Talking about changing electric welding machine into flameless welding machine

This flaw.

The rear stage of the power amplifier adopts OCL circuit, which consists of a pair of high-power pair of tube groups

to make. The tube models are: MJ11032 and MJ11033, which are produced by the MTOROLA company in the United States. The BVeco is 120V, the maximum output current is 50A, the dissipated power is 300W, and the characteristic frequency is 30MHz.

Component selection: 6N11 uses products from Beijing Shuguang Factory, available

6DJ8,6922 and other direct replacements, of course, the tone is also available, and the price is only

―Replace half of 6N3, but this is much slower. R3, R4

It is better to control the resistance error within 99.9% by measuring the voltage value at point A to see if it is half of VB2. Coupling capacitor C 丨 Best

Use MKP capacitors with a withstand voltage greater than 450V, or use WIMA capacitors or CBB starting capacitors in washing machines instead. Unless otherwise specified, the resistance

I use 1 / 4W metal film resistors. MJ11032 and MJ11033 should use original US products, and the words * MEXICO * printed on the market

This kind of tube is less effective.

If the filament is powered by AC, the sound is more mellow, but the exchange sound

It is not easy to deal with, at this time, the method can be solved by grounding one end of the filament.

Because the circuit of this power amplifier is simple, in order to complete the work as soon as possible, the author adopts all

The connection was made by scaffold welding, and as a result, there was no background noise

sound. When static, no noise can be heard at a distance from the speaker lm.

The overall impression after the audition is: the tone is full and full, which makes people long

Tired of listening, when using a common CD player as the sound source, there is no "digital" sound at all,

The sound is natural and smooth.

Talking about electric welding machine *

Change to flameless welding machine

? Long Linming?

Recently, in some magazines, it is often roughly mentioned that the welding machine is changed to flameless

Welding machine to repair the refrigerator, that is, using the primary and secondary windings of the welding machine or another

Add secondary winding, and then use insulating rods, copper rods, carbon resistance, etc. to make welding tongs,

This welding machine can be used to weld large parts, if used to weld the copper of the refrigerator

Tubes, especially capillaries, the welding tongs are broken as soon as they touch the copper tubes, so

It is very inconvenient in welding. After many experiments, I transformed the

The flame welding machine was introduced to friends in remote areas for reference and guidance.

Use bidirectional thyristor to control the power supply in the welding machine

SCR can control the conduction of the anode and cathode in both forward and reverse directions),

In Figure 1, the primary and secondary coils and iron core are from the original welding machine, 3CTS is double

To the thyristor, Rw is an adjustable potentiometer, R], R2 is a resistor, C is a capacitor. It can be seen from the figure that the AC loop controlled by the triac is inductive

Load, inductive load will cause self-inductance when the power is turned on and off

Potential, voltage rise rate is large, it is easy to cause thyristor to misconduct and damage

Bad, so the following should be paid attention to when using inductive load bidirectional thyristors

Point: (1) The selection of the turning voltage of the component, the forward and reverse rotation of the bidirectional thyristor

The folding voltage is greater than the peak voltage of the power grid; (2) Selection of component rated current

The rated current of the bidirectional thyristor is calculated by the effective value, so the yuan

The selection of the rated current of the piece should be greater than the effective value of the maximum load current; (3)

Trigger resistance selection, bidirectional thyristor AC switch does not need to trigger

Road, only one resistor is used to get the trigger signal from the load, but the resistance is too large

It cannot be triggered. The trigger resistance can be measured according to the circuit shown in Figure 1.

After the switch K is turned on, adjust the potentiometer Rw to make UAC drop. For power supply

For a circuit with a voltage of 220V, the UAC can be adjusted to 1 ~ 5V. At this time, the total resistance R is measured

+ R1 is the trigger resistance, R

——Generally 330n ~ 30kfl, power is less than 2W; (4) In order to limit the rate of voltage rise,

Inductive load, resistance and capacitance protection should be added between the anode and cathode of bidirectional thyristor.

General R2

Welding tongs with paper beech or other insulated saws from waste power transformers

Two 15cm long spares. Install a copper rod in the paper rod, and put one end on the copper rod

File a small hole, install a carbon resistance in the hole, connect the other end of the copper rod to the original welding machine

The copper wire is connected to both ends of the output of the welding machine (see Figure 2).

Figure 2 Welding tongs

After such changes, the large parts can be welded by adjusting the potentiometer Rw,

Can also weld small parts, at the same time, suitable for welding copper, iron, aluminum, tin and other metals

Pick up. Because there is no flame and no solitary light in welding, it can be clearly seen

Adjust the potentiometer by the position of the soldered spot and the optimal temperature required by the soldered spot. This welding machine does not require oxygen and acetylene. Only need to connect to 220V city

Electricity is very safe in use, plus small size, high power and light weight,

Therefore, it is very suitable for mobile maintenance. If there is no electric welding machine, the old iron core of about 1kW can be used for self-winding.

Simple and easy delay timer

The cycle timer can be adjusted to start and stop time, up to 2 hours, the most

Short to 5 minutes, and there is a function to delay the start of 5 minutes, especially for refrigerators

(Freezer) and other refrigeration equipment is the most practical, and also has a quick start button, such as

Plug in the refrigeration equipment and start immediately, then press the quick start button to start

Make. The cycle timer can also achieve the purpose of saving electricity, such as refrigerator freezer

When the internal food decreases, the start time knob can be adjusted to shorten the boot time

Short, the downtime is extended, which saves electricity and has

Cabinet) has played a protective role, because it reduces the number of start and stop. When the refrigerator

(Freezer) During normal operation, the power grid suddenly lost power. After less than 5 minutes,

Contact voltage 250V, a single group of contacts; two 5kO adjustable potential

Device (available with a small knob); 1C is a programmable timer CD4541B; other components have no special requirements, see the circuit principle for specific models

Figure as shown in Figure 1.

How to use: Connect the timer to the power supply, the red light is on and the red light is on

For power instructions, plug the refrigerator (freezer) into the timer socket

The thermostat gear in the box (freezer) is turned to the highest gear (ie normally open or speed

Cold gear), at this time, turn on the time adjustment knob to the appropriate time (such as 15 minutes

Etc.), then turn the downtime adjustment knob to the appropriate time (such as 30 minutes

Etc.), if you need to start at this time, press the quick start button, the refrigerator (freezer) can be

Normal work, if you do n’t press the quick start button, the timer will be delayed for 5 minutes

After starting.

As long as the components are qualified and the wiring is correct, the timer is made according to the figure

After completion, it can work normally and reliably.

When a call comes, this time the compressor

It is in a state of pressure, it is easy to damage the compressor, because the cycle timer is delayed

The power supply function can protect the compressor reliably. In addition, the damaged ice on the thermostat

Box (freezer), it is particularly convenient to use the timer as a replacement.

Components: One (60x100) mm2 circuit board is required;

The coil voltage of the electrical appliance is DC Note: Red light: power supply guilt; green light;? For small finger; yellow light: stop indicator

12V, contact current 5A, 01 Siam control delay loop timing *

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