The VSDS shall be suitable for use in a saliferous, sulfurous and dusty atmosphere.The rated voltage of VSDS will be 690V or 400V, 50Hz, 3-phase, TN-S system. Single-phase VFDS may only be used for special applications after approval by Owner. The voltage vibration will be within ±10% of rated voltage, while frequency vibration will be ±1% of nominal frequency.