Electronics > Projects, Designs, and Technical Stuff
Max pressure for electronics (deepwater, downhole)?
sicco:
--- Quote from: voltsandjolts on August 14, 2022, 08:25:03 am ---
--- Quote from: sicco on August 13, 2022, 09:48:07 pm ---The 3 Hall sensors inside the Maxon BLDC oil&gas, geothermal well ‘catalog’ assembly somehow can survive high pressure exposures.
--- End quote ---
I think you have misunderstood the Maxon specification. Their motors may be used submerged in oil, but they don't rate their motors to operate directly in oil at 15kpsi. They operate in high temperature and high pressure environments but within a sealed pressure housing which isolates them from the wellbore pressure. Design, test, manufacture and full qualification of a dowhole electro-hydraulic power unit is an expensive business, but it has been done of course. A pressure balanced HPU design needs to isolate the motor from the wellbore pressure.
--- End quote ---
Double checked with Maxon. They say "We do have customers who use these motors over years at 150°C and pressures up to 20’000 PSI at the same time."
So that's what their motors operate at (immersed in clean hydraulic oil, oil that also gets pressured up to downhole wellbore pressures of the same magnitude - pressurised via a seal that communicates P).
sicco:
Plus an encouraging note from MPS: "The MAQ473 would be a better choice. About the pressure, according to some experimental data we have: at 100 bar there’s no effect on sensor behaviour, while at 1000 bar the sensor can still operate, but there may be a drift on the output in the range of 1°. "
That's the best response I got so far! So I ordered some samples...
tszaboo:
--- Quote from: mag_therm on August 13, 2022, 07:55:43 pm ---This is another case I have seen before on eevblog of designers reluctant to contact vendor applications engineers with queries on products they intend to use.
Why is that?
In my day and up to retirement recently they were #1 contact
There are lots of electronic systems down boreholes and undersea, and of course it has to be done with the right parts and methods.
--- End quote ---
Because they often times are not getting replies to their questions.
Because industrial systems are made in the quantity of hundreds, maybe thousands and not millions (like consumer), we are second class engineers when it comes to support.
I heard TI closing down my support, telling me "to just ask it on their E2E forum". Or not getting back a reply when I asked for a quote.
And the world would literally fall apart if it wasn't for us. This is downhole drilling. Imagine not getting your parts and support, and running out of oil.
mag_therm:
--- Quote from: tszaboo on August 24, 2022, 03:00:38 pm ---
--- Quote from: mag_therm on August 13, 2022, 07:55:43 pm ---This is another case I have seen before on eevblog of designers reluctant to contact vendor applications engineers with queries on products they intend to use.
Why is that?
In my day and up to retirement recently they were #1 contact
There are lots of electronic systems down boreholes and undersea, and of course it has to be done with the right parts and methods.
--- End quote ---
Because they often times are not getting replies to their questions.
Because industrial systems are made in the quantity of hundreds, maybe thousands and not millions (like consumer), we are second class engineers when it comes to support.
I heard TI closing down my support, telling me "to just ask it on their E2E forum". Or not getting back a reply when I asked for a quote.
And the world would literally fall apart if it wasn't for us. This is downhole drilling. Imagine not getting your parts and support, and running out of oil.
--- End quote ---
Yes, I was in high power electronics. While the control electronics were usually no problem with ordinary industrial grade, the power side was specialised often with vendors providing custom made semiconductors, capacitors etc.
I would recommend that the design engineers in such positions should properly archive all vendor correspondence, and understand vendors legal terms and limitations of use of their parts.
(sometimes at back of data sheets), or pass on to corporate legal.
Taking advice on a public forum probably won't be regarded as diligent practice in workplace engineering although times are changing.
voltsandjolts:
--- Quote from: sicco on August 24, 2022, 02:55:23 pm ---Double checked with Maxon. They say "We do have customers who use these motors over years at 150°C and pressures up to 20’000 PSI at the same time." So that's what their motors operate at (immersed in clean hydraulic oil, oil that also gets pressured up to downhole wellbore pressures of the same magnitude - pressurised via a seal that communicates P).
--- End quote ---
SLB ESP's use motors operating in clean oil which is pressure balanced with the wellbore, to several thousand psi, but they are custom motor designs with mucho horsepower. You might want search some ESP patents from SLB / WFT and others if interested. Also some info on youtube e.g.
--- Code: ---https://youtu.be/8sTQx5kJq5M?t=153
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Hmm, I'm still skeptical of Maxon off-the-shelf motors being using within high pressure clean oil and would recommend you triple check in case of some language barrier or such like before committing money. And do some early qualification tests. I am happy to be wrong ;D They are certainly used downhole within pressure housings, like Globe also. You mentioned using hall sensors in a brushless maxon motor, but no way hall sensors are gonna survive anything like 20kpsi, so the rep must have been talking about a different motor type, if indeed they do operate at 20kpsi.
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