Galvanic isolation

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Galvanic Isolation is the principle of isolating the functional parts of the electrical system to prevent current flow; no direct conduction path is allowed. Energy or information can still be exchanged between parts in other ways, such as capacitance, induction or electromagnetic waves, or with optics, acoustics or mechanics.

Galvanic isolation is used where two or more electrical circuits must communicate, but their reasons may be at different potential. This is an effective method for breaking ground loops by preventing unwanted currents from flowing between two grounded conductor sharing units. Galvanic isolation is also used for safety, preventing unintentional flows reaching the ground through a person's body.

Video Galvanic isolation

Metode

Transformer

Transformer paired with magnetic flux. The primary and secondary windings of the transformer are not connected to each other (autotransformer has a conductive relationship between the windings so as not to provide insulation). The voltage difference that can be safely applied between winding without risk of damage (isolation voltage) is determined in kilovolts by industry standards. The same is true for transductors. While the transformer is usually used to change the voltage, an isolation transformer with a 1: 1 ratio is used in security applications.

If two electronic systems have in common, they are not isolated galvanically. The common ground may be abnormal and intentionally has a connection to the functional pole, but may become connected. For this reason isolation transformers do not provide GND/poles of the earth .

Opto-isolator

Opto-isolators transmit information with light waves. The sender (light source) and receiver (photosensitive device) are not electrically connected; usually they are held in place in a transparent plastic matrix, isolation.

Capacitor

The capacitor allows alternating current (AC) to flow, but blocking direct current; they combine the ac signals between circuits at different direct voltages. Depending on the conditions, the capacitor may fail and become "short-circuited", terminate its electrical isolation function, which creates a risk to the "connected circuit" and, possibly, the human hazard. To answer this question, there is a special rating for capacitors used for security isolation, such as "Class Y".

Hall Effects

Hall effect sensor enables the inductor to transfer information across magnetic slits. Unlike opto-isolators they do not contain light sources with limited life, and in contrast to transformer-based approaches they do not require DC balancing.

Magnetoresistance

Magnetocouplers use giant magnetoresistance (GMR) to couple from AC to DC.

Maps Galvanic isolation

Apps

Optocouplers are used in systems to separate the function blocks from others connected to the power grid or other high voltage, for the safety and protection of equipment. For example, a power semiconductor connected to an utility voltage can be diverted by an optocoupler that is driven from a low-voltage circuit, which need not be isolated for higher line voltages.

Transformer allows device output to "float" relative to the ground to avoid potential ground loops. The power isolation transformer enhances the security of the device, so that someone touching the active part of the circuit will have no current flowing through them to the earth. Power sockets intended for the supply of electric razors can use an isolation transformer to prevent electric shock if the razor should fall into the water.

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References

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See also

• Opto-isolator

Source of the article : Wikipedia