. That is why fuses and breakers are inserted into the circuit to open the high current flow under a short circuit condition.
Why does a phase in secondary side in distribution transformer give low voltage?
transformer is busted; if input voltage is normal you have short circuit or open circuit somewhere
When the transformer is connected to the power source the secondary current is 0 what is the possible fault in the transformer?
A secondary current of 0 would suggest to me that the secondary circuit is open. A normally operating circuit with zero current flow would be very unusual. No load in secondary circuit. No secondary current can also be attributed to the primary power source open or an open primary winding.
What does short circuit current available mean?
If you take a power source like a dc battery or AC transformer secondary winding and connect an ammeter directly across these power sources you can read the short circuit current available from that source. This gives a measure of internal resistance of the battery or the available wattage of the transformer.
