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Topic: Questions about Arduino spot welder controller (Read 26280 times) previous topic - next topic

Jane1

@candido


Can you please let me know further details about  your secondary  winding? What wires did you use?What  cross-sectional area  ?

 I do not understand this
Quote
In 3 secs there are 100 power mains half-waves (assuming 50 Hz).
But I think in 1 sec there are 50 waves. in 3 sec there are 3x50 =150 sec
Or am I wrong?
Thanks for feedback.

candido

#31
Jan 16, 2016, 03:06 pm Last Edit: Jan 16, 2016, 03:20 pm by candido
@candido


Can you please let me know further details about  your secondary  winding? What wires did you use?What  cross-sectional area  ?

 I do not understand thisBut I think in 1 sec there are 50 waves. in 3 sec there are 3x50 =150 sec
Or am I wrong?
Thanks for feedback.
Sorry, I meant to say "In 3 secs there are 300 power mains half-waves (assuming 50 Hz)." This will then lead (to achieve 200C) to 300/7.5 = 40 half-waves/3 secs or about 13 or 14 half-waves/sec

Regarding the secondary widing, just google for "MOT rewinding", there are plenty of youtube videos showing how to do it.

footbaldd

Hello, I am rather interested in ordering one of your spot welder control boards. I am located in the US, but would like to purchase a few in the near future.

I was wondering if I could you could explain a few thing for me. What is the benefit of the zero-cross/ quarter hertz time circuit? Does this accomplish power factor correction? What kind of welding is most benefited by this method of control? I want to do both parallel electrode battery spot welding and opposing electrode sheet metal, along with possibly doing resistive to non-resistive spot welding for heater elements.

I already have a 1100 watt transformer wound and mounted with my setup, but was originally going to use a foot switch and power switch to control a relay on the mains. I decided that I might be better with an ssr/scr diode when I found your page.

That you for your time, and I will be anticipating your response. Have a good day.

Also after a bit of thinking I have an additional question to ask. When you look at the power side of this system, it is essentially a purely inductive/resistive load. When I disassembled the microwave that I stole the transformer core from, there was a rather large capacitor that looks to have been paired with the magnatron. This would make sense in terms of overall efficiency since the reactance of the capacitor would help to bring the power factor of the unit closer to a unity pf. Wouldn't it make sense to employ some sort of pf correction to this design?... It seems that if this was to be done, then the zero-cross/pulse time trigger would need to be rethought.

avandalen

>>>I was wondering if I could you could explain a few thing for me. What is the benefit of the zero-cross/ quarter hertz time circuit? Does this accomplish power factor correction? What kind of welding is most benefited by this method of control? I want to do both parallel electrode battery spot welding and opposing electrode sheet metal, along with possibly doing resistive to non-resistive spot welding for heater elements.

It is just for educing the weld transformer inrush current.

>>>I already have a 1100 watt transformer wound and mounted with my setup, but was originally going to use a foot switch and power switch to control a relay on the mains. I decided that I might be better with an ssr/scr diode when I found your page.

You can't control weld times by a foot switch, weld times are sometimes just 50ms.


>>>Also after a bit of thinking I have an additional question to ask. When you look at the power side of this system, it is essentially a purely inductive/resistive load. When I disassembled the microwave that I stole the transformer core from, there was a rather large capacitor that looks to have been paired with the magnatron. This would make sense in terms of overall efficiency since the reactance of the capacitor would help to bring the power factor of the unit closer to a unity pf. Wouldn't it make sense to employ some sort of pf correction to this design?... It seems that if this was to be done, then the zero-cross/pulse time trigger would need to be rethought.
[/quote]

PFC doesn't make sense I think because the weld times are very short. The capacitor is a high voltage type and not designed for PFC.

matt4x4

Hello, I bought your pcb board and parts, ordered the other parts needed from ca.mouser.com and soldered them all up. It was real easy to solder the through-hole parts. I just had to google which way the LED diode would go, I dont think that big red capacitor in the corner is polarized is it?
I put mine printed label outwards.

I found a transformer out of a Fridigaire 1100W microwave, also have 2 other smaller transformers out of 2 different microwaves. I will use the 1100W for battery tab welding and follow your website on building one.

On a side-note: Can I use this board as a Auto Transformer/Variac, the instructable said I needed any "Solid State Dimmer for inductive loads" this is for an Arc Welder, using 2 modified transformers in series.
http://www.instructables.com/id/Build-a-Microwave-Transformer-Homemade-Welder/
I was wondering, with your knowledge, do both of these transformers have to be exactly the same or can they be different?



Thanks

avandalen

Hello, I bought your pcb board and parts, ordered the other parts needed from ca.mouser.com and soldered them all up. It was real easy to solder the through-hole parts. I just had to google which way the LED diode would go, I dont think that big red capacitor in the corner is polarized is it?
I put mine printed label outwards.

I found a transformer out of a Fridigaire 1100W microwave, also have 2 other smaller transformers out of 2 different microwaves. I will use the 1100W for battery tab welding and follow your website on building one.

On a side-note: Can I use this board as a Auto Transformer/Variac, the instructable said I needed any "Solid State Dimmer for inductive loads" this is for an Arc Welder, using 2 modified transformers in series.
http://www.instructables.com/id/Build-a-Microwave-Transformer-Homemade-Welder/
I was wondering, with your knowledge, do both of these transformers have to be exactly the same or can they be different?
The flat side of the LED is the minus
The big red capacitor in the corner is not polarized
>>Can I use this board as a Auto Transformer/Variac
Maybe, I have not figured this out, but you can use it for solid state relay and maybe for dimmers too with custom software.
>>do both of these transformers have to be exactly the same
When the transformers are in series, I suppose this it no problem.




Thanks

Dimoncik23

Hello it possible to buy already build board and how ?

stevebowen

I purchased the 2015 board and the programmed chip
and then purchased all parts except the block transformer from Mouser
I got the block transformer from amazon but ordered the incorrect but very similar 2, 0/1/9 transformer
when I should have ordered the 2, 0/2/9 version.
The basic difference is that the version I ordered has only one secondary coil not two.
The primaries are identical.

I started by installing the mains connectors, transformer, bridge rectifier, voltage regulator and electrolytic
filter caps.  The transformer became very hot and I could get no output from the voltage regulator
(expected 5vdc) so this is when I eventually discovered the incorrect transformer.

I removed the transformer and tested it separately and it appears to work correctly so removed the
bridge rectifier and voltage regulator and reinstalled the transformer and it works fine.

So at this point I think either the 2, 0/1,9 or 2, 0/2/9 transformer should work ( the /1 does not have a
pin 8 to cut.

So now I will have to get a new bridge rectifier and voltage regulator and test these in circuit.

Not sure what went wrong the first time

avandalen

Hello it possible to buy already build board and how ?
No, I haven't assembled boards.

avandalen

I purchased the 2015 board and the programmed chip
and then purchased all parts except the block transformer from Mouser
I got the block transformer from amazon but ordered the incorrect but very similar 2, 0/1/9 transformer
when I should have ordered the 2, 0/2/9 version.
The basic difference is that the version I ordered has only one secondary coil not two.
The primaries are identical.

I started by installing the mains connectors, transformer, bridge rectifier, voltage regulator and electrolytic
filter caps.  The transformer became very hot and I could get no output from the voltage regulator
(expected 5vdc) so this is when I eventually discovered the incorrect transformer.

I removed the transformer and tested it separately and it appears to work correctly so removed the
bridge rectifier and voltage regulator and reinstalled the transformer and it works fine.

So at this point I think either the 2, 0/1,9 or 2, 0/2/9 transformer should work ( the /1 does not have a
pin 8 to cut.

So now I will have to get a new bridge rectifier and voltage regulator and test these in circuit.

Not sure what went wrong the first time

I have figured it out, the AVB 2,0/1/9 works also, so thats fine. I suppose womething went wrong with other components.

stevebowen

I believe that I installed the bridge rectifier backwards

Medmike

The AVB 2,0/2/9 has 10 pins according to data sheet.  Any pin not lined up with the 6 thru holes on circuit board need cut then, correct?  Not just pin 8?

stevebowen

I have completed my board power supply and microcontroller sections.

When I power up the board the led blinks 4 times and then turns on steady.

The troubleshooting section says it should blink 2 times

what is the reason for this?

stevebowen

Okay so flashes 4 times at start vs 2 times
but when I press the weld button it turns off for the appropriate amount of time depending on the time
selection.  also can select continuous weld per instructions.

but completed the assembly connected control board to MOT transformer wound with 3 turns in the secondary

but the primary cord was shorted at the primary terminals so when I pushed the weld button it blew the side out of T1.
I will change both T1 and T2.

avandalen

Okay so flashes 4 times at start vs 2 times
but when I press the weld button it turns off for the appropriate amount of time depending on the time
selection.  also can select continuous weld per instructions.

but completed the assembly connected control board to MOT transformer wound with 3 turns in the secondary

but the primary cord was shorted at the primary terminals so when I pushed the weld button it blew the side out of T1.
I will change both T1 and T2.
Yes it flash 4 times now, I changed that in the article too.

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