I have now run a few tests with the TKED1 from SKF.
First impression: Little nice device that fits in your shirt poccket. Easy to handle. Batteries were almost DOA. Current consuption in OFF state is very low. But noticed that it can easily be turned on by EMI. Could be that it has been doing its thing in the box without anyone knowing it.
Second impression: Antenna breaks far too easily. SKF has obviously realized that. A spare antenna was delivered with the TKED1. But what when that antenna also breaks? Seems to be a question of a few seconds looking somewhere else. Or climbing a machine with the device in your shirt pocket. I guess that it has to be kept in the carrying case if it shall live more than a few days.
Test on bearing in test fixture: Works quite well. Indicates breakdown at levels around 5 V across bearing and antenna at about 100 mm distance. Well done!
Test on bearing in motor: Very difficult. PWM seems to override bearing signals. It will probably work on motors with a very good filter between VFD and motor and/or motor mounted on solid ground-plane.
A little quirk in the software: Rolls over from 99999 to zero and starts over again. That means that a measurement that should read 100123 reads 123. And that is something entirely different. The device was probably not meant to show numbers that high. But it does that easily when kept near a VFD drive/motor. Not a big problem. But could easily have been avoided if tested thoroughly IRL.
I don't know. It can be used to detect bearing EDM in DOL motors. But that is not where EDM is a problem. I will do some tests in a steel mill next week. They may have better grounds than I have in the lab and that will probably do the TKED1 better justice. But, OTOH, HVAC installations are very much like my lab installation. So, some hesitation as to its usefulness there.
Stay tuned!
Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
