Transistor frequency converter has been made for TRW – DAS JSC Dačice. Together with a mid-frequency transformer and an appropriate inductor it is used for induction heating of the ends of tubes made from magnetic steel.
The operator inserts the cold tubes into the inductor to a fixed stop where the terminal switch is turned on. The terminal switch activates the transistor frequency converter and the end of the tube starts to be heated. When the required temperature is reached the indicator lights up. The set temperature is automatically maintained until the operator removes the tube out of the inductor. When the tube is being taken out of the inductor the transistor frequency converter is automatically switched off.
The frequency converter is controlled by the system consisting of a regulator, converters and Programmable Logic Controller (PLC). The temperature of a heated tube end is measured by a non-contact thermomether UPF V. The converter is operated with buttons and a communication panel placed on the door of the frequency converter. Heating parameters are set on the communication panel where all failures of the heater are displayed in text, including the instructions for troubleshooting.
A part of the transistor frequency converter is a chassis which enables mobility of the whole device.
|Nominal input values|
|Power Input [kVA]||54|
|Input voltage [V]||3 x 400|
|Input temperature [°C]||max. 34|
|Input pressure [MPa]||max. 0,3|
|Pressure loss [MPa]||0,1|
|Maximum warming thru loop [K]||10|
|Nominal output values|
|Nominal output voltage [V]||200|
|Dimensions (d x š x v) [mm]||1100 x 1310 x 1275|
|Technical parameters of heated material|
|Heated material||magnetic steel|
|Dimensions of tubes||Ø D [mm]||40 - 62|
|wall thickness [mm]||4 - 9|
|length l [mm]||300 - 1200|
|length of heated part l [mm]||100|
|Maximum heated amount [kg/h]||155|
|Rated output temperature of heated rod end [°C]||750 - 800|