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Re: [PSUBS-MAILIST] AC induction well motors
Hello Pete, You are right. This type of motors are used as "pressure compensated submersible motors" from companies like Franklin and others, but when they sell then to such customers the price is many times higher then when they sell them in hundreds to well pumps.
The shape of the motor serves two purposes; small motor diameter will fit into smaller well diameter, (cost of drilling)
The fluid internally is usually a thin mineral oil or glycole, (anti-frost ). By keeping the diameter small the periferal speed of the fluid and thereby the power loss is minimised. To maintain required power with small diameter the lenght must be increased.
I'am working on a such design to my project and will use an electronic, DC to 3 phase AC converter,(about same complexity as a brushless DC drive unit), but the motors can be keept standard.
I would try to get hand on as many good 2-5 HP units as possible.
Regards limseth@online.no
----- Original Message -----
From: "Pete suds" <subs_n_suds@hotmail.com>
To: <Personal_Submersibles@psubs.org>
Sent: Tuesday, July 23, 2002 1:07 AM
Subject: [PSUBS-MAILIST] AC induction well motors
> Hi guys, I've got a question/oportunity? My neighbor owns a water well
> drilling and service business. I was in his shop and noticed a stack (40) of
> used deep well motors (220VAC induction, 2HP/5HP/7HP/10HP and 15 HP). I
> asked him about them and he said half of them work, but when he pulls a well
> pump, he doesn't put the old motor back if it is more than 5 years old. He
> gives them to the junk man about once a year.
> He gave me one, and I took it apart (psubber). The seals only keep out
> particles, but allow water into the area between the field coils and
> armature. Theoretically, they could operate at any depth. The field coils
> are encased in epoxy (it appears), so they don't get wet. The armature is
> free to rotate in the water (a few milliliters) and appears to be made of
> aluminum and a coating of ?. The field coils are encased in a stainless
> steel can. I took one apart, and some clear water ran out. I put it back
> together and hooked it up to 120VAC. It operated, but obviously at
> undervoltage.
> Why couldn't a permanent magnet, brushless, DC motor be constructed the same
> way?
> Have rare earth magnets on the armature, and have the field windings encased
> in epoxy. I noticed there were some O-ring seals on the inductive motor to
> keep out sand and other particles. Obviously, being a DC brushless, control
> circuitly would be necessary.
> This would eliminate most all the problems with submersible DC motors.
> Am I reinventing the wheel here? Does this motor already exist, or is this
> worth investigating,
> Suds
>
>
>
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