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What is the reason to use open circuit and short circuit methods to find Transformer losses?
Wiki User
∙ 9y ago
The transformer can be tested on open and short circuit to find the iron losses and copper losses separately, which uses a fraction of the power than having to run the transformer on full-load.
Wiki User
∙ 9y ago
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What is the use of a transformer with turns ratio 1?
isolation if you are in the usa and must service electronics the neutral is grounded the power supply is a voltage doubler one side is 170v+ to ground the other is 170v negative to ground so if you run the power thru the transformer first you stand a better chance of staying alive these transformers are quite often used to trigger scrs or triacs for the same reason
Why are transformer more efficient that rotating electric machines?
Because the electrical parts of a transformer do not move / rotate.
What is VA burden in electrical engineering?
The term 'burden' is used to describe the secondary load applied to an instrument transformer; the reason for this is so that it is not confused with the 'load' supplied by the high-voltage circuit to which the transformer's primary is connected. A burden is either a measuring instruments (ammeter,voltmeter, wattmeter, etc.) or protective relay, depending on the function of the instrument transformer. 'V.A' is the symbol for 'volt ampere', which defines the 'power' rating of the instrument transformer.
What does a step up transformer increase?
Power is normally transmitted at high voltage through step up/step down transformers to minimize the power losses in the transmission lines (this is one reason anyway). Since power loss is equivalent to the resistance of the conductor times the current squared, stepping up the voltage by a factor of two cuts the transmission losses by a factor of (2^2 = ) 4.
What are causes of voltage drop in transformer?
An ideal transformer (one with no losses, and not a bad approximation for the real thing) has an input power equal to its output power. In simple terms, since power is the product of voltage and current, then for a given value of power, as the voltage goes up, the corresponding current will go down.
Why is a motor rated in KW's and a transformer rated in KVA?
One reason is that the motor is expected to do work (watts) whereas a transformer only changes the voltage and (ideally) does no work. [Yes, losses do occur.]
In D.C supply the transformer is not connected why?
In a DC power supply a transformer is connected. The only time there would be no transformer used would be if the DC voltage wanted was 120 VDC. The transformer in the power supply is connected to 120 VAC on the primary side and the secondary side of the transformer is connected to either a half wave or a full wave diode bridge. The voltage out of the diode bridge will be the same output voltage potential as the transformer's secondary voltage but it will be a DC (Direct Current) potential.Reading the question in another way, transformers are not connected in a DC circuit. The reason being is that the transformer operates on a collapsing magnetic field. This field induces a voltage into the secondary side of the transformer. Since the DC circuit does not operate on the principle of a collapsing field except when the circuit is opened, the transformer would not operate as a transformer should..
What is the use of a transformer with turns ratio 1?
isolation if you are in the usa and must service electronics the neutral is grounded the power supply is a voltage doubler one side is 170v+ to ground the other is 170v negative to ground so if you run the power thru the transformer first you stand a better chance of staying alive these transformers are quite often used to trigger scrs or triacs for the same reason
Why are transformer more efficient that rotating electric machines?
Because the electrical parts of a transformer do not move / rotate.
What is the purpose of grounding the common leg of a 240 vac transformer in a residential air handler have seen some built with it and some without it?
It is the same reason as with the larger transformers, to provide a return circuit in case of a short circuit to ground. The large rush of current will take out the fuse or trip the circuit breaker. The second advantage is in trouble shooting, one lead of the tester is connected to the ground while you test for the voltage with the other. If the transformer was not grounded when trouble shooting , one lead of the tester would have to be on one leg of the transformer all during the test.
What is VA burden in electrical engineering?
The term 'burden' is used to describe the secondary load applied to an instrument transformer; the reason for this is so that it is not confused with the 'load' supplied by the high-voltage circuit to which the transformer's primary is connected. A burden is either a measuring instruments (ammeter,voltmeter, wattmeter, etc.) or protective relay, depending on the function of the instrument transformer. 'V.A' is the symbol for 'volt ampere', which defines the 'power' rating of the instrument transformer.
What does a step up transformer increase?
Power is normally transmitted at high voltage through step up/step down transformers to minimize the power losses in the transmission lines (this is one reason anyway). Since power loss is equivalent to the resistance of the conductor times the current squared, stepping up the voltage by a factor of two cuts the transmission losses by a factor of (2^2 = ) 4.
Why should the secondary of a voltage transformer not be short circuited?
A voltage transformer takes a primary voltage and steps it down to a smaller secondary voltage. This type of transformer will attempt to keep the secondary voltage at a specific ratio of the primary voltage. If you short it, massive current flow in the secondary is required to do this. For a similar reason a CT should never be open circuited - because it attempts to push a specific ratio of primary current through the secondary. If you open circuit the secondary, it takes a massive voltage on the secondary to accomplish this.
What are causes of voltage drop in transformer?
An ideal transformer (one with no losses, and not a bad approximation for the real thing) has an input power equal to its output power. In simple terms, since power is the product of voltage and current, then for a given value of power, as the voltage goes up, the corresponding current will go down.
Why should the secondary of a power transformer not to be left on an open circuit?
In general there is no reason why it should not be, though there may be special situations. Perhaps there is confusion with CURRENT transformers which must not be left open circuit because of the high voltages which they will produce. it may trip the CB. although there is no faults but a high current called Inrush current is flow when the the power transfomer energized while its secondry circuit is open
The leakage flux of transformer depends on?
Actually it depends on the air gap between the core and the windings of the transformer. This is the reason why stepped core is used in medium and large transformers as it decreases the air gap between the windings and the core of the transformer.
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.
