1. Home
  2. Electronics Design
  3. Confused about SCR ratings in three phase bridges

Confused about SCR ratings in three phase bridges

I am very confused about ratings of SCRs (silicon controlled rectifiers) in three phase bridges.

Let's say that I have this rectifier:

formatting link

It says that its rating is 116 A at 85 degrees Celsius.

Does this mean that a three phase rectifier bridge, composed of three such SCRs, can produce a current of 116*3 = 348 amps?

Even if the RMS current of the sum of the three currents is going to be a little bit less, due to them being out of phase, am I correct that such a bridge would still be able to produce 300+ amps?

This is for a welder that I am redoing. As an alternative to these, I have three bigger SCRs with 180A ratings. So I could use bigger ones.

I would like the rectifier part to be capable of producing 300 amps.

thanks

Reply to
Ignoramus11316
Loading thread data ...

If you look at fig6 on your data sheet It tells you the current rating and what heatsinks you need. 300A is around the maximum for these devices.

Reply to
cbarn24050

Thanks, yes, the answer was right there. I think that I will use bigger SCRs, just in case, and limit current to 200A, for now. I may revise the current limit later.

i
Reply to
Ignoramus11316

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.