What kind of transformer is a current transformer, and what is the difference between a current tran

Clause. 1. The current transformer is a special kind of transformer, and the relationship between the primary and secondary sides is exactly the same as that of the transformer.

Clause. Second, the so-called secondary side to the primary side degaussing the saying exists in transformers and transformers, and a small part of the primary side is used for excitation. During normal operation, the excitation current is independent of the load. As the secondary current increases, the primary side also increases proportionally.

Clause. Third, the formula of voltage ratio is established. If the excitation current is considered, the current ratio does not hold. However, when the secondary current is large, the current ratio is approximately true because the excitation current is small.

Clause. Fourth, the reason for the low secondary voltage of the current transformer is that the primary voltage is very low (generally we only pay attention to the primary current), in contrast, the secondary voltage is still higher than the primary side.

Clause. 5. The secondary voltage of the step-up transformer is high because the primary voltage is also high. Compared with the current transformer of 500A 5A and the step-up transformer of 5V 500V, the conversion ratio is the same, both are 100.

However, the input voltage of the current transformer is in the microvolt range (the voltage drop of the primary resistor is not considered, only the excitation voltage drop is considered), while the input voltage of the step-up transformer is 5V.

Current transformers.

Voltage transformers all belong to transformers, but their uses are different, and the principle is the same.

The main function of the current transformer is to ensure the safe and economical operation of the power system, and the operation of the power equipment must be monitored and measured. However, the general measurement and protection device cannot be directly connected to the primary high-voltage equipment, but needs to convert the large current of the primary system into a small current proportionally, and supply the measuring instrument and protection device for use.

Alternating currents are being measured.

When the current is large, in order to facilitate the measurement of the secondary instrument, it needs to be converted into a relatively uniform current (China stipulates that the secondary rating of the current transformer is 5A or 1A), and the voltage on the line is relatively high, such as direct measurement is very dangerous. The current transformer plays the role of converter and galvanic isolation. It is a measuring instrument and relay protection in the power system.

The current transformer converts the high current into a low current in proportion, the current transformer is connected to the primary system on the primary side, and the measuring instrument and relay protection are connected on the secondary side.

The transformer mainly provides the voltage level.

Transformed devices.

The transformer is a transformer, the transformer is a transformer, and the question you are asking is problematic in itself, so you must clarify the definition.

The principle of the current transformer is based on the principle of electromagnetic induction. A current transformer is made up of a closed core and windings. Its primary winding turns are very small, and the string is in the line of the current that needs to be measured, so it often has all the current of the line flowing through, and the number of secondary winding turns is relatively large, which is connected in series in the measuring instrument and the protection circuit, and when the current transformer is working, its secondary circuit is always closed, so the impedance of the series coil of the measuring instrument and the protection loop is very small, and the working state of the current transformer is close to a short circuit.

The transformer is a device that uses the principle of electromagnetic induction to change the AC voltage, and the main components are the primary coil, the secondary coil and the iron core (magnetic core), and the main functions are: voltage conversion, current conversion, impedance conversion, isolation, voltage stabilization (magnetic saturation transformer), etc. According to the use, it can be divided into:

Distribution transformers, power transformers, fully sealed transformers, combined transformers, dry-type transformers, oil-immersed transformers, single-phase transformers, electric furnace transformers, rectifier transformers, etc.

Step-up transformers that focus on current parameters

Hello:— 1. The transformer hasThree working states, i.e.: ,Change the voltageChange the currentChange the impedance

2. The first working state: the transformer canChange the voltage, that is, what is commonly calledTransformers；The second working state: the transformer canChange the current, i.e.: ,converters, that isCurrent transformers. ；The third working state:

Transformers canChange the impedance, i.e.: ,Line-to-line transformersOutput transformerMatching transformerWait.

Current transformers. , that isconverters, is working inShort circuitstateSpecial transformers

The working principle of transformer and current transformer is the same, the difference is that the structure and use are noisy, the transformer is used for the rise and fall of the pulse voltage change, and the current transformer is used for metering. The main differences are as follows:

The current transformer is strictly forbidden to open the secondary side, because this liquid sock will cause the excitation current of the primary current is all the core, so that it will be saturated and induce high voltage on the secondary side, and the insulation breakdown accident will occur, while the transformer has no such limitation.

The impedance of the load connected to the secondary side of the current transformer is very small, which is approximate to short circuit, and the secondary side of the transformer is not allowed to short circuit.

The design value of the magnetic flux density of the core of the current transformer is low, only; The magnetic flux density of the transformer core, cold-rolled silicon steel sheet, hot-rolled silicon steel sheet.

The secondary current of the current transformer varies with the magnitude of the primary current, while the transformer is reversed, and the magnitude of the primary current is determined by the magnitude of the secondary (i.e. load) current.

The difference between the principle of a current transformer and a transformer:

Current transformer and transformer principle.

Pretty much the same, in terms of structure, they are all two windings: one has more turns and a thin wire diameter, and the other has fewer turns and a thick wire diameter.

If the winding with a large number of turns and a thin wire diameter is connected in parallel with the measured circuit as a primary winding, and the winding with a small number of turns and a thick wire diameter is connected to a measuring instrument (voltmeter), then the transformer is a voltage transformer.

The voltage transformer is actually a step-down transformer that works in the no-load state (because the voltmeter is a high-resistance meter and the current is very small, it is no-load. And because the number of turns of the primary winding is large and the number of turns of the secondary winding is small, it is a step-down).

If the winding with a small number of turns and a thick wire diameter is connected in series with the measured circuit as a primary winding, and the winding with a large number of turns and a thin wire diameter is connected to a measuring instrument (ammeter), then the transformer is a current transformer. The current transformer is actually a step-up transformer that works in a short-circuit state (because the ammeter is a low-resistance meter and the current is very large, it is equivalent to a short circuit. And because the number of turns of the primary winding is small and the number of turns of the secondary winding is large, it is a boost, and the reason why the secondary winding voltage of the actual current transformer is not boosted is because it works in a short-circuit state).

When the current transformer is working, the secondary winding must not be open.

Otherwise, it will induce high voltage and endanger the safety of equipment or personnel, and due to the loss of the demagnetizing magnetic potential of the secondary winding, the core will be seriously saturated and the accuracy of the measurement will be lost. The current transformer (CT) is not allowed to open the circuit during operation.