Hope your holidays were enjoyable. Thanks for the opportunity to duplicate something great….
I have two questions about the AVEL 625 watt transformer model Y236850 I received today. First of all, the open secondary voltages are 35VAC and not 25VAC. Does this sound right? I have had too many bad or mislabeled parts over the years to not wonder.. Second transformer question. Should both primary windings be paralleled or one primary pair be capped off? I think I saw one pair capped in one of the builders pictures but am not sure. I think it may double the toroidal inrush current if both primaries used. Thanks, Huntersplace
Fritz, Sorry, been bit by this before. Voltmeter battery low resulting in high reading. Still have primary question open. TIP-For those who need a case, a local welding shop sold me a junker for $20. Any existing cords, switches and indicators can be repurposed...
Hunter, manufacturers of transformers sometimes increase the the output voltage slightly to make up for the volt drop when a load is connected but 35V for this transformer is way too high..... I see your voltmeters battery was low and that's why you got the high reading.
Your second question: When you connect the two primary windings in series your primary voltage will double from 110v to 220v. If you connect the primary windings in parallel you are not changing any of the parameters of your formula Vs/Vp = Ns/Np = Ip/Is. Meaning that the turn ratio does not change. It will do nothing to wattage of your transformer. If you connect your primaries in parallel you will have to go to your manufacturers website and look at the schematic to connect it correctly. The easiest way is to use just one primary winding and cap the other one.
Fritz, The open ended secondary voltage is 27VAC. The builder hardwired document shows the double primaries but thanks for clarifying only one primary is needed. The capped primary performs as an autotransformer with input voltage also present on its leads. Regards, Huntersplace
Uhhh, isn't that backwards... the output voltage is proportional to the turns ratio. Series connected PRIMARY windings will cut the output voltage since the effective turns ratio goes down (the series connected windings look like one long winding with double the number of turns).
Parallel the primary windings (or use just one winding) and the effective turns ratio will go up.
When connecting transformer windings in series or parallel you MUST get them phased properly. And you should always use both primary windings (series'd or paralleled( if you want the full rated power output of the transformer.
If you connect the two 110V windings in series you will be able to connect 220V on the primary. Your voltage doubled and so did your windings. If you look at the formula for the voltage of your secondary winding Vs = NsVp/Np and work Vs out with 1 x Primary voltage(Vp) and 1 X primary windings (Np) and then make it 2X primary voltage and 2 X primary windings, you'll see the secondary voltage stays the same. You will get 25V on both secondary windings of this transformer with 115V on one winding or 220V on two primary windings connected in series.
With a parallel connection on your primary or your secondary side your turn ratio DO NOT CHANGE. Two copper wires connected to the same point and turned together in the same direction is the same as one thicker copper wire. The only thing that will happen here is that current carrying capacity will double. The transformer in question here is a 625 Watt transformer with two secondary windings. The two windings connected in parallel will be 25V at 625/25 = 25 Amp. One secondary winding will be 25V at 12.5 Amp. THIS WELDER WORKS WITH A 12AMP TRANSFORMER, DO NOT CONNECT THE PRIMARY WINDINGS AND/OR THE SECONDARY WINDINGS ON THIS TRANSFORMER IN PARALLEL. YOU WILL BLOW THE Q4 MOSFET.
Electrons through a winding flows in a certain direction and the directions of the two windings connected has to be in the same direction or your transformer will burn out.
Happy New Year Fritz! Anything new happen with the pulse arc welder? I've tried running some patent searches on pulse arc welders to see if I could find some info that might help with determining the what frequency is used for the pulses as well as waveform, but there are numerous patents out there and it will take me a while to scan through them. I even ran a patent search on the Ph.D who founded Sunstone Engineering and he does have a patent, however it's not related to pulse arc welding. Is there another possible name/term for pulse arc welding that you can think of that I should try to run a search on? If we can find some patent numbers for the Orion or PUK welders that would be extremely helpful. I might have to find someone on one of the jewelry forums who has one that might be willing to check for the patent numbers on the actual welder.
Hi Ferdi, Its a good idea, I never thought of that. I'm just looking for the waveform, voltage and frequency they use and I will put a circuit together. I have no other information on that at the moment though. I stopped working on my pulse arc welder due to the holidays. I am kind of leaning away to add it to the current capacitor discharge welder and totally redesign the whole pulse arc welder. The reason is so that I can add more functions, save waveforms and much more.
Someone placed a comment a couple of days ago, asking about maybe making the welder with an arc start circuit and not using a solenoid. I didn't think much of it but kind of started to change my mind after thinking about it. I should be able to stop the high voltage circuit fast enough to prevent a shock. Sunstone has a new welder and I do believe it has an arc start.
All these designs take time and my budget is holding me back at the moment.
Hi Fritz, Found an interesting article about MOSFETs, power switching and board layout. Every time I look at my three heat-sinks I cant help but to think about this device. Since you are between designs just some food for thought. The link is: http://powerelectronics.com/power_semiconductors/power_mosfets/power-controller-symmetrical-layout-1107/
I would like to purchase your Spot Welding kit along with design details. Unfortunately no shipping is available to New Zealand. Could you please advise if its possible.
hey matt i plan to fold over the mosfets paralell to the board and use one big heat sink with fins from back to rear just to be different and also hope fully to aid in cooling and possibility conductivity if they are metal backed.
are the fets metal backed mine hav not turned up yet?
also how does he connect the drain and source pins to the aluiminum?
To professor_jonny indeed the 2907's have an exposed die... have not heard of any power switching FET's that dont... but then again I lead a somewhat sheltered life...do you have an example of one without an exposed die? Anyway, 'cool' idea with one big heat sink. I have been researching the idea of liquid cooling but am undecided as yet. It SEEMS fairly easy to make a liquid cooled aluminum block, probably overkill...and too must consider that pesky budget!
the drain and source pins to the aluminum? Not sure if you are referring to the article but I thought it mentioned/showed the pins were bolted down. Do you think it would be better to weld them to the aluminum? I can think of one homemade spot welder that would be perfect for that job.... ;o) MK
Thanks for the url Fritz. I ordered one today. I changed the load resistors from 20 ohms total to 10 ohms total. The liked the quicker discharging. So I tried 6.6, 3.3, and 1.65 ohms total. The discharge at 1.65 ohms total was very quick. The Q4 fet barely got warm even after repeated discharge cycling on 1.65 ohms. But the one thing that was different was that as the charge voltage was being increased, the voltage each time I stopped turning it up, would become very unstable. Q4 would rapid fire at low or high voltages. Is there a correlation between the discharge resistor bank and a narrow hysteresis of the increasing charge voltage?
Mike, I have no idea why you are changing the discharge speed. When you do welds, you won't adjust your welder up and down all the time. You will set it on a voltage and make small adjustments until you find the correct one. You will not even notice a slow discharge. To answer your question. Yes there is a way to change the charging hysteresis, MAKE YOUR DISCHARGE RESISTORS BIGGER.
You talk about changing the discharge speed in the manual Fritz. That's why. Here's the quote "VOLTAGE SET POINT IS LOWERED AND THE 39 OHM 10WATT RESISTERS CAN BE REPLACED WITH 20 OHM 20WATT RESISTERS OR MORE RESISTERS CAN BE ADDED TO MAKE THE DISCHARGE FASTER."
So I made it faster. I didn't know what the limit was so I found out empirically. Because I'm still figuring out the layout of the welder in the chassis, it's nice to be able to discharge the cap quickly so I can get it out of the way. The fet handles the extra load with ease. It looks like the hysteresis was the only downside.
Mike, we have already determine that the car capacitor that you use have a very high discharge current the higher the voltage gets. The processor checks and do an analog to digital conversion on the cap voltage at a specific time interval. This time interval is not always on the exact same time because it has to wait for certain processes to end first before checking the cap voltage again. Your high cap discharge + the low resistance that you have makes it overshoot the set voltage before the processor can check and stop the discharge. Now the voltage is below the set voltage and the processor starts to charge the cap again. That's why you get the erratic behavior. If you use computer grade capacitors your problem will be solved. In the manual for your thermostat at your house it says to turn up the heat when it is too cold, do you turn it up to 100 degrees? No offense, I've been asking the guys not to unnecessary bug me and it seems like you are going to have an issue or are going to ask a question for every wire you are going to connect to your welder. Please use some common sense.
just to note out that 1 of the parts in the bill of materials is marked oboslete and out of stock. c3 and c4 of the control board and c3 of the power section VJ1206Y104KXAMC is an alternative code.
i have also noticed the BC847BLT1 transistor is labled q6 on the bom and q2 on the circuit board no major.
Thanks for the info on the capacitors.. There are lots of replacements for those components and can be easily matched up with components with the same values. BC847 is marked Q6 on the BOM and Q6 on the board, Q6 on the schematic and Q6 on the Block diagram....lol what are you smoking Jonny? :)))
In the manual on page 2 it says not to use Q3 Jonny
lol, i was out on the gas last night a pretzil party where you get free tasting of different spirits to try to sell you it. now reading the manual i see that there are bits that are not required. i just referenced the parts i have from the schematic and noticed there were some missing from the bill all sorted now.
Ed F Hi Fritz I would like to know if you are ordering more boards and if so should i pre pay for the board kit. I think this CD Welder is great and you have done a fantastic job on this welder and a lot of hard work.
I have one full set of boards left https://secure.digitalcontentcenter.com/shop/569822/products/ I will not be selling or ordering anymore boards after this set is sold
hi Fritz, Im wondering on a source for industrial caps and aprox how much they cost you? I have brought several audio caps from a local auction site (trademe.co.nz) and were well below what they were ment to be. i even got a 12 farad cap bank thing and was less than 3 farad after testing!!!
I also wish you well and suddenly you have about the new welder like Lampert PUK
ReplyDeleteJuan M.
Happy New Year, Fritz!
ReplyDeleteFritz,
ReplyDeleteHope your holidays were enjoyable. Thanks for the opportunity to duplicate something great….
I have two questions about the AVEL 625 watt transformer model Y236850 I received today. First of all, the open secondary voltages are 35VAC and not 25VAC. Does this sound right? I have had too many bad or mislabeled parts over the years to not wonder..
Second transformer question. Should both primary windings be paralleled or one primary pair be capped off? I think I saw one pair capped in one of the builders pictures but am not sure. I think it may double the toroidal inrush current if both primaries used.
Thanks,
Huntersplace
Fritz,
ReplyDeleteSorry, been bit by this before. Voltmeter battery low resulting in high reading. Still have primary question open. TIP-For those who need a case, a local welding shop sold me a junker for $20. Any existing cords, switches and indicators can be repurposed...
Hunter, manufacturers of transformers sometimes increase the the output voltage slightly to make up for the volt drop when a load is connected but 35V for this transformer is way too high..... I see your voltmeters battery was low and that's why you got the high reading.
ReplyDeleteYour second question: When you connect the two primary windings in series your primary voltage will double from 110v to 220v.
If you connect the primary windings in parallel you are not changing any of the parameters of your formula Vs/Vp = Ns/Np = Ip/Is. Meaning that the turn ratio does not change. It will do nothing to wattage of your transformer. If you connect your primaries in parallel you will have to go to your manufacturers website and look at the schematic to connect it correctly. The easiest way is to use just one primary winding and cap the other one.
Fritz,
ReplyDeleteThe open ended secondary voltage is 27VAC. The builder hardwired document shows the double primaries but thanks for clarifying only one primary is needed. The capped primary performs as an autotransformer with input voltage also present on its leads.
Regards,
Huntersplace
Uhhh, isn't that backwards... the output voltage is proportional to the turns ratio. Series connected PRIMARY windings will cut the output voltage since the effective turns ratio goes down (the series connected windings look like one long winding with double the number of turns).
ReplyDeleteParallel the primary windings (or use just one winding) and the effective turns ratio will go up.
When connecting transformer windings in series or parallel you MUST get them phased properly. And you should always use both primary windings (series'd or paralleled( if you want the full rated power output of the transformer.
Uhhh, Anonymous, you are wrong.
ReplyDeleteIf you connect the two 110V windings in series you will be able to connect 220V on the primary. Your voltage doubled and so did your windings. If you look at the formula for the voltage of your secondary winding Vs = NsVp/Np and work Vs out with 1 x Primary voltage(Vp) and 1 X primary windings (Np) and then make it 2X primary voltage and 2 X primary windings, you'll see the secondary voltage stays the same. You will get 25V on both secondary windings of this transformer with 115V on one winding or 220V on two primary windings connected in series.
With a parallel connection on your primary or your secondary side your turn ratio DO NOT CHANGE. Two copper wires connected to the same point and turned together in the same direction is the same as one thicker copper wire. The only thing that will happen here is that current carrying capacity will double.
The transformer in question here is a 625 Watt transformer with two secondary windings. The two windings connected in parallel will be 25V at 625/25 = 25 Amp. One secondary winding will be 25V at 12.5 Amp.
THIS WELDER WORKS WITH A 12AMP TRANSFORMER, DO NOT CONNECT THE PRIMARY WINDINGS AND/OR THE SECONDARY WINDINGS ON THIS TRANSFORMER IN PARALLEL. YOU WILL BLOW THE Q4 MOSFET.
Electrons through a winding flows in a certain direction and the directions of the two windings connected has to be in the same direction or your transformer will burn out.
Happy New Year Fritz! Anything new happen with the pulse arc welder? I've tried running some patent searches on pulse arc welders to see if I could find some info that might help with determining the what frequency is used for the pulses as well as waveform, but there are numerous patents out there and it will take me a while to scan through them. I even ran a patent search on the Ph.D who founded Sunstone Engineering and he does have a patent, however it's not related to pulse arc welding. Is there another possible name/term for pulse arc welding that you can think of that I should try to run a search on? If we can find some patent numbers for the Orion or PUK welders that would be extremely helpful. I might have to find someone on one of the jewelry forums who has one that might be willing to check for the patent numbers on the actual welder.
ReplyDeleteFerdi
Hi Ferdi, Its a good idea, I never thought of that. I'm just looking for the waveform, voltage and frequency they use and I will put a circuit together. I have no other information on that at the moment though.
ReplyDeleteI stopped working on my pulse arc welder due to the holidays. I am kind of leaning away to add it to the current capacitor discharge welder and totally redesign the whole pulse arc welder. The reason is so that I can add more functions, save waveforms and much more.
Someone placed a comment a couple of days ago, asking about maybe making the welder with an arc start circuit and not using a solenoid. I didn't think much of it but kind of started to change my mind after thinking about it. I should be able to stop the high voltage circuit fast enough to prevent a shock. Sunstone has a new welder and I do believe it has an arc start.
All these designs take time and my budget is holding me back at the moment.
there is an arc start circuit in this project that may be of intrest?
ReplyDeletehttp://www3.telus.net/public/a5a26316/TIG_Welder.html
Hi Fritz,
ReplyDeleteFound an interesting article about MOSFETs, power switching and board layout. Every time I look at my three heat-sinks I cant help but to think about this device. Since you are between designs just some food for thought. The link is:
http://powerelectronics.com/power_semiconductors/power_mosfets/power-controller-symmetrical-layout-1107/
Hope you find it interesting,
Matt K.
Hi Fritz,
ReplyDeleteI would like to purchase your Spot Welding kit along with design details. Unfortunately no shipping is available to New Zealand. Could you please advise if its possible.
Thanks,
Jedy jedy.s@live.com
I've added New Zealand to the online store
ReplyDeletehey matt i plan to fold over the mosfets paralell to the board and use one big heat sink with fins from back to rear just to be different and also hope fully to aid in cooling and possibility conductivity if they are metal backed.
ReplyDeleteare the fets metal backed mine hav not turned up yet?
also how does he connect the drain and source pins to the aluiminum?
To professor_jonny indeed the 2907's have an exposed die... have not heard of any power switching FET's that dont... but then again I lead a somewhat sheltered life...do you have an example of one without an exposed die? Anyway, 'cool' idea with one big heat sink. I have been researching the idea of liquid cooling but am undecided as yet. It SEEMS fairly easy to make a liquid cooled aluminum block, probably overkill...and too must consider that pesky budget!
ReplyDeletethe drain and source pins to the aluminum? Not sure if you are referring to the article but I
thought it mentioned/showed the pins were bolted down. Do you think it would be better to weld them to the aluminum? I can think of one homemade spot welder that would be perfect for that job.... ;o)
MK
Where are you guys getting your foot switches?
ReplyDeleteMike
Here Mike http://www.amazon.com/Linemaster-T-91-SC3-Single-Circuit-Treadlite/dp/B002P4W5UC?&camp=212361&creative=383961&linkCode=waf&tag=h0cf4-20
ReplyDeleteThanks for the url Fritz. I ordered one today. I changed the load resistors from 20 ohms total to 10 ohms total. The liked the quicker discharging. So I tried 6.6, 3.3, and 1.65 ohms total. The discharge at 1.65 ohms total was very quick. The Q4 fet barely got warm even after repeated discharge cycling on 1.65 ohms. But the one thing that was different was that as the charge voltage was being increased, the voltage each time I stopped turning it up, would become very unstable. Q4 would rapid fire at low or high voltages. Is there a correlation between the discharge resistor bank and a narrow hysteresis of the increasing charge voltage?
ReplyDeleteMike
Mike, I have no idea why you are changing the discharge speed. When you do welds, you won't adjust your welder up and down all the time. You will set it on a voltage and make small adjustments until you find the correct one. You will not even notice a slow discharge.
ReplyDeleteTo answer your question. Yes there is a way to change the charging hysteresis, MAKE YOUR DISCHARGE RESISTORS BIGGER.
You talk about changing the discharge speed in the manual Fritz. That's why. Here's the quote "VOLTAGE SET POINT IS LOWERED AND THE 39 OHM 10WATT RESISTERS CAN BE REPLACED WITH 20 OHM 20WATT RESISTERS OR MORE RESISTERS CAN BE ADDED TO MAKE THE DISCHARGE FASTER."
ReplyDeleteSo I made it faster. I didn't know what the limit was so I found out empirically. Because I'm still figuring out the layout of the welder in the chassis, it's nice to be able to discharge the cap quickly so I can get it out of the way. The fet handles the extra load with ease. It looks like the hysteresis was the only downside.
Mike, we have already determine that the car capacitor that you use have a very high discharge current the higher the voltage gets. The processor checks and do an analog to digital conversion on the cap voltage at a specific time interval. This time interval is not always on the exact same time because it has to wait for certain processes to end first before checking the cap voltage again. Your high cap discharge + the low resistance that you have makes it overshoot the set voltage before the processor can check and stop the discharge. Now the voltage is below the set voltage and the processor starts to charge the cap again. That's why you get the erratic behavior. If you use computer grade capacitors your problem will be solved.
ReplyDeleteIn the manual for your thermostat at your house it says to turn up the heat when it is too cold, do you turn it up to 100 degrees?
No offense, I've been asking the guys not to unnecessary bug me and it seems like you are going to have an issue or are going to ask a question for every wire you are going to connect to your welder. Please use some common sense.
hi fritz,
ReplyDeletejust to note out that 1 of the parts in the bill of materials is marked oboslete and out of stock.
c3 and c4 of the control board and c3 of the power section VJ1206Y104KXAMC is an alternative code.
i have also noticed the BC847BLT1 transistor is labled q6 on the bom and q2 on the circuit board no major.
hi fritz q3 is missing from the bom i have here too IRF530
ReplyDeleteThanks for the info on the capacitors.. There are lots of replacements for those components and can be easily matched up with components with the same values.
ReplyDeleteBC847 is marked Q6 on the BOM and Q6 on the board, Q6 on the schematic and Q6 on the Block diagram....lol what are you smoking Jonny? :)))
In the manual on page 2 it says not to use Q3 Jonny
lol,
ReplyDeletei was out on the gas last night a pretzil party where you get free tasting of different spirits to try to sell you it.
now reading the manual i see that there are bits that are not required.
i just referenced the parts i have from the schematic and noticed there were some missing from the bill all sorted now.
How do I locate the "online store"?
ReplyDeleteEd F
ReplyDeleteHi Fritz
I would like to know if you are ordering more boards and if so should i pre pay for the board kit. I think this CD Welder is great and you have done a fantastic job on this welder and a lot of hard work.
I have one full set of boards left https://secure.digitalcontentcenter.com/shop/569822/products/
ReplyDeleteI will not be selling or ordering anymore boards after this set is sold
hi Fritz,
ReplyDeleteIm wondering on a source for industrial caps and aprox how much they cost you?
I have brought several audio caps from a local auction site (trademe.co.nz) and were well below what they were ment to be.
i even got a 12 farad cap bank thing and was less than 3 farad after testing!!!