Refractories with melting point higher than 1700 ℃ can be classified into six categories according to chemical composition: oxides, carbides, nitrides, sulfides, borides and chemical elements.
IGBT will be exposed in the maintenance of switching power supply, so how to measure the quality of IGBT with Multimeter? There are three steps to measure the quality of IGBT with a multimeter:
Yoke usually refers to soft magnetic materials that do not produce magnetic field (magnetic line of force) and only transmit magnetic line of force in the magnetic circuit. Yoke is generally made of soft iron, A3 steel and soft magnetic alloy with high permeability. In some special occasions, yoke is also made of ferrite materials.
The induction melting furnace must inspect the electrical equipment, the water cooling system ( closed-loop cooling tower ) , the inductor copper tube, etc. before the furnace is opened .
In the forging workshop, industrial furnace smelting metals include cupola, induction furnace, electric resistance furnace, electric arc furnace, vacuum furnace, open hearth furnace, kiln furnace, etc.; sand-type drying furnace with bake sand type, iron alloy oven and casting annealing furnace; In the workshop, there are various heating furnaces for pre-forging heating of steel ingots or billets, and heat treatment furnaces for stress relief after forging; in the metal heat treatment workshop, various annealing, normalizing, quenching and tempering heat treatments for improving the mechanical function of the workpiece Furnace; in the welding workshop, pre-weld preheating furnace and post-weld tempering furnace with weldments;
The most effective method for the failure of the intermediate frequency furnace is to use a small current experiment to judge whether the rectifier circuit is faulty or part of the inverter fault. When the DC current is less than 513 volts
The most effective way for the failure of the medium frequency furnace is to use the low current experiment to judge whether it is the fault of the rectifier circuit or the fault of the inverter part. In the low current experiment, when the DC voltage is less than 513v, it indicates that there is a phase loss fault in the DC rectifier part. Check the specific thyristor fault, and the pulse breaking method should be used to judge whether it is the thyristor fault or there is no trigger pulse.
In the forging workshop, industrial furnaces smelt metals, including cupola, induction furnace, resistance furnace, electric arc furnace, vacuum furnace, open hearth furnace, crucible furnace, etc; There are sand mold drying furnace for baking sand mold, ferroalloy drying furnace and casting annealing furnace, etc; In the forging workshop, there are various heating furnaces for heating ingots or billets before forging and heat treatment furnaces for relieving stress after forging;