Technical knowledge related to the power of medium frequency induction heating equipment

Today, the editor will briefly explain to you the technical knowledge related to the power of medium frequency induction heating equipment, including a brief introduction to power dividers, power switchers and online net power monitors.

1. What is a power divider? Power divider is also called power pulse. When using a semi-ring type inductor to heat the crankshaft journal fillet, due to the large difference in mass of the metal next to the journal's top dead center and bottom dead center, the absorption of magnetic lines of force and heat transfer effects are also different. If power distribution is not performed, the heating effect is that the temperature on both sides of the top dead center of the journal is higher than the temperature on both sides of the bottom dead center. The difference is related to factors such as power density, crank structure, and effective ring structure.

The so-called power distribution means that during rotational heating, when the center of the semi-ring inductor is at the top dead center of the journal, the power it applies is smaller than when it is at the bottom dead center. This adjusts the original high temperature at the top dead center. The difference with the low bottom dead center temperature. There is a kind of power divider that is a mechanical device that combines a set of limit blocks and a set of proximity switches. As the crankshaft rotates, the bracket moves up and down. The limit blocks fixed on the bracket make the proximity switch act, and the proximity switch controls The size of the intermediate frequency power can change its power during each rotation of the journal. Generally, the power at the top dead center position is about 30% less than the power at the bottom dead center position, and it can be adjusted and determined according to the specific situation. Another method of cooling the top dead center is local watering. Through the cam that collides with the crank, the cooling water is poured only to the top dead center area.

2. What is a power switcher? When one induction heating power supply supplies multiple quenching machines or quenching stations, a power switcher is required. They are interlocked by the control circuit and will not be switched on at the same time. Its main circuit contacts are equivalent to knife switches, which are opened and closed by pneumatic or electric components. This kind of switch generally does not have an arc extinguishing cover, so it can only be switched when the power is off. Its size is small, much smaller than the medium frequency contactor used in the 1960s. At present, domestic power switchers include two-table power switchers and three-table power switchers.

3. What is an online net power monitor? The workpiece net power monitor is used to monitor the quality of the raceway hardened layer online in real time during the quenching process. When the gap between the sensor and the workpiece changes due to distortion, this monitor can accurately reflect the power on the heated workpiece. Variety. The power changes reflected by the monitor are different from the power changes measured on the conventional oscillation loop. It filters out stray power losses, so it is called a net power monitor. When the gap changes by 0.2-0.4mm, the oscillation loop monitoring curve does not change significantly, while the curve monitored by the net power monitor becomes clearly visible like a magnifying glass. With the net power monitor, small changes in power caused by changes in the gap between the sensor and the workpiece can be displayed and coordinated with the automatic positioning of the sensor.