Application of MOSFET Solid State High Frequency Power Supply in Pipe Welding
According to the comparison of solid state high frequency power supply and electron tube high frequency pipe welding power supply, it could be concluded that solid state high frequency power supply is more efficiency, more security, longer life-span and will replace electron tube high frequency pipe welding power supply in not very long time in this field. In this paper, a solid state high frequency pipe welding power supply using MOSFET as the inverter switch components is designed, its operating principle is analyzed, the key technique of section of rectifier and inverter is discussed and the load adaptability, frequency tracking, output power are explained in detail. From the simulation and experiment, it can be seen that the designed method is reasonable and the whole device is high efficiency
Design of a series resonant converter for induction heating
A generator is presented for induction heating applications whose heating inductor is compensated by a series LC circuit. The inverter works in a continuous manner and the working frequency reaches 250 kHz, providing power of up to 12 kW. Power regulation is performed by frequency variation and the equipment efficiency is greater than 93%.<<ETX>>
Study on urea-modified phenol formaldehyde resin adhesive
A reasonable technology to synthesize Urea-Modified Phenol Formaldehyde resins is realized by reacting phenol,urea and formaldehyde.The resin's feasibility is explored.The experiment result of shows that storable stability of the modified resin is good.The curing temperature of PUF resins was 25 ℃,lower than that of PF resins.The curing speed of PUF resins is faster than that of PF resins at the same curing temperature.The physical properties of the birch plywood bonded with PUF resins is similar to that of the birch plywood bonded with normal PF resins.The mechanical properties of the birch plywood bonded with PUF resins can achieve the demands of GB/T9846-1988.Free formaldehyde content of plywood is lower than the E1 level set by GB18580-2001.The cost of the adhesive is lowered for the use of urea,and its comprehensive properties is better than that of PF resins.