My Son and I are building a project for the science fair. We need 300 vdc at 3amps max. We bought a Variac that will give us from 0 to 300 vac and were told to just run it thru a bridge rectifier and we would be good to go. Now that part has turned into a big project because neither of us have that much experience.
We have a simple diagram (that I can't seem to get to post) that I'll describe here. From the Variac we go to a CoreCom 5K1 filter - We're told that this will remove 'noise'. from that we go to a doide bridge rectifier that should be rated at at least 300 volts and 50 amps just to be safe. From that we go to three capacitors (C1-1000uF / C2=10uF / C3=920uF) wired in parallel and we're done. My questions are these:
1) I have found the CoreCom but cannot locate a diode bridge rectifier rated above 40 amps and the specs are confusing - forward voltage & amps and reverse voltage & amps - I assume I'm only concerned with forward ? Could you recommend a brand/part#
2) The end result is to hook a cathode and anode up that are submerged in a chemical solution. Does it matter what the resistance is here - or is it okay to turn this ON with no resistance or does it really matter?
3) Is there a reason I can't just have one big capacitor instead of three - and what should the uF value be.
4) Only the Variac itself has a fuse - shouldn't there be some type of additional fusing somewhere?
Thanks so much for any help you can provide.
If there is an easier way to get the Variac A/C into the desired output voltage and amperage please feel free to suggest.
Lonnie
We have a simple diagram (that I can't seem to get to post) that I'll describe here. From the Variac we go to a CoreCom 5K1 filter - We're told that this will remove 'noise'. from that we go to a doide bridge rectifier that should be rated at at least 300 volts and 50 amps just to be safe. From that we go to three capacitors (C1-1000uF / C2=10uF / C3=920uF) wired in parallel and we're done. My questions are these:
1) I have found the CoreCom but cannot locate a diode bridge rectifier rated above 40 amps and the specs are confusing - forward voltage & amps and reverse voltage & amps - I assume I'm only concerned with forward ? Could you recommend a brand/part#
2) The end result is to hook a cathode and anode up that are submerged in a chemical solution. Does it matter what the resistance is here - or is it okay to turn this ON with no resistance or does it really matter?
3) Is there a reason I can't just have one big capacitor instead of three - and what should the uF value be.
4) Only the Variac itself has a fuse - shouldn't there be some type of additional fusing somewhere?
Thanks so much for any help you can provide.
If there is an easier way to get the Variac A/C into the desired output voltage and amperage please feel free to suggest.
Lonnie