Keywords: spot welding machine circuit diagram
This article describes the use of tube transmitter transformers to make spot welding machines, and the FU-60Z filament transformer of 10kW FM transmitter is taken as an example.
First, the structure of Fu-60Z filament transformers
The filament transformer is a current limiting transformer to keep the filament initial current below the maximum predetermined value. This transformer is shown in Figure 1. Unlike ordinary transformers, there is a magnetic division in primary-side. When the magnetic flux flux is extremely small when the load is increased, the secondary security number increases the magnetic flux through the magnetic branch, which reduces the magnetic coupling between the primary and secondary windings, thereby decreased The secondary output voltage, the general characteristics are shown in Figure 2. At the moment of turning on the filament, the electrical tube filament is extremely small (cold resistance), and the transformer secondary load current is close to the short circuit current, and the secondary voltage is very low, close to zero volts. Since the secondary filament is low, and the secondary fails to get the primary energy (because the reason is due to the result of the magnetic branch). The start current of the filament is reduced, and the use of the spot welder must be modified to remove the magnetic bouncing core.
Second, the principle, performance and requirements of spot welding machine
When two-sided double-point overcurrent welding, the two electrode pressurized workpieces form a certain contact resistance at the pressure of the two-layer metal at the pressure of the two electrodes, and the welding current flows from the electrode in two contact resistance points when the other electrode is formed. Instantaneous fusion, no injury and internal structure of the soldering workers. In order to obtain a solder joint with a certain strength, the welding time and the welding current can be supplemented with each other within a certain range. Small current and long periods can also be used with large currents and short time. The mode of use depends on the performance of the metal, thickness, and the power of the welder used.
Welding do not have to be used when welding. High temperatures generated by contact resistance. Mel the metal instantly welded together.
Third, the scope of application of spot welding machine
1. The connection between the wire and the guide. 2. Welding of various types of rechargeable batteries and 0.03 mm to 0.3 mm. 3. Household appliance parts and wire welding. 4. Welding of various high or low conductivity metals and alloys. 5. Cutting of foam, plastic, organic glass.
Fourth, the principle of work of the self-made spot welder circuit
As shown in Figure 3. B2 is a step-down transformer and is the core component of a welding machine.
380V AC PC will output 15V AC voltage by transformer B1. Provides the + 12V operating power supply of this circuit. The NE555 time-based circuit forms a multi-resmium to control the on and off of the SSR. When the + 12V supply is supplied to NE555, since the voltage on the capacitor C3 cannot be mutated, NE5552, 6 pin is low, then the 3 pin outputs a high level. The + 12V power supply is charged to the capacitor C3 by R1 and RW. When the NE5552, 6 foot potential reaches two-thirds of the power supply voltage, the NE5553 foot output level is low from high. Work indicates that the light-emitting diode V2 is turned on. The output of the NE555 depends on the conduction of the SSR SSR. The time of trigger pulses each time the AC voltage is turned from zero. Correspondingly, B2 is changed accordingly. The voltage across the B2 primary winding is changed. The purpose of the adjustment control secondary output current is reached. The secondary packed resistors can be used for cutting machines, used to cut foam, sponge, plastic, plexiglass, etc.
V. Selection and use of devices
The step-down transformer B2 is a filament transformer of a 10kW FM transmitter. The rated power is 1900W. The primary AC voltage is 380V. The secondary AC voltage is 5V. The rated output current is up to 190A. SSR is GTJ-5A / 380V solid state relay. Considering the current of the secondary output. The welding wire should be used as a copper core, and there is enough cross section to ensure that it will not be hot due to overload during use, and the carbon rod (graphite) is made into a tapered welding torch. The potentiometer RW1 is used to adjust the suitable welding current, and the line part of the mains with the maintenance is reliable. Welding wires and welding machines, welding tongs are connected to apply bolts, nuts, plus the washer and tighten.
Finally, it is dote that the circuit assembly is to be placed in a suitable metal case, in addition to ensuring good ventilation, the entire circuit should be well insulated from the outer casing. At the same time, the outer casing should be reliably grounded. A large amount of spark is sprayed due to welding. The welding temperature is also very high. For safety, it is necessary to stay away from flammable and explosive items when welding. Outdoor homework should pay attention to rain.
Author: Ji Chengquan
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