We have a community well here serving several houses. The whole thing is
pretty fancy. The pump is a 3 phase unit. There is no 3 phase in the
subdivision. But, the controller 'makes' 3 phase and supplies the pump
with 40 to 70 Hz depending on the demand. As there are now few houses on
that well, it's probably running at the 40Hz frequency. The controller
is a Franklin Electric SubDrive 300. I called Franklin Electric and they
wouldn't provide a schematic as it is a "throw-away" device. Excuse me,
it's a $2500 throw-away device! BTW, they won't fix them either ... only
sell you a replacement. Kind of reminds me of Behringer audio equipment.
Anyway, the unit has already been replaced and I have the old unit. I
would like to fix it for a future breakdown. Has anyone dealt with these
units? Any tips would be greatly appreciated. I know that these type of
circuits, basically akin to a switching power supply, can be tricky to
Looked at the PFD on the unit; that is pretty fancy for the purpose,
indeed. I'd wager you'd not really notice the difference if simply
replaced it with a conventional system going forward.
I note there are some diagnostics; do you have any indication of what
the failure code(s) were, if any, when that unit was removed? Be a
A simple replacement would be nice, however, the pump motor itself is 3
phase and there is only single phase available. So the pump would have
to be replaced. Also, the unit was pulled by a local well drilling
company, so I don't know what the error codes might have been. They only
know to replace and junk the old unit. Other than removing the top, I
haven't looked inside yet.
Or with just a conventional converter...
But, unless this is a really large well, swapping out the pump the next
time instead of the controller may be no more expensive at the time and
be less maintenance/expense going forward by far...
Just the thought that strikes me having been on a well for almost entire
life I don't see there's any difference between a conventional pressure
tank system and "city water supply" to be worth such an additional
complication/expense as that controller.
Just how big a well and water system is this, anyway?
You haven't indicated the failure mode. Chances are, one of the FETs in
the output drive is dead (you'd need a 'scope or DMM to start). If it
is just behaving "really weird" (for sufficient values of "weird"),
it could be something as simple as failed electrolytics.
What is the environment like where the controller is normally located?
Can you smell any "burnt" odor? Is the controller potted?
On Saturday, September 5, 2015 at 12:49:54 PM UTC-4, Don Y wrote:
And for the replacement one, I hope there is good, properly installed
surge protection. Lightning surges are a frequent source of failures
on that type of eqpt. A $100 surge protector could save spending big
That sounds like a good suggestion, moving forward. The unit is located,
not at the top of a mountain, but maybe 85% of the way up, so it and its
associated power lines, could be more vulnerable to lightning strikes.
The lines themselves, are underground, but the transformers, etc., of
course, are above ground. Presently there are no houses in that part of
the subdivision, however, the power infrastructure is there.
I've seen the aftermath of lightning hitting the ground. It had
bored a hole in the ground to an underground wire that was bad. The wire
about 30" deep. There were maybe fifteen or twenty corn plants
hit that were yellow. The rest of the field was green.
I thought the part about corn plants being burned was just an old
tale. It wasn't.
Using Opera's mail client: http://www.opera.com/mail/
Lightning seldom actually hits the stuff it blows up. You are
protecting from transients on the power line and it is usually a
difference between the ground at the panel and the ground at the
equipment that kills you. Make very sure that your lightning protector
is connected to the well casing or, if it is plastic, drive a rod or
two right there.
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