NO, you will blow the transistors as they will turn on together and short out the supply.

You need to cross connect the Bases so that opposite transistors conduct, So top Left and Bottom Right bases , top Right and bottom Left.

just changed the transistors now with 60n60 1:1, but unfortunately it blown off
What could be the problem?

Thanks

just changed the transistors now with 60n60 1:1, but unfortunately it blown off
What could be the problem?

Top MOSFETs and bottom MOSFETs must never be on at the same time.
There must be a short time when no MOSFETs are on.
Bottom MOSFETs are driven by a driver sitting on (-).
Top MOSFETs is driven by a signal that is not related to (-) but by (AC)
View attachment 221162

just changed the transistors now with 60n60 1:1, but unfortunately it blown off
What could be the problem?

 

just changed the transistors now with 60n60 1:1, but unfortunately it blown off
What could be the problem?

So you are trying to repair a commercial welder,correct? Do you have the original transistor part numbers?

 

Connect it like this,, put the coil across the collectors..

View attachment 221272

but connecting the gates like that will blow up the IGBTs.
Top left transistor will have 330V on its gate. Bottom right transistor has its source at 0V, so with 330V on its gate it won't last long.

No real advantage for this method (assuming the correct gate drivers) or the original. Both use four transistors. The original (half bridge) needs a capacitor in series with the winding, and operates at half the voltage and twice the current. This circuit (full bridge) operates with a higher voltage/lower current winding, requires no series capacitor but needs twice as many gate drivers.

UNLESS - it is a resonant power supply, in which case it DOES need the series capacitor.

 

If he is repairing a welder, not making one from scratch, he may be threw out the insulators for the IGBT's. Most of the welders I've seen the insides of have all of the transistors mounted on one big heat sink, but then they need to have insulators too. Someone with no experience may think they aren't needed and leave them out.

 

If he is repairing a welder, not making one from scratch, he may be threw out the insulators for the IGBT's. Most of the welders I've seen the insides of have all of the transistors mounted on one big heat sink, but then they need to have insulators too. Someone with no experience may think they aren't needed and leave them out.

Please what type of insulator
this is the circuit of the project

but connecting the gates like that will blow up the IGBTs.
Top left transistor will have 330V on its gate. Bottom right transistor has its source at 0V, so with 330V on its gate it won't last long.

No real advantage for this method (assuming the correct gate drivers) or the original. Both use four transistors. The original (half bridge) needs a capacitor in series with the winding, and operates at half the voltage and twice the current. This circuit (full bridge) operates with a higher voltage/lower current winding, requires no series capacitor but needs twice as many gate drivers.

UNLESS - it is a resonant power supply, in which case it DOES need the series capacitor.

but connecting the gates like that will blow up the IGBTs.
Top left transistor will have 330V on its gate. Bottom right transistor has its source at 0V, so with 330V on its gate it won't last long.

No real advantage for this method (assuming the correct gate drivers) or the original. Both use four transistors. The original (half bridge) needs a capacitor in series with the winding, and operates at half the voltage and twice the current. This circuit (full bridge) operates with a higher voltage/lower current winding, requires no series capacitor but needs twice as many gate drivers.

UNLESS - it is a resonant power supply, in which case it DOES need the series capacitor.

 

Please what type of insulator

If the transistors you are going to use have a plastic back (the side which fits against the heatsink) then no insulator is needed.
If they have a metal back, this is often connected to the drain and would need to be insulated from the heatsink.

 

If the transistors you are going to use have a plastic back (the side which fits against the heatsink) then no insulator is needed.
If they have a metal back, this is often connected to the drain and would need to be insulated from the heatsink.

what of this, the bottom?

 

Have you posted the brand and model of welder? I can't remember seeing it if you did. From one of your drawings it says 100amps, but several times you say you want to get 200amps out of the welder. You do understand the IGBTs will have no influence on the amperage out put of your welder don't you? The amperage output is dependent on the transformer in the welder, not any switching device in it.

 

Please what type of insulator

 

I see you're trying to add extra transistors to make it work better, these transistors need insulation tabs as shown to isolate the Collector from the heatsink.

There are MOSFETs in a SOT 227 package.

 

There are MOSFETs in a SOT 227 package.

IGBT's are also available in that package. Not heat sink insulator needed, That, SOT 227 package is what most industrial welders and plasma cutters use.

But still don't think he can double his output by just changing the switches/transistors.

 

Have you posted the brand and model of welder? I can't remember seeing it if you did. From one of your drawings it says 100amps, but several times you say you want to get 200amps out of the welder. You do understand the IGBTs will have no influence on the amperage out put of your welder don't you? The amperage output is dependent on the transformer in the welder, not any switching device in it.

IGBT's are also available in that package. Not heat sink insulator needed, That, SOT 227 package is what most industrial welders and plasma cutters use.

But still don't think he can double his output by just changing the switches/transistors.

I wasn't trying to double the output, the former 50T65 has burnt off, but I can only find 60n60 to replace it, now that I did the 60n60 has burnt off again

 

IGBT's are also available in that package. Not heat sink insulator needed, That, SOT 227 package is what most industrial welders and plasma cutters use.

But still don't think he can double his output by just changing the switches/transistors.

Does insulator really needed in this ?

 

Does insulator really needed in this ?

Are you asking about the SOT-227? Or the T-247?

SOT-227. The metal mounting base is insulated from all of the internal parts of the transistor. Needs no extra insulator but does need thermal past between the base mount and the heatsink.

T-247. The flat metal base of the transistor is a "live" part of the transistor. It needs a pad/insulator, but not the insulator bushing that comes in a insulator kit. The mounting hole in that package has plastic surrounding it. But you also need thermal paste between the transistor and pad plus between pad and heatsink.

But you still haven't answered my question. Are you expecting by just changing to a higher rated transistor to get a higher welding amperage? It won't happen. The transistors have nothing in them that will make any magic amperage, none.

 

View attachment 221156

You can still buy these transistors 60t65pes from AliExpress.

Have a look at this site for repairs.

https://jestineyong.com/shorted-igbt-60t65pes/

 

You can still buy these transistors 60t65pes from AliExpress.

Have a look at this site for repairs.

https://jestineyong.com/shorted-igbt-60t65pes/

Thanks

 

Are you asking about the SOT-227? Or the T-247?

SOT-227. The metal mounting base is insulated from all of the internal parts of the transistor. Needs no extra insulator but does need thermal past between the base mount and the heatsink.

T-247. The flat metal base of the transistor is a "live" part of the transistor. It needs a pad/insulator, but not the insulator bushing that comes in a insulator kit. The mounting hole in that package has plastic surrounding it. But you also need thermal paste between the transistor and pad plus between pad and heatsink.

But you still haven't answered my question. Are you expecting by just changing to a higher rated transistor to get a higher welding amperage? It won't happen. The transistors have nothing in them that will make any magic amperage, none.

No, I was just trying to find the good and equivalent transistors that will suit the work

 

Are you asking about the SOT-227? Or the T-247?

SOT-227. The metal mounting base is insulated from all of the internal parts of the transistor. Needs no extra insulator but does need thermal past between the base mount and the heatsink.

T-247. The flat metal base of the transistor is a "live" part of the transistor. It needs a pad/insulator, but not the insulator bushing that comes in a insulator kit. The mounting hole in that package has plastic surrounding it. But you also need thermal paste between the transistor and pad plus between pad and heatsink.

But you still haven't answered my question. Are you expecting by just changing to a higher rated transistor to get a higher welding amperage? It won't happen. The transistors have nothing in them that will make any magic amperage, none.

I can't get thermal paste or pad/insulator in my area is there any alternative please ?

 

I can't get thermal paste or pad/insulator in my area is there any alternative please ?

No. Can you get them from a different area - ebay, aliexpress, etc.

 

No. Can you get them from a different area - ebay, aliexpress, etc.

ok thanks