How did it do that

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ABB. Owner & well guy were a bit frustrated that I wanted the well pulled before we continued. We could have bypassed that feature but it failed our meg test with .3 meg @ 47volt. "Well it worked with the old starter" came up more than once. We were alll a lot happier when we found the dinged wire. 7.5 hp 480v 3ph.
 
ptonsparky said:
ABB. Owner & well guy were a bit frustrated that I wanted the well pulled before we continued. We could have bypassed that feature but it failed our meg test with .3 meg @ 47volt. "Well it worked with the old starter" came up more than once. We were alll a lot happier when we found the dinged wire. 7.5 hp 480v 3ph.
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Cool; it's always nice when the electrician turns out to know something nobody else would've suspected.
 
ptonsparky said:
Connected a VFD to submersible today and before I even got it programed it had tripped on a ground fault. Bad spot in the drop cable. Does the drive actually charge motor and conductors before a start call?
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Yes I believe they do. It helps to protect the drive's electronics. It is also why most drive mfg's warn not to disconnect or touch the output wiring for several minutes after powering down.

That drive saved a future breakdown call.
 
The ABB drives have a Shorted Load protection scheme that puts an initial 40V pulse to each phase circuit right before going full tilt boogie. It looks for a current response beyond what it expects to see (no data on the value they look for). But it's supposed to only do that when you give it a Start command. Are you sure there was no preexisting programming that would have it starting as soon as you powered it up? Often times, people use what is called a "sleep" function that sets the speed to Zero if the analog signal is below a threshold. The drive is technically "On" even though it has no effective output. But in that mode, it would do the pulse check of the load circuit when initially powered up.
 
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