Regen Fire- 98VF/4 fun! Vector IGBT Regen notes and Q/ on the PEPI sensor .

Had our first little fire-drill event! As a thriller novel - The son came crashing into the room. "Something's burning" he shouted! Instantly he retreated back out the door he flew in from. Just as I clear the threshold into the Shop with my nose in the air, the the VF console pushes it's 'Regen overheat' and Alarm. Bang- Eyes to the top rear... It's like in slow motion for me even after 2 days. Sort of even funny now. I looked up to see the Regen resistors cage glowing that aggressive apocalyptic red glow of the toaster-oven on broil. You just don't forget that cage and that much red light! Now we know what's up. The Haas is suffering from regen-itis! Smoke is also pouring out the top with some pretty good flame. bang-zoom, I'm up the rear ladder already while the kid was grabbing the extinguisher. He has the hose in his hand about to yank the pin. I will also never forget the wildest look in his eyes which told me instantly he was milli-seconds from yelling "Duck" while blowing that Sh%t all over my restored VF. OMG moment... flashback for many here possibly; I recall the time we teenagers discovered how much sheer excitement and overwhelming mess you can make with a dry chemical FE in a room. right? you know you did it too.

OK Drama done. There is a serious part to this. What he did not know or realize yet is that I keep the big bag of Baking Soda on the bench for more than just my battery clean ups and mild cleaning grit... A small handful of the soda put out the on-fire thermal sensor instantly. Cutting the electric instantly stopped the current flowing to the regen pack. Now he knows. Whew!


I still cannot locate the correct thermal sensor equivalent. They are made by PEPI, were labeled 19+100F The Co is still around but has not returned my calls or emails yet. Something from this page I suspect Products - Portage Electric Products, Inc. If anyone knows a source for an direct replacement... all ears!

The IGBT's are IXGN 60N60 obsolete but thousands out there from sources. ebay and UT I just bought 4. $13 per.
60N60 IGBT Datasheet pdf - IGBT. Equivalent, Catalog

And the root cause, another lesson learned for me- Recommended replacement vs direct equivalent, When I asked a component supplier to 'spec' a substitute Vector drive regen IGBT for the obsolete one a few years back the OEM 'suggestion' for new designs was a 60amp unit. This is a 100amp device. Putting in replacement electronic parts should be carefully selected. I trusted someone else and but never verified it as a direct equivalent. The IGBT failed when under high-rpm braking. shorted to ground, which sends the current to the regen pack. Ta-da- fire.

Never a dull moment in the shop.

Just something on a catch-up eve.

Wanted to add a source/ equiv for the PePi sensor. could not get ahold of a single person there.
5pcs TB02 Miniature Thermal Protector 100degC Normally Close 15x5.4x2.4mm UL VDE | eBay Snap action type. (100C and snaps to open).
Works well enough. it's zero ohms, connected to the I/O board. Once hot enough, the short is an open switch, and the controller will pic it up. ensure it rests firmly in the folded metal plate inside where the PEPI unit was.

I also found another PEPI sensor on a VF/6 spindle motor we are rebiulding. It was tucked into the Spidle motor fin. Not sure of the temp but so others know. They come in NO and NC types and a bunch of temperature ranges. be sure to know if you need a creep or snap action type.

Well, lucky you do not have an earlier machine where the regen resistor is located below the servo boards which are below the three board computer stack.
I thought this was not very bright putting all that heat into the boards so I remounted it outside the cabinet on top, in a 4" duct with a PC fan below it. I replaced the tubular ceramic resistor with another but when this one goes out I will use the cook top element, far cheaper.