No-load power-saving circuit of AC welding machine.

[prabrahim]

Sir,
I have built this circuit, i dont know, whats going wrong, when i switched on, the transistors got heated and got short,
the IC's getting hot on 12V supply.


on operating on 6V supply, the circuit worked well, but dint operated with the welding transformer

Pls help

website: No-load power-saving circuit of AC welding machine - Free Electronic projects & 8085 projects

 

[DeepOne]

Hi, Prabrahim
I suppose it is necessary to add 12V integral stabilizer of the voltage after diode bridge and filterring capacitor

C4 must be not electrolytic

 

[prabrahim]

sir,
i had used a regulator 7812 with 0.1 mfd on both input and output of the regulator

 

[DeepOne]

well, then it is necessary to take in hands tester and measure the state of working component.

may be 12V zener not really 12V.

 

[BradtheRad]

This is a clever circuit and practical as well.

However it puts low-power circuitry in close contact with high power...

In such a case you need to ensure cooperation between the two.

This circuit should be tested in sections. The timer circuit should be tested for proper operation without being hooked up to the welding circuit.

Then take the next step. Wrap a few turns of coil L around the welding cable. Notice that the coil L is not directly connected to the welding cable. It's only wrapped around it.
Wrap just enough turns to result in a usable signal to pins 2 and 6 of the 555 IC.
Do some welding. Stop. See if the machine turns off at the end of the timed delay.

I have doubts about the wire containing switch K2. It connects delicate components to the welding cable. When welding stops, the transformer coil may generate a hi-voltage spike. This may destroy the timer devices. Maybe it happened already.

I suggest adding a resistor in that wire between welding cable and K2. Start with a high ohm. Reduce resistance until you get proper operation.