Trong thiết bị điện tăng cường an toàn, chẳng hạn như động cơ chống cháy nổ, máy biến áp, dây điện từ, và chấn lưu cho đèn huỳnh quang, một phần bao gồm cuộn dây bên trong. Yêu cầu đối với các cuộn dây này, cả về cơ khí và điện, cao hơn so với cuộn dây tiêu chuẩn.
Nói chung là, dây cách điện dùng để quấn các cuộn dây này phải được cách điện kép, and the coil’s rated diameter must not be less than 0.25mm.
For the enameled wire used in winding these coils, it is recommended to use GB/T6109.2-2008 “Polyester Enameled Round Copper Wire, Class 155,” GB/T 6109.5-2008 “Polyester-imide Enameled Round Copper Wire, Class 180,” GB/T 6109.6-2008 “Polyimide Enameled Round Copper Wire, Class 220,” or GB/T6109.20-2008 “Polyamide-imide Composite Polyester or Polyester-imide Enameled Round Copper Wire, Class 220.”
Ngoài ra, Cấp 1 enameled round copper wire as specified in these standards can be used, provided it passes the relevant tests outlined in the standards.
After winding, an appropriate impregnating agent should be used to enhance the insulation properties of the windings.
The impregnation process should follow the manufacturer’s specified method, using techniques like dipping, trickling, or vacuum pressure impregnation (VPI) to fill the gaps between winding wires and ensure strong adhesion. If the impregnating agent contains solvents, the impregnation and drying should be performed twice to allow solvent evaporation.
Nói chung là, methods like spraying or coating for insulating windings are considered unreliable for thiết bị điện chống cháy nổ. Adequate attention should be given to this in engineering practice.
Hơn thế nữa, for high-voltage windings, the impregnated windings should be treated with anti-corona paint to prevent additional hazards caused by corona discharges.
In enhanced-safety electrical devices, whether motors, electromagnetic coils, or other equipment’s coils, they should generally be equipped with nhiệt độ protection devices to prevent exceeding limit temperatures under normal operation or recognized abnormal conditions.
If a winding does not exceed the limit temperature under continuous overload (such as a motor rotor lock), or if a winding is not subject to overload (like a ballast for fluorescent lamps), then it does not require a temperature protection device.
When enhanced-safety electrical equipment is equipped with temperature protection devices, these can be installed either internally or externally. Regardless, the protection device should have the appropriate loại chống cháy nổ and should be assessed in conjunction with the protected equipment.