Dry-type isolation transformer

Dry-type isolation transformers are widely used in Circuits with AC 50Hz to 60Hz and voltages below 660V, the product’s various inputs, output voltage levels, connection groups, the number and position of adjustment taps (generally ±5%), and winding capacity The distribution of the secondary single-phase winding, the use of the rectifier Circuit, whether it is required to have a casing, etc., can be carefully designed and manufactured according to the requirements of users.


  • 1. Working principle of dry-type isolation transformer
  • 2. The role of dry isolation transformer

  • 3. Application of dry-type isolation transformer

1. Working principle of dry-type isolation transformer

The principles of dry-type isolation transformers and ordinary transformers are actually the same, using the principle of electromagnetic induction. Isolation transformer generally refers to a 1:1 transformer. Since the secondary is not connected to the ground, there is no potential difference between the wires in the secondary and the ground, which makes the instrument safer and is often used to repair the power supply. Isolation transformers are not all 1:1 transformers. Control transformers and Electronic tube equipment power supplies also belong to isolation transformers, which are also widely used in areas such as air conditioning and maintenance.

Dry-type isolation transformer

2. The role of dry isolation transformer

The main function of the dry-type isolation transformer is to isolate the electrical equipment from the power grid, and is used in safety occasions or occasions with anti-interference requirements. There is no direct electrical connection between the electrical equipment and the power supply. There is no direct electrical connection between the primary and secondary coils of the isolation transformer, and the electric-magnetic-electrical conversion is carried out through the magnetic field. In this way, the Three-Phase winding in the primary side can be connected to the primary side by the delta connection method. The odd harmonics in the primary side will form a circulating current in the primary side winding and will not flow to the secondary side, so the harmful harmonics in the power grid will be reduced.

Dry-type isolation transformer

3. Application of dry-type isolation transformer

1. Connect the isolation transformer (delta/star) to the power input

1. If the third harmonic and interference signal of the power grid are more serious, the use of △/Yo isolation transformer can remove the third harmonic and reduce the interference signal.

2. A △/Yo isolation transformer can be used to generate a new neutral line, so that the equipment has nothing to do with the neutral line of the power grid and avoid the abnormal operation of the equipment due to the bad neutral line of the power grid.

3. The current waveform distortion (such as the third harmonic) caused by the nonlinear load can be isolated without polluting the power grid.

2. Connect the isolation transformer (star/delta) at the output end of the power supply

1. Prevent the current distortion of the non-linear load from affecting the normal operation of the stabilized power supply and returning to the grid, playing the role of purifying the grid;

2. The distortion of the nonlinear load current affects the accuracy of sampling. You can sample at the input of the Yo/△ isolation transformer to obtain a control signal that can reflect the actual situation, so that the regulated power supply can be controlled normally;

3. If the load is unbalanced, the use of Yo/△ will not affect the normal operation of the regulated power supply.

Dry-type isolation transformer


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