I'll find any excuse to get my hands, and usually my shirts, dirty in the workshops. We had a 250kW AC compressor motor in from a customer who has been having problems with motor failures.

Yes, the windings have blown. So my guys and I got stuck in to see where and why the windings have failed. So I grabbed a glass-taped pry bar and got to work. It's a bit like peeling back the layers of an onion until you get to what you want to see. I must admit this was a pretty terrible rewind (not one of ours), but that's a story for another day.

I did have to place a bit of the old phase insulation behind the blow area to show it more clearly on the last picture. However, you might just be able to see where the failure happened. On the first turn, a blow between the first turn conductors and the second turn, breaching the sleeving.

Ever heard of the term 'reflected wave voltage spikes?' Well our customer soon did. What's more, we discussed how we can stop this happening again and solve a long-term problem they'd been having.

It's this forensic engineering that I love, it has a direct impact on reliability when you can do something about it too.