Application of medium frequency induction quenching transformer in CNC quenching machine tools

Modern CNC quenching machine tools have many assessment indicators, such as: high efficiency, energy saving, multiple functions, high reliability, automation, online production, practicality, low price, beautiful appearance, environmental protection, etc. The complete set of equipment includes medium frequency induction heating power supply, machine tools, sensors, cooling water circulation system and quenching cooling medium circulation system, etc. In this chapter, the editor will give a brief introduction by taking the application of medium-frequency induction quenching transformers in CNC quenching machine tools as an example.

The function of the medium frequency induction hardening transformer is to reduce the voltage output by the power supply so that it can match the impedance of the inductor and the workpiece, so it is also called a matching transformer.

The number of turns of the primary winding and secondary winding of the early quenching transformer was fixed. For example, the primary winding of the Soviet-style BTO-500 type has 16 turns, 19 turns, 24 turns, 28 turns, and 30 turns. The user can adjust the number of turns according to the number of turns. You need to select and order; BTO-1000 has four turns ratios of 15/1, 15/2, 10/1, and 10/2.

The primary windings of these transformers are all cylindrical windings. Later, in order to facilitate process debugging, the primary winding of the quenching transformer was changed through an external replaceable connecting plate and improved into a multi-turns ratio transformer. The turns ratio range was expanded to 7/1~30/1, 10/1~34 /1 or 10/1~63/1, the structure of the primary winding is also changed to disk shape.

Since most enterprises in my country still use industrial water for cooling water, the water inlet of the transformer is distributed through the water collector to the primary winding, secondary winding, core radiator plate, iron yoke radiator plate and other parts. There are 28 inlet and outlet branch pipes. So much. The advantage is that there are many copper pipe branches, large water flow, not easy to block, and easy to repair; however, there are many pipes and the volume is large, which affects the overall size of the CNC quenching machine tool compared with similar foreign products. Transformers consume a lot of water, with some models reaching 10t/h.

The primary winding of the quenching transformer has many turns, so the cross-sectional height of the copper tube must be reduced. Therefore, the water cross-sectional area is small and the primary winding is easy to be blocked. This problem is more prominent especially when industrial water with high hardness is used as cooling water. The primary winding of the multi-turn ratio quenching transformer is gradually increased from 10 turns to 34 turns. It has a wide adjustment range and is suitable for the production of various products.