Electronics > Projects, Designs, and Technical Stuff
Calculating heat dissipation requirements for high pressure compressor... ?
NiHaoMike:
--- Quote from: pipe2null on May 20, 2020, 07:05:25 am ---And I am very very curious about the Prius inverter, maybe not as a 120V solution, but as a multi channel multi phase AC power supply for my lab. Could it take un/rectified 240VAC direct? How bad is the THD? Where can I get tech and/or hacking info? Hehe... I think I need to attend a TEA meeting. But seriously, more info please!
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https://openinverter.org/forum/viewforum.php?f=14
You can just connect two phases on one of the inverters to 240V, but unless you're planning to use it to backfeed power (as I will for my solar inverter project, carefully controlled by a FPGA and sensors) it's a waste of inverter phases. Just add a bridge rectifier in order to use the buck/boost converter as a PFC stage.
--- Quote ---My issue with electrical power in my apartment is that decades ago they wired half the lights and outlets in the unit to a single 15A 120V circuit. Nearly all the other circuits in the breaker box are dedicated to specific things, like dishwasher, kitchen outlets, water heater, etc. My second bedroom/lab/workshop is not exactly wired to be a lab/workshop. Even if it can handle my addition of an air compressor, I keep adding equipment and it won't be long before I'm tripping the breaker on a regular basis. The property owner of my rental unit doesn't care about the improvements I make as long as they are up to building code and legally speaking do not require a building inspector visit. So, I cannot modify the breaker box, but i can put an outlet on the existing unused 20A 240V circuit in my lab. Good tip on the "flip the 110V->220V" switch on power supplies... That didn't even occur to me.
What I consider a "cheap" solution for 120V: The price difference between the 120V and 220V HPA compressors I've been looking at is around $150 for the same thing at different voltages, the 220V costs more. So, a solution that let's me (optionally) stick with 120V equipment purchases that are easier to resell later is worth at least $150ish.
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Check if the stove circuit has a neutral, which they often do. In that case, make some sort of adapter with circuit breakers for overload protection. Then run some good quality 12AWG extension cord(s) to your lab. You can either have a pass through to allow the stove to still be used (it will only pull near its rated power if all burners in use, which you can avoid doing) or buy an induction cooker.
max_torque:
It seems crazy expensive and crazy dangerous to have 4000 psi in your house, in an untested / certified system, in a domestic setting.
What do you need the HPA for? and how much do you actually need? You can simply get an account with one of the usual HP gas providers and buy a HP cylinder when you need it, or, get your local scuba shop to fill small tanks. Given you can buy a fully certified 10l scuba tank for a couple of hundred $ and a typical fill is 5$ why would you mess around doing it yourself?
I'd also say that "i'll test it outside" is in no way a suitable level of safety for testing a prototpe HP system operating with a compressabel fluid (Cylinder cert is done with un-compressabe fluid) You'll also have to check your local laws that set the requirement for HP cylinder visual and hydraulic testing (in the UK, it's visual every year, and Hydraulic every 5 years for steel tanks)
max_torque:
Oh and trying to use a HP compressor as a LP compressor is unlikely to work, simply because the HP compressor will have a tiny flow capacity. If you only use small amounts of LP air, then you can of course run that off a small HP cylinder though a suitable adjustable regulator. Even the large, powerful HP compressors used by commercial businesses dealing with compressed gases tend to be used to continuously trickle fill a large "bank" of HP storage cylinders, and those cylinders provide the higher flow rate to quickly fill the end-users cylinders.
pipe2null:
--- Quote from: tautech on May 20, 2020, 02:35:15 pm ---
--- Quote from: pipe2null on May 18, 2020, 02:08:07 am ---I have occasional use for high ~3000psi pressure,
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Do tell what for ? :-// :scared:
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I was wondering when someone was going to ask that one. Heh.
First of all, I take safety very serious, and I hope I've made that point clear to everyone who has posted here. Improperly set up HPA is extremely dangerous and can result in explosions, various types of missiles, and high velocity shrapnel. So, yes, I take related safety seriously. But like any motor vehicle, HPA is safe when properly and responsibly used. A crazy driver can get on the highway and cause massive property damage, injury, and death, similar to improperly set up HPA. The big difference is the danger involved with a crazy driver is very obvious, but the dangers involved with HPA are NOT obvious and require not only good sense, but also experience in identifying the danger points. When it comes to the safety of others, I am good at exercising good sense, but I lack sufficient experience working with HPA to design a guaranteed-safe system. Some required safety bits and pieces are obvious, others are not.
Some posters on this thread have shared some of their valuable experience, and I greatly appreciate that (and so do my neighbors). Please be assured I am applying that good advice to make sure all required safety mechanisms are in place and tested as much as feasibly possibly long before even plugging in a HP compressor.
To answer the actual question: Well, I have several uses for high pressure, and that is assuming I do not get back into SCUBA any time soon. I still have a closet full of underwater gear that I should probably either use or get rid of... Spring cleaning for another day. But I digress. I've been trying to get my nephews interested in building a robot with me, since they speak some new fangled language my older ears do not understand, figured robotics might be a good rosetta stone so to speak. I'm not going to give them any HP components, but I have some ideas I want to try out adding pneumatics to a mobile platform. I also have a few friends that are into guns and go to an outdoor range pretty often. I'm not really into the whole firearms thing, but picking up a high powered air rifle to "me too" without compromising on the "fire"arm part would be good I'm thinking. The main reason for high pressure, and my immediate need for air compressors in general is adding pneumatic part development capabilities to my lab. I'm currently working on several projects for 3DP pneumatic parts and I need several different pneumatic power rails (aka low pressure manifold with several low pressure regulators putting out different pressures). Plastic has been used to convey pressurized material for a long time. Plain old PVC can safely contain a substantial amount of pressure, with >1000psi rupture point. The single biggest problem (due to safety) with 3DP pneumatic parts is the unpredictability of the rupture point, and where in your design the rupture will occur. The second biggest problem with 3DP for pneumatics is very poor dimensional accuracy and repeatability, but much of this can be overcome using o rings, normal metal springs, and other non-printed bits and pieces. It is not a small challenge to come up with practical 3DP pneumatic designs. But being a responsible designer requires significant testing, including destructive testing. I have an outdoor steel enclosure with steel grating over vents that is suitable for failure testing parts with very thin plastic walls, but even that basic testing will require a little more pressure than a typical consumer air compressor can produce. Doing failure testing of parts with thicker walls will require a trip to an outdoor gun range or similar location for obvious safety reasons. There is no practical way to test the reliability and safety of a design without destructive testing in a safe and controlled manner, like placing the DUT in a vented steel enclosure and then over-pressurizing the thing until it fails. I'm sure I'll come up with more uses for HP as time goes on.
To put my HPA "system" in perspective, it's basically a small 350mm x 175mm x 360mm HP compressor, a pony sized HP tank, plus all the necessary bits and pieces for safety. Compressor and tank will be located directly next to each other, no long haul HP piping. No matter what, I will still need an adjustable regulator for HP to LP so destructive tests can start at very low pressure and brought up slowly until DUT rupture. A pony tank should have enough capacity for a single destructive test, but if also using "system" for LP, will probably use a normal sized scuba tank, but in no scenario will I have larger than a 120 cuft scuba tank (like I used to own).
As far as trying to use an HPA system also for LP: The thought is simply that once I have a small HPA system designed and SAFELY built, not much else is needed to also use it for LP. Since my home is space constrained, minimizing square footage by using a single HP compressor with HP tank of conservative size instead of both an HP and separate LP compressor with comparatively very large LP tank would be a very good thing, although not a 100% requirement (more like 95% required).
It is extremely inefficient to use HP for LP, but no reason you can't do it. The tricky bit here is not how to use HPA for everything, but how to design and construct the HPA with all safety concerns addressed, with or without the LP step down. I owned and used HP scuba tanks before, even had them turned and certified for nitrox, but setting up that same tank for continuous use and connection plus the compressor (for attended use only), has significantly different safety needs that I am not sufficiently familiar with yet.
tautech:
Thanks for the lecture but you're a braver man than I.
Played with HP hydraulics, diesel injectors and air compressors most of my life and even built a couple but 3k PSI air I won't go there....shit it rhymes ! ::)
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