The principle of isolation transformer

The principle of an isolation transformer is the same as that of an ordinary transformer. They all utilize the principle of electromagnetic induction. Isolation transformers generally refer to 1:1 transformers. Due to the secondary not being connected to the ground. There is no potential difference between any secondary wire and the ground. Safe to use. Commonly used as a maintenance power supply.
Isolation transformers are not all 1:1 transformers. The power supply for control transformers and electronic tube equipment is also an isolation transformer. Power sources such as electronic tube amplifiers, electronic tube radios, oscilloscopes, and lathe control transformers are all isolation transformers. For safe maintenance of color televisions, a 1:1 isolation transformer is commonly used. Isolation transformers are commonly used and are also used in air conditioning.
Although there is also an isolation circuit between the primary and secondary windings of a general transformer, the capacitance between the two windings can still cause static interference between the circuits on both sides at higher frequencies. To avoid such interference, the primary and secondary windings of the isolation transformer are generally placed on different cores to reduce the capacitance between the two; There are also cases where the primary and secondary windings are placed concentric, but electrostatic shielding is added between the windings to achieve high anti-interference performance.
Electrostatic shielding refers to the installation of an unclosed copper sheet or non magnetic conductive paper between the primary and secondary windings, known as a shielding layer. Copper sheets or non magnetic conductive paper are connected to the casing with wires. Sometimes, in order to achieve better shielding effect, a shielding shell is also covered throughout the entire transformer. Shield the outgoing terminals of the winding to prevent other external electromagnetic interference. This can make the coupling between the primary and secondary windings mainly consist of residual magnetism, and the equivalent distributed capacitance between them can be less than 0.01pF, greatly reducing the capacitive current between the primary and secondary windings and effectively suppressing various interferences from the power supply and other circuits.