Medium frequency generator
Generally to say, We do not have whole set of SPZ machines in stock, we have stock of only SPZ generator, whereas the capacitor and heating coil or heating furnace will be designed and manufactured as per the work pieces and heating requirement of customers.
We need below information from customer for consultation and purchase:
(1)Material and dimension of the work piece to be heated,
(2)Heating application and speed, heating time required; total piece heating or only surface heating? If surface heating, how much thickness? Etc.
(3)Any restriction on the shape and size of the coil? If it is heating from inside or outside? If the coil is enclosed or C-shaped? Is there any metal material easily induction heated within100 mmfrom the coil?
(4)Any requirement for the frequency?
(5)Heating environment: in open air or vacuum? Is there any protection gas?
(6)Any other detail in relation to the machine design?
As shown in below drawing and picture, MF generator and capacitor are the basic constituent of one heating machine.
This is the most popular combination widely used now, for example, the M.F. forging furnace and melting furnace. Machine of this kind is simple, low cost, high efficiency.
In this combination, the coil is large or long, usually 3 to 10 meters long copper tube is needed to turn the coil. There is 550V high voltage directly between the coil and is not safe. So to ensure the safety of the operator, the coil must be insulated properly.
Generators are our standard products which can work at frequency of 1-20KHZ automatically. We need to design and customized the capacitor and heating coil according to the heated parts and requirements to achieve best heating effect.
1、Working theory and main acteristics:
（1） Parallel oscillating structure is used for SPZ generator, it is easy to get the best matching of the machine to get high heating efficiency and full power output of generator. Shuangping MF generators can directly replace the SCR MF generators.
（2） Inside the SPZ generators, IGBT module and our fourth generation inverting control technology has been used, that is the soft and dual control and inverting technology on the basis of parallel oscillating circuit. In this technology, output power and frequency can be controlled and adjusted separately, IGBT module and soft switching control technology are used in the high frequency switching circuit to control the output power. In the inverting circuit, the IGBT and frequency tracing circuit is applied to achieve high speed and accurate soft switching control. The adoption of new technologies not only improves the quality and reliability of the machine，but also solve the technology problem on large power induction heating machine and makes it possible to work 100% duty cycle.
（3） Wide frequency range from 500HZ—20KHZ to make it possible to adapt different heating application and penetration desire.
（4） Soft switching control system lead to higher reliability and lower repair cost.
Medium frequency machines are usually used in the penetration heating occasions, For example,
（1）Rod heating for forging
（2）Melting of almost all kinds of metals
（3）Heating of stators or rotors for fitting
（4）Heating of tube end for extrusion
（5）Heating of moulds
（6）Deep quenching of shafts and gears
（7）Tempering or Preheating of weld-joint and etc.
We generally supply MF generator and capacitor box as the picture shown below, generator and capacitor is connected with co-axial cable, and water cooled cable is used to link capacitor and coil.
Special orders can also be customized as below:
1、Generator + Mini capacitor
Models with Mini capacitor is defined as SPZ-XX-Ⅱ，for example: SPZ-35-Ⅱ；
Below are two kinds of capacitors commonly used: regular oil immersed capacitor and new film capacitor (small cap).
When small capacitors are used, the dimension and weight of the output unit or the capacitor box decreased. If small capacitor is used in the heating machine of SPZ-B2-II series, the capacitors and the coil can be installed together, without the water cooled cable. This way the power loss is decreased a lot, and the machine heating efficiency is higher. As shown by below figures:
By contrast, regular machine is connected this way:
Since the capacitor box is big, usually water cooled cable is used for the connection to the coil, the cable is 1 to 2 meters long, or even longer. The current through the water cooled cable is same as current on the coil, usually as high as 1000～5000A. The higher power the machine is, the higher the current through the coil. So you can imagine how big the power loss is on the water cooled cable. This problem is solved by using small capacitors, and heating efficiency is raised a lot, the machine is power saving.
2、Single Cabinet Machine
SPZ Generator and capacitor supplied by Shuangping are mostly dual cabinet, but Single cabinet machine can be made as required by customer. Refer to the picture below:
The advantage of the single cabinet is space saving, easy installation and without problem caused by connection cable.
3、 Different Control and operation panels
(1) Normal SPZ front panel:
Since most of MF induction heating is long time or continuous working, normal front panel is installed on the machine, as indicated below pictures. With only start and stop button, and power adjust knob, it is easy to operate.
(2) Front Panel with timer:
As Picture below, apart from Start, Stop buttons, Timing function is added, the power and time of the two heating process are adjustable.
When purchasing, if you put “A” on the Model, it means to the front panel with timer, for example, Model SPZ-45AB is with timer function.
（3） Front Panel of current/voltage/frequency/power four display
For standard SPZ-B front panel, there is only one display meter, to indicate the value of voltage or power, by putting the relative button to read the value of frequency or current.
Refer to the picture below, two types of front panel is available to order to display four parameters at same time. Front panel on the left is with additional heating timer function.
(4) Touch Screen operation panelAs indicated below, it is available for all models. With PLC control and touch screen operation panel, it offers multi operational interface, with function of pre-set and storage of process data.
4、 Different input voltage
Our standard machines are design for 3*380V input voltage and 50 or 60HZ； Following input voltage machine can be customized: 3*400V, 3*415V, 3*440V, 3*460V, 3*480V and 3*220V.