What do the turns ratio of a transformer affect

The table below shows each test with a description, the related specifications and a summary of the benefit provided by that test. The ratio measured with this test therefore includes the losses normally found in the transformer, which will result in a ratio greater than that of the physical turns but reflects the real voltage ratio expected by the designer.

Reduces the effect on measured turns ratio of transformer losses, giving a closer approximation to the physical turns ratio. This is of particular benefit where actual turns are of interest but the transformer has a large proportion of leakage inductance which may have a significant effect on the voltage ratio.

This simplifies test limit entry when the transformer specification has been derived from voltmeter measurements. By controlling an external power source with the Voltech AC Interface Fixture, the VOCX test provides fully automatic testing of high-power transformers at their specified working voltage. While turns ratio may be a well known and very fundamental function in a transformer, it can be seen that testing this function effectively requires the consideration of many issues.

By providing a flexible range of turns ratio test options, the Voltech AT series testers provide designers and manufacturers alike with the opportunity to select the most appropriate tests for any transformer design and therefore optimise the quality and efficiency of their test process. Should you have questions on any of the other test functions available for the Voltech AT series transformer testers, please do not hesitate to contact us.

Submitting email, please wait.. Email and Questions are required fields. Voltage and Current Turns Ratio Definitions 3, Factors Affecting Turns Ratio Measurements With a theoretical, "ideal" transformer, the ratio of the physical turns on any winding could be established simply by measuring the RMS output voltage on one winding, while applying a known RMS input voltage of an appropriate frequency to another winding. L1, L2 and L3 represent the primary and secondary leakage inductance caused by incomplete magnetic coupling between the windings.

R1, R2 and R3 represent the resistance or copper loss of the primary and secondary windings. C1, C2, and C3 represent the interwinding capacitance.

Lp represents the magnetizing inductance core loss. Rp represents the core loss of which three areas contribute, eddy current loss increases with frequency , hysteresis loss increases with flux density and residual loss partially due to resonance. By controlling an external power source with the Voltech AC Interface Fixture, the VOCX test provides fully automatic testing of high-power transformers at their specified working voltage 6, Conclusion On Testing for Turns Ratio While turns ratio may be a well known and very fundamental function in a transformer, it can be seen that testing this function effectively requires the consideration of many issues.

Three passes yield a CT. One reason to do this is that a higher ratio CT generally has better performance than a low ratio CT. The accuracy and burden characteristics of a CT are not changed by using multiple primary turns. However, the window must be large enough to accommodate the additional turns of heavy gauge primary wire. Smaller ratio changes can be made by using additive or subtractive turns on the secondary.

On a CT with one primary turn and a 5 amp secondary, each secondary turn modifies the ratio by 5 amps. One turn additive on a CT becomes a CT. One turn subtractive becomes a CT. An additive turn is wound by running the X1 lead through the window from the H2 to the H1 direction from the side opposite the polarity mark. A subtractive turn runs the opposite direction from the side with the polarity mark. Adjusting both primary and secondary turns provides additional ratios for a specific current transformer.

When the primary winding is energized with an alternating current AC , alternating magnetic lines of force, called "flux," circulates through the core, establishing a magnetic field. With a second winding wrapped around the same core , a voltage is induced by the magnetic field. This winding is called the secondary winding.

The amount of voltage induced in each turn of the secondary winding will be the same as the voltage across each turn of the primary winding; this is referred to as the transformer turns ratio. If the secondary winding has fewer turns than the primary, a lower voltage will be induced in the secondary. This type of transformer is called a step-down transformer.

A secondary coil with twice as many turns as the primary will be cut twice as many times by the magnetic flux , and twice the applied primary voltage will be induced in the secondary. This transformer is known as a step-up transformer. Note: The primary is always connected to the source of power , and the secondary is always connected to the load.

Either the high- or low-voltage winding can be the primary or the secondary. The total induced voltage in each winding is proportional to the number of turns in that winding and the current is inversely proportional to both voltage and number of turns. E1 is the primary voltage and I1 the primary current, E2 the secondary voltage and I2 the secondary current, N1 the primary turns and N2 the secondary turns. If voltage is stepped up, the current must be stepped down and vice versa.

The number of turns remains constant unless there is a tap changer. If the primary voltage of a transformer is volts V , the primary winding has turns, and the secondary winding has turns, what will the secondary voltage be?

Since there is a ratio of 1 to 4 between the turns in the primary and secondary circuits, there must be a ratio of 1 to 4 between the primary and secondary voltage and a ratio of 4 to 1 between the primary and secondary current.

As voltage is stepped up, the current is stepped down, keeping volts multiplied by amps constant. This is referred to as " volt amps. Calculate the ratio of each three-phase winding based on the line to neutral voltage of the wye winding.

Divide the line-to-line winding voltage by 1.