Jun. 26, 2019
Principle of isolating transformer
The principle of three-phase transformer and isolation transformer is the same as that of ordinary transformer. All by electromagnetic induction. Isolation transformer generally refers to 380V/380V, 400V/400V transformer. Because the secondary is not connected. There is no potential difference between any of the secondary lines and the ground. Safe to use. Often used for maintenance.
Isolation transformers are not all 1:1 transformers. The power source of the control transformer and tube equipment is also the isolation transformer. Power sources such as electronic tube amplifiers, electronic tube radios and oscilloscopes and lathe control transformers are isolating transformers. Such as for the safety maintenance of color TV commonly 1 than 1 isolation transformer. Isolation transformer is used more, in the air conditioning is also used.
Although there are isolation circuits between primary and secondary windings of transformers in general, the capacitance between the two windings will still cause electrostatic interference between the two sides of the circuit in the case of higher frequency. In order to avoid such interference, the primary and secondary windings of the isolating transformer are generally placed on different cores to reduce the capacitance between them. The primary and secondary windings are concentric, but electrostatic shielding is added between the windings to achieve high anti-interference.
Electrostatic shielding is to set a piece of copper sheet or non-magnetic conductive paper between the primary and secondary windings, which is called the shielding layer. Copper sheet or non-magnetic conductive paper is connected to the housing with wires. Sometimes for better shielding effect, a shielding shell is also covered throughout the transformer. The outgoing terminals of the windings are also shielded to prevent other external electromagnetic interference.
Only can make the original, so each winding between main remanent magnetism coupling, and meantime the equivalent distributed capacitance can be less than 0.01 pF, thereby significantly reducing the original, deputy winding capacitance current, effectively restrain all kinds of interference from the power supply as well as other circuit, tunnel transformer, three-phase transformer, isolation transformer, security transformer, special transformer, servo transformer.
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