Don't understand the full intricacies of it but basically yes, it sends a set number of pulses through the coil and measures the time taken for each coil turn.
Col wrote:
The surge also produces a wave form and if there are 'shorted turns' then the wave form will spike and possibly oscillate from side to side. Based on this principle if two phases are in contact, (i.e. shorted then the wave form should show one of or both of these symptoms. For some inexpilicable reason none of the testers used showed this. This is what is so confusing to everyone as we then tested a motor known to have this fault and it showed up as expected.
One thing which is puzzling me is when we do a DC machine we do whats called a 'single phase' test. In this we only use leads 1 and 2 for the surge with the feed set to position 1. After we get our 'datum' wave instead of switching to position 2 we simply swap leads 1 and 2 (coil end),over and repeat the test. If the coil is sound we will get a perfect overlay. The techies machine does this automatically instead of manually so we should have got the same result. However, on his machine there was a 20% difference when we tested each phase separately. If I get chance on Monday, (I'm on a site induction first thing), I'm going to use our machine to do the same test and see what results I get.
Crikey, this is turning into an episode and a half this! I actually thought I'd get very little response to the original post! Thank you!
Col, Just reading the preview and I think I understand now what you mean by coil to coil and coil to earth. The 'surge' test is supposed to test coil to coil, the Hi Pot does coil(s) to earth.
Col wrote:
By the highlighted section I take it you are referring to 'meggering' the coils to earth, if so, then that is part of the 'surge' test. The Hi-Pot test is looking for earth leakage over a set period of time, i.e. 1 minute.to be fair, I would have thought that basic end to end continuity and coil to coil and coil to easth IR testing would be the first thing you did prior to the fancy "ping" testing
The surge also produces a wave form and if there are 'shorted turns' then the wave form will spike and possibly oscillate from side to side. Based on this principle if two phases are in contact, (i.e. shorted then the wave form should show one of or both of these symptoms. For some inexpilicable reason none of the testers used showed this. This is what is so confusing to everyone as we then tested a motor known to have this fault and it showed up as expected.
One thing which is puzzling me is when we do a DC machine we do whats called a 'single phase' test. In this we only use leads 1 and 2 for the surge with the feed set to position 1. After we get our 'datum' wave instead of switching to position 2 we simply swap leads 1 and 2 (coil end),over and repeat the test. If the coil is sound we will get a perfect overlay. The techies machine does this automatically instead of manually so we should have got the same result. However, on his machine there was a 20% difference when we tested each phase separately. If I get chance on Monday, (I'm on a site induction first thing), I'm going to use our machine to do the same test and see what results I get.
Crikey, this is turning into an episode and a half this! I actually thought I'd get very little response to the original post! Thank you!
Col, Just reading the preview and I think I understand now what you mean by coil to coil and coil to earth. The 'surge' test is supposed to test coil to coil, the Hi Pot does coil(s) to earth.