The medium frequency power supply below 1000kW for the medium frequency furnace generally adopts three-phase five wire 380V, 50Hz industrial power, and is equipped with 6-pulse single rectifier medium frequency power supply; That is, ordinary power transformer is OK. For the medium frequency power supply above 1000kwy, the focus is on using the incoming line voltage above 660V (some manufacturers use 575v or 750V, because 575vz or 750V is a non-standard voltage level, it is difficult to choose accessories, so it is recommended not to use). The 12 pulse dual rectifier medium frequency power supply is a 12 pulse transformer.
There are two choices for the incoming line voltage of intermediate frequency furnace
1、 The rated working voltage is increased by increasing the incoming line voltage;
2、 Second, the harmonics generated by high power will interfere with the power grid. A relatively flat DC current can be obtained through double rectification. The load current is rectangular wave, and the load voltage is close to sine wave, reducing the impact of power grid interference on other equipment.
Do not blindly pursue high voltage
Some users blindly pursue high voltage (some 1000kW use 900v incoming line voltage) and achieve the purpose of energy saving since low current. Do you know that this is at the cost of the service life of the electric furnace, and the gains outweigh the losses. High voltage is easy to shorten the service life of electric components, copper bars and cables, which greatly reduces the service life of the electric furnace. In addition, for electric furnace manufacturers, high voltage reduces raw materials and saves costs. Medium frequency furnace manufacturers are certainly willing to do so (high price and low cost) The final loser is the foundry manufacturer.