... protection TypeFrequencyPowerFunctionNotes HNE-FP-T 20~35KHz ≤500WSeparatly excited generator; frequency adjustable, small-signal remote control, over-current protection ... protection, power and frequency adjustable, timer optional . Portable typeNotes: In generator type: HNE-FP-X,F means frequency, P means ... For example: HNE-20500-N, This model of generator is applicable to transducer of 20K, 500W