交流控制回路采用小型高阻抗中间继电器需注意的问题

工程中采用了小型中间继电器后，因为继电器较大的阻抗与电缆芯间的电容组成了容抗回路，致使在继电器回路断开后，仍在该继电器上残留了较大的电压导致继电器无法正常返回。将相应回路中电缆的备用芯两端接地，解决了继电器不能可靠返回的问题。在交流控制回路中应少采用小型高阻抗中间继电器，当采用小型高阻抗中间继电器时，应注意对继电器线圈电源回路的屏蔽或隔离。

Application of small interposing relay in AC control circuit

Small type interposing relay is now adopted in engineering projects,but causes the rem - nant high voltage caused by the capacitance - reactance circuit composed of the capacitance among cable cores and the large reactance of relay makes the relay unable to return to normal position after relay circuit is switched off.Grounding both ends of cable's spare cores can solve the pro - blem.The application of small type interposing relay with high reactance in AC control circuits should be avoided,otherwise the power circuit of relay coil should be shielded or isolated.