Sunday, October 25, 2009
I have added the over voltage protection circuit and updated the Schematic and 3D board below. I ran the Capacitor charging circuit through some heavy testing and it performed better and faster than all calculations. I designed this PCB in such a way that I can easily add a new feature or change an existing one by just changing the programming on the microprocessor. I have some more tests to do and painstakingly go through every component and hole sizes to make sure everything is perfect before ordering some professionally made boards.
Tuesday, October 13, 2009
I've spent a week reading through data sheets trying to find a suitable mosfet driver for this welder. The LTC driver that I selected is kind of an overkill but it works very good. I also changed the code to the Micro in such a way that when the capacitor is completely discharged or at a low voltage it will limit the current to protect the Mosfet and the transformer. I am busy designing an over voltage protection that will turn the mosfet off if the voltage goes over 20V and also a separate over voltage protection for the capacitor if the mosfet fails. The charging speed is fast enough for a dual pulse so I'm kind of throwing the contactor idea away at this moment(still have all the files) and working on making this a solid state welder that will be much cheaper than the $5000 price tag. Hang in there and don't build it yet until I give the go ahead.