The purpose of electrical isolation is to reduce the interference between two different circuits. For example, an actual circuit operating in a poor environment, easy to cause grounding and other faults. If electrical isolation is not adopted, it is directly connected to the power supply. Once the circuit is grounded, the whole power network may be affected by it and cannot work normally. When using electrical isolation, the circuit grounding will not affect the work of the power grid, and can also through the insulation monitoring device to detect the circuit of the insulation condition, once the circuit ground, can timely alarm, remind managers to repair or processed on time, avoid tripping protection device is a power failure occurs.
The isolating transformer shall be selected according to the voltage class of the power supply and the actual equipment. If the actual equipment is the same as the voltage class of the power supply, a transformer with a transformer ratio of 1 May be used. However, it must be noted that the isolation transformer cannot be used as an auto-transformer (since the primary and secondary windings of the auto-transformer have direct electrical connection, that is, they are not insulated, so they cannot be used as an electrical isolation). Special isolating transformer can be used in the case of high safety requirement.
General industrial control system includes both weak current control part and strong current control part. In order to maintain the control signal connection between the two, and to isolate the electrical connection, that is, the implementation of weak and strong electrical isolation, is to ensure the stability of the system, the equipment and the safety of operators is an important measure.
One of the purposes of electrical isolation is to isolate the interference source and the easily interfered part from the circuit, so as to achieve the purpose of isolating the field interference.