Replacement Branson 902J converter For 905,910 D/M (500 and 1000 watt) power supplies and welder model 910 IW and 910 IW+ Part No- 101-135-047 The CONVERTER is the motor of the ultrasonic welding system. This component produces a motion via a piezoelectric effect, which is to say that the converter expands and contracts when electrically excited by the power supply. At 20 kHz, this expansion and contraction is approximately .0008 of an inch or 20 microns at the face of the converter and the movement is in an axial motion. The converter is matched to the output frequency of the power supply. There are different converters for 15, 20, 30 & 40 kHz ultrasonic welders. See less