1: Anti-spark machine When spark occur, the high sensitiveness spark protects electric system, cuts the high frequency power immendiatly to protect the mould and material 2: Jamming prevention device Equipped with frequency stabilizer and high frequency magnetic leakage suppressor, this device previce leakage of electromagnetic radiation to avoid jamming other electrical instruments such as television and radios etc 3: Safety device When the current exceeds its limit, the overload relay functions automatically, to protect osscillation tubes and reftifier, frequency deviation caused by misoperation is also prevented. 4: Mechanical structure of the special
