Re: Big motors
When I was an apprentice, I spent some time in Quality Control Department of an automotive electrical manufacturer. One day, when we were doing routine tests of car speedometer head units, every single one was out of calibration. This was a "Line Stop" situation, and I was despatched, armed with a trolley of test gear, to find out why the line testing equipment was wrong. The Line Foreman was very indignant, and said that there couldn't be anything wrong with their setup, it had been calibrated against the electrical mains supply just that morning. I connected up all my equipment, and the mains frequency was spot on, but their testing machine didn't synchronise with it. I asked what time they had last checked it, and it coincided exactly with the spark plug machine being started. This machine was only run for about an hour every day, because the rest of the spark plug line couldn't keep up with it. I asked them to start the machine again, just for a few seconds, and the mains frequency went down to 49.8 Hz while the enormous motor was spinning up, returning to 50 Hz once it was up to speed. Turned the machine off and recalibrated the speedometer tester, no more out-of-calibration speedos that day. Made sure that the same thing could not happen again by scheduling recalibration for the end of the shift, ready for the following morning's work shift.
Had a similar problem with the fuel gauge line, 33% scrap rate on one particular subassembly, but as the output from all three machines went into a single hopper, couldn't trace the source that way. Then, one of the operators was off sick for a day, and only <1% scrap rate that day, so she was reassigned to another part of the production line, and the problem mysteriously disappeared.
Biting the hand that feeds IT
