Product Name: Quenching Machine Tool

This machine tool is mainly suitable for induction quenching of various shafts, discs and special-shaped parts.

The machine tool adopts numerical control system to realize precise control of quenching speed and position, which can meet the quenching process requirements of workpieces to the greatest extent.

Main characteristics of machine tools:

1.The numerical control (PLC) system is easy to operate and intuitive to display, and can compile and store various heat treatment process programs according to different process requirements of workpieces.

2.Quenching heating and cooling water control interfaces are reserved in the control system, which can control the whole heating and cooling process of workpieces according to process requirements.

3.The workpiece is rotated by frequency conversion, and the main mechanical lifting drive is driven by AC servo. The feed speed is uniform and accurate, and the quenching quality is stable.

4.The lathe bed adopts steel plate welding structure, and the whole stress is relieved.

5.The key components of machine tools are made of anti-corrosion and anti-magnetic materials or antirust treatment.

6.Quenching methods of this machine tool: continuous heating spray quenching, sectional heating spray quenching and one-time heating spray quenching, etc.

Solid-state high-frequency power supply is designed according to continuous operation system. The STC single chip microcomputer system realizes the integrated interlocking control and fault diagnosis functions of the whole set of equipment, and monitors the running state of the equipment through digital display. The following is a brief description of the structure and performance of each component:

1. high power factor rectifier cabinet

The rectifier cabinet adopts PWM switching power supply to improve the power factor of the equipment, and the DC side adopts flat wave reactance as a filter to meet the working requirements of the inverter (current-mode inverter), so as to reduce the output voltage pulsation of the equipment and improve the ripple coefficient index.

The output ripple coefficient of the whole machine is not more than 1%, which ensures the melting quality. Because the magnetic core transformer is used as the secondary power supply for isolation, and the PWM switching power supply and the flat wave reactance are used as filters for rectification, the interference of harmonic components of the power grid to the equipment is avoided.

2. Inverter output cabinet

The main power device is IRFP460 of IR company and DSEI60-06A fast recovery diode of IXYS company.

The output power of single-layer power module is 50KW, and the whole machine adopts multi-layer power modules in parallel. The rated operating frequency is 400KHZ. The same power modules have interchangeability. The power module can work reliably at 600KHZ, so it is very easy to work at 400KHZ.

3. Working principle of solid-state high-frequency equipment

Solid-state high-frequency power supply is actually a low-voltage, high-current, AC-DC-AC variable-frequency power supply, which converts three-phase 380V and 50HZ AC into single-phase high-frequency AC power supply after rectification. The circuit structure is simple. The main circuit rectifier is a commonly used thyristor three-phase fully-controlled bridge rectifier circuit, which uses PWM switching power supply to improve the power factor of the equipment. The inverter part uses MOSFET FET, MA+, MA- and MB+, MB- and MB.

There are only two printed circuit boards for trigger control, one is thyristor three-phase full-bridge control trigger board and the other is inverter control board.

3.1 Comparison between SCR Power Supply and High Power Factor Power Supply

Compare parameters

Silicon controlled phase shift rectifier

High power factor power supply

Controlled device



Working frequency



Control mode

Phase shift trigger


Input filtering



Output filtering



Output DC

Half wave

High density DC square wave

Voltage stabilizing accuracy



Voltage stabilizing accuracy



Cooling mode

Water cooling

Water cooling


Low power factor and high reactive power


Power factor


The whole range can reach more than 0.93

Control circuit

Complex, synchronous and difficult to integrate

Simple, special control board, totally enclosed


Large size, dispersed structure and heavy weight

Small size, compact structure and light weight

Interference to power grid

Big, not easy to eliminate

Small and easy to eliminate

Governor speed

Slow, millisecond level

Very fast, microsecond level

Energy saving effect


Energy saving is obvious

3.2 Principle and composition of high power factor power supply system

3.2.1、Working principle of Buck step-down chopper

When the switch S is turned on, the current flows along the loop 1 to increase the current in L and increase the energy storage to supply power to the capacitor C and the load. When the switch S is turned off, because the current in the inductor L cannot be interrupted, the inductor current continues to release the inductor energy storage along the loop 2. At this time, the diode takes the role of freewheeling, and the current decreases with the decrease of inductor energy until the next switch S is turned on. Repeat this switching operation to achieve the balance of output voltage and current. Controlling the on-off time ratio of the switching device S can achieve the effect of controlling the output voltage. In practical application, the switching device S adopts high-power semiconductor devices IGBT or MOSFET to perform fast switching on-off control; Buck circuit is a kind of step-down circuit, which not only has an output voltage always lower than the input voltage, but also has the advantage of simple structure, which can smoothly adjust the output voltage from 0V and satisfy the following requirements:


In which ton—-chopping pulse width, t-chopping period and d-duty ratio

3.2.2、pulse width modulation  

The meaning of PWM is' pulse width modulation', that is, by continuously adjusting the signal pulse width of a certain frequency, the switching device is driven and the average value of the output voltage or current pulse wave is changed. As for the former Buck chopper, if the switching device S is controlled by PWM signal, the output voltage can work at the required value according to the system control instruction.

BuckChopper switching frequency

f=1/T      f、T

Theoretically, the higher f is, the better. Better filtering effect can be achieved by using smaller LC parameters. The working frequency of low-power switching power supply is often hundreds of kilohertz or even higher, which can greatly reduce the size and cost of the filter. However, the switching frequency of high-power devices is limited, and too high switching frequency will increase the switching loss, resulting in heating damage of switching devices. Generally, the switching frequency of IGBT devices can only reach several kHz ~ tens of kHz.

3.2.3、The equipment adopts the working principle of step-down chopper, and is equipped with multiple protections such as overcurrent, overload, overheating and short circuit to ensure the safe and reliable operation of the equipment. The whole process structure adopts rack design, Infineon IGBT switching device, Epcos electrolytic capacitor and imported chip with high performance for control, which has the characteristics of accurate calculation and small temperature drift, and realizes high stability DC voltage output control.

3.3Technical parameters of high power factor power supply:

Output ripple ≤0.3% (effective value)

Power supply efficiency ≥93% AC-DC

Power factor ≥0.92 (actual test)

Load static adjustment rate ≤0.1%V FSC(0-100%I FSC)

Load dynamic adjustment rate ≤0.5%V FSC

Automatically set the slope for 4 s (adjustable from 0.5 to 30 s)

Fault interlock protection time ≤10μS

4. Some notable features of the fourth generation solid-state high-frequency power supply

4.1 The line is simple and the installation is convenient

After the step-down transformer is eliminated, the connection line between rectifier and transformer is saved, and there are less than ten control connections between rectifier cabinet and inverter cabinet, which is convenient for configuration. There are few connections between the rectified power supply and the console.

4.2 Complete protection and convenient maintenance

The whole machine is provided with more than 20 kinds of protection measures to maximize the stability of equipment and prevent equipment damage. Alarm information is processed by the control panel and sent to STC MCU. Through digital display, maintenance personnel can easily understand the cause of equipment failure and the countermeasures.

The display instructions of rectifier board digital tube are shown in table

Display Content

Meaning of state

Treatment method


High overcurrent

·Check whether the hardware trip circuit of the control circuit board has any action

·Check whether the coil circuit of the main contactor is broken according to the electrical schematic diagram


Low overcurrent

·Check whether the circuit of the control circuit board acts

·Check whether the coil circuit of the main contactor is broken according to the electrical schematic diagram


External fault

·Reserved unused


Power failure

·Check whether the control power supply is out of phase or wrong in phase sequence

·Check whether the fuse of the power detection board is blown

·Check whether the fuse of the power detection board is blown


Cooling fault

·Check whether the pressure of rectifier and inverter cooling water meets the requirements of 0.15 ~ 0.3 MPa

·Check whether the normally closed contact of hydraulic relay is open


Main circuit is broken

·Wait for the main contactor to pull in

·Check whether the normally open point of the main pass control relay is closed


Heating early on

·Heating control advance operation

·Check whether the normally open point of the main pass control relay is closed


Inverter fault

·Check whether the red indicator light of inverter control panel is on, check the digital display, and troubleshoot according to the indicated meaning

·Check whether the wiring of each terminal is loose

·Please contact our technical personnel


Inverter fault

·Used during preliminary machine adjustment


Excessive current

·Check whether the sensor is suitable and in contact with the load wall


Low voltage operation

·The equipment is normal, and it runs with small voltage and current after being heated.

·"D" is displayed when the equipment is powered on and self-checked. Check whether there is any problem with the voltage feedback signal.


Inverter does not start to vibrate

·Check whether there is any problem with inverter cabinet


It is starting to vibrate

·Wait for inverter to work normally

·Check whether there is any problem with inverter cabinet


Waiting for work

·Power-on self-test of equipment is trouble-free, wait for heating to start (normal state)


Normal work

·The voltage-current ratio is normal, and it is displayed when the voltage is greater than 50V

See table for display instructions of phase-locked board digital tube

Display Content

Meaning of state

Treatment method


Power board failure

·Check whether IGBT drive board and comprehensive alarm board have alarm


Tracking lower limit out of lock

·Check the channel connection

·Check the sensor for short circuit


High frequency overvoltage

·Check the sensor and load for short circuit

·Whether the output of the main cabinet is short-circuited or ignited


Too high frequency

·Check the sensor for short circuit and ignition

·Check whether there is short circuit due to scale accumulation in the sensor


Low frequency

·Check the sensor for short circuit and ignition

·Check whether there is short circuit due to scale accumulation in the sensor


Tracking lower limit out of lock

·Check the sensor for short circuit and ignition

·Check whether there is short circuit due to scale accumulation in the sensor


power failure

·Check whether the power supply of phase-locked board is normal


Cooling fault



Rectifier cabinet failure

·Check whether the rectification alarms


Other excited state