| 3. Brief introduction of solid state HF welder |
| 3.1 Rectifying cabinet |
| The function of switch cabinet and rectification control are incorporated here as a whole. |
 a.Installed input pole switch, input current meter, voltmeter (can be switched) and input voltage indicating light; |
| b. Installed 3-phase thyristor Rectification Bridge to realize power adjustment of the HF welder; |
| c. Installed smooth-wave reactor, smooth-wave capacitor and filter to improve the smooth-wave coefficient. |
| 3.2 Inverter and output cabinet |
a.The inverter part is made of MOSFET single-phase inverter bridges connected in CFI. The power of single-phase bridge is 60kW; the inverter bridge adopts the building block method to realize power superposition. Every piece of bridge plate is designed in the shape of a drawer, which is very easy to install and repair; |
| b.The matched transformer is adopted for power combination. Also adopted is the output method by use of secondary resonance and non-welding transformer—the tank-circuit resonance capacitor (low voltage) resonates with the sensor directly, and the output pole plate offers required power transmission for pipe welding; |
| c. Also installed sealed equipment cabinet and air conditioner. |
| 3.3 Connecting optical fiber |
| The rectifying cabinet and the inverter output cabinet are connected with optical fiber, so as to make sure control system can not be disturbed by HF signal, which enhances the reliability of equipment. |
| 3.4 Closed loop water cooling system: |
| Air-water heat exchanger is adopted. And recycling soft water is used as cooling water with temperature and water level indicator. |
| 3.5 Central operator console: |
| It provides switch-on/off of the solid state HF welder, power adjustment, as well as PLC system and LCD (liquid crystal displayer). |
| 3.6 Mechanical adjustment device: |
| It is used for installation and adjustment of the inverter output cabinet, and can be 2-D. |
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| 4. Main components list: |
