Flux-Vector Variable Speed Motor
Flux-Vector Variable Speed Motor
(OP)
It has been 34 years since I took my only Sparks and Magic course. I just came across a pump for Oil & Gas wells with a Flux-Vector Variable Speed Motor which the pump write-up says can stroke 25 times per minute (dead stop to moving in the other direction 50 times per minute) without a problem.
The motor is driving a pinion gear that rides in a rack attached to a downhole pump. On the upstroke the motor is lifting a bunch of weight (thousands of feet of steel and a bunch of water. On the downstroke it is trying to control the rate that the rods are falling. Every direction change, the motor has to stop and then start under load. This sounds really difficult to me.
Can anyone explain this Flux-Vector motor (if that is a real term and not just a made-up marketing thing) and give me an idea if starting under load 50 times per minute times 5 years is even possible. It is a fairly new pump that seems to be working well, but I'm trying to get my head around possible life expectancy.
Thanks for your help.
David
The motor is driving a pinion gear that rides in a rack attached to a downhole pump. On the upstroke the motor is lifting a bunch of weight (thousands of feet of steel and a bunch of water. On the downstroke it is trying to control the rate that the rods are falling. Every direction change, the motor has to stop and then start under load. This sounds really difficult to me.
Can anyone explain this Flux-Vector motor (if that is a real term and not just a made-up marketing thing) and give me an idea if starting under load 50 times per minute times 5 years is even possible. It is a fairly new pump that seems to be working well, but I'm trying to get my head around possible life expectancy.
Thanks for your help.
David





RE: Flux-Vector Variable Speed Motor
This kind of technology is fairly mature now, if it's a reputable company with a history of success in this kind of application, it's likely fine.
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
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RE: Flux-Vector Variable Speed Motor
Thanks for the information. The company has been around for a while so it sounds like this is more reasonable that I expected.
David
RE: Flux-Vector Variable Speed Motor
As Jeff says: Go for it!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Flux-Vector Variable Speed Motor
David
RE: Flux-Vector Variable Speed Motor
RE: Flux-Vector Variable Speed Motor
Between rod stretch, seal leakage, valve leakage, and gas in the pump; energy effeciency has never been a real driver of rod pump driver selection. Mostly we calculate volume lifted over the distance lifted and come up with (say) 5 hp, then we install a 15 hp driver to make sure we have enough. Folks that try to get too close to the edge of the envelope find that failure to grease a bearing pushes them over max hp (or some other seemingly trivial screw up), most of us just put in a huge safety factor and accept the inefficiencies of part-load operation.
David
RE: Flux-Vector Variable Speed Motor
RE: Flux-Vector Variable Speed Motor
You guys are giving me a long list of great questions to take to the manufacturer. Thanks a lot.
David
RE: Flux-Vector Variable Speed Motor
RE: Flux-Vector Variable Speed Motor
David
RE: Flux-Vector Variable Speed Motor
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Flux-Vector Variable Speed Motor
David
RE: Flux-Vector Variable Speed Motor
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Flux-Vector Variable Speed Motor
Maybe you should consider a really large motor running just a flywheel. This would be low maintenance, reliable kinetic storage. Then the drives could regenerate and the energy would have somewhere to be stored for return to doing useful work. Much more useful than heating pond water!
Keith Cress
kcress - http://www.flaminsystems.com
RE: Flux-Vector Variable Speed Motor
David
RE: Flux-Vector Variable Speed Motor
Keith Cress
kcress - http://www.flaminsystems.com
RE: Flux-Vector Variable Speed Motor
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Flux-Vector Variable Speed Motor
We are really at the brainstorming phase of project development at this point. The pump manufacturer may say that the drive already has the means to store/reuse the breaking power. I should find out next week.
David
RE: Flux-Vector Variable Speed Motor
A single stand alone drive cannot store energy (short of a very massive battery system). But if you have multiple drives, you can set up what is called a "Common DC Bus" arrangement and have them all tap off of and regenerate back into it. With a decent coordination system, you could have one regenerating while another is motoring, that would SIGNIFICANTLY reduce the fuel consumption on the generator. But the drives have to all be in the same cabinet for that to work.
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Flux-Vector Variable Speed Motor
RE: Flux-Vector Variable Speed Motor
David
RE: Flux-Vector Variable Speed Motor
David
RE: Flux-Vector Variable Speed Motor
RE: Flux-Vector Variable Speed Motor
The speed variation will actually be less because the downward part of the cycle doesn't affect the genset. The VFD must, of course, be able to run off the resulting varying grid. If those people have done this for a couple of years, or more, they should know how to handle it.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Flux-Vector Variable Speed Motor
I visited one of the pumps in operation this week and it was on a feeder line with two homes and the homeowners weren't complaining (and these people WOULD complain, they bitch about everything else that the oil company does).
David
RE: Flux-Vector Variable Speed Motor
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies