lol, I totally forgot about that thing. Winter project my ass 🤣
I appreciate your safety advice. You’re right, it’s better to be safe than sorry! Rest assured, I’ve already had a bunch of high voltage (and high power) equipment on my workbench.…

Bulk recapping equipment can be kinda therapeutic. Put on some good music and let it flow. Just don’t zone out too much or the new caps may go in backwards…

Excellent! What kind of string are you using? Mine keeps stretching and the motor starts to slip, so I have to tighten it now and again.

These caps came out of an Allen Bradley 1336 drive, these things use SCRs for bus rectifiers. Two failed and shorted, essentially feeding AC into the caps.

Thanks for the explanation, the layout makes more sense now.

This is a similar style IGBT block I pulled out of an elevator VFD the other day. It’s slightly overdone.

Wait a minute, they were running high voltage, deflection and video signal through a 25ft cable? That must’ve been great for signal integrity…

What apparatus are we looking at here?

I know, right? This thing is overdone for what it does but at the same time lacking in features. I mean, custom machined case, metal parts and PCB but all it can do is beep. It’s as useless as modern art.

You know the drill 😂 Occasionally it’s easier to kinda “chisel” the pins off. Some IGBT modules leave a small gap between the case and the PCB, a small flat blade screw driver fits in there. A light whack with a small hammer does the rest…

Digging through my stash today, I found this IGBT module. It seems pretty close to yours, at least as far as the pins configuration. This is part number 7MBR50SB120-50, made by Fuji Electric. 1200V, 50A rated.

Once most of the solder is out of the hole, I carefully wiggle the pin with needle nose pliers. You kinda get a feel for it after doing it over and over…

Actually, I use a regular soldering iron (ca. 50W, ~800F) with a chunky, flat tip and a solder sucker. Standard 60/40 solder does the trick, but it’s good to have some flux paste handy. Some pins are more stubborn than others, I put the solder sucker to those 2 or 3 times.

Yeah, that happens a lot. It’s impressive that such little devices can handle high voltage and current. On the other hand, they are quite delicate and it doesn’t take much to make them explode.

I can only speculate as to what happened. My guess is that they aged badly, dried out, turned into resistors and got hot. The insulation failed and current started to leak into the metal cans. I didn’t notice the damage until after they went bang. That made the whole repair shop happy 😆

Pretty sure I’ve seen this pin configuration before, maybe in some Allen Bradley VFDs (PowerFlex series). I’ll take a closer look next time one of those comes across my workbench.

Looks very familiar. I work on motor drives (mostly servo) all the time, usually I see the inside of IGBT modules only after they blew up.

Perhaps 100 to 200 mW depending on cooling/ventilation. Usually I like to play it safe and don’t max out component ratings, at least in final designs.