SP-15 and SP-25 series are  suitable for the heating of small metal parts, for example, 

 （1）brazing of machining tools

 （2）Brazing of diamond tools

 （3）Heat treatment of small parts

 （4）Melting of gold, silver, copper, brass of little amount

 （5）Melting of steel and stainless steel of little amount.
  SP-15 and SP-25 series machines are acterized with simple structure, high reliability and low price, and are one of the most popular models and have been used widely in every areas of metal heating.

Working theory and structure
    In SP-15 and SP-25 series machines, series oscillating circuit is applied as circuit below, through high frequency transformer, low voltage and high current power is output to go through the induction coil.  SP-15 and SP-25 series machines are the first models developed in our company, SP-15 uses MOSFET components and SP-25 used IGBT components, both use our first generation inverting control technology, the machines are featured with simple structure, high reliability and low price, and they are easy to use and to repair, and are now the most widely used machines both in China and abroad.

Advantages  of Timer function of SP-15A and SP-25A:
   1. Heating power, retaining power, heating time, retaining time and cooling time can be preset and adjusted, this makes it possible to control the heating curve and heating time.
   2. It is suitable to use in the repeated heating or high speed heating of small parts;
   3. When using in brazing, with proper timing parameters, rapid heating and retaining can be achieved to keep the temperature while the brazing material is melted and then to let the brazing material spread smoothly to form good joint.

Advantages  of separated transformer of SP-15B and SP-25B:
    1. In SP-15B and SP-25B machines, the high frequency transformer is separated from the generator, with 2 meters connecting cable at least.
   2. It is suitable to use in the dirty or corrosive surroundings, the generator can be put in a clean space to increase the reliability.
   3. With the small size and light weight of the separated transformer, it is convenient to use in the production line and easily assembled inside the machinery or moved mechanism.