Main Breaker Pictures

Has anyone opened the main breaker and taken a picture of the innards? I have a need for a picture today. Thanks in advance.

This good?

That is good but I think there is one part that is missing or at least I can’t see it in this picture. Thanks.

That looks complete to me

I am having a discussion with the manufacturer and can’t get into our shop for a while. There is a failure mode that results from a manufacturing defect. The defect is a rare occurrence that results from parts misalignment during a spot weld. I don’t see the part I remember in this photo.

Hi Al
Sorry this is likely later than you needed. I’ve uploaded a photo (awaiting approval) of a breaker we opened a couple of months ago. It was new, but opened intermittently on the robot. It looks fine internally with tight electrical contact so I’m unsure of root cause. I’ll link picture when it is approved, or you can PM me and I’ll send direct.
If there is a specific area you need a picture of let me know.

I can see it CD Media. I think that the part is under or on the other side of the part with printing on it. When you thought it had a problem did tapping on the red button make it worse? That is the failure mode we have seen. Did you notice if the contacts were mating properly? Do you still have the breaker?

To be sure everyone understands, this a very rare occurrence. I may see or hear about only one or two a year, tops.

Just for reference, here is the picture mentioned above.

I would say that at the time, tapping the breaker made it worse which made it untrustworthy. Would not say that it was the open button but it may have been. The breaker at the time was horizontal (facing up) and solidly attached to our protobot’s 1/8" holey aluminum belly pan. We though initially it was a loose stud electrical terminal contact. Once it was apart, I slid a piece of paper between the contacts and it was gripped fairly well, however it came out with a very, very small amount of 0.5 mm wide grey streaking from the top contact and a wider (0.5 cm), darker streak from the bottom contact, indicating to me that the contacts were not absolutely clean.
I just put it back together (with bolts replacing the rivets) and when electrically closed the red button is loose (it looks like there is about 1 mm of travel before it contacts the rubber gasket). It shows about 0 ohms on a cheap DVM (accounting for lead resistance). I bumped the breaker a lot and it stayed closed, but what seemed to me to be a light touch on the open button caused it to open then close then when the force was removed. The kitchen scale tells me it takes about 400 grams of push to break contact, so roughly 14 ounces (it takes about 1300 grams, 2.8 pounds to start to move the lever out). Do not have another handy to compare it to.
I do still have it. Let me know if you want it sent somewhere, or brought to IRI.
Thanks to Phil for posting the link.

I will let the Bussman guys know you have it. If they want it for evaluation I will let you know. Otherwise, can you bring it to IRI? We can discuss it then.

Sure thing!