LET THIS SIGNAL THE END OF THE FRIDGE PUMP QUESTIONS!

My contacts are gluing themselves to my eyes! Don't give up yet, I doubt you've ruined it.

Having scrolled through the PDF and searched around for a good while, I've discovered the P in the code on the side of compressors standards for "PTC + Run Capacitor (optional)"

The PTC is a disc of material, it's called a Positive Thermal Coefficient relay. When it's cold, it has a very low resistance and will energise the start winding. It almost instantly warms up, the resistance rises, and it disconnects the starter winding - largely.

Here's a picture of one, it's the cylinder in the centre.



Here's the assembly off the side of one of the pumps I have. You can see inside the overload switch, although a piece of it is missing. The thing below it, the thin cylinder, is this one's PTC.



If I flip it over... you can see the PTC is sitting a bump sticking out the plastic moulding. This may be what the plastic bump is in yours between the two blocks I've labelled as live and neutral. Which suggests you have the PTC it needs.

You can see I also have some spare starting capacitors, if you find you need one you can have it for the postage.



The rest of the code standards for Embraco Mini Compressor, 2nd generation, R-600a refrigerant, Low Back Pressure, PTC + Run Capacitor (optional)

This band of units, it appears, are low starting torque units. Not only does the P code say the RUN capacitor is option, it states that is a START capacitor is mandatory for others. All that suggests you don't NEED any form of capacitor.

The question is now where to connect the live and neutral connect. Scrolling through the schematics, only two of them use a PTC, and only one of them is for the EM line - on page 23, the top left schematic.

The mains goes to pin 3 on the OVERLOAD switch, and pin 2 on the PTC.

I can see a pin marked 3 on the overload.

The PTC looks nothing like the circuit schematic drawing, and I can't see any numbers in the photo. Can you have a closer look at it in person and see if you can find any more numbers.

Are pins 2 and 3 on the overload switch even separate spade connections, or connectors?

In the meantime... here are some top trump factors for your compressor!

It has a 5.19 cubic centimetre displacement, a 64W heat moving capacity, a 0.98 Co-efficient Of Performance and is using ester based oil.

Curious, because further up the PDF it says the R-600a's use alkylbenzene and mineral naphthenic. The letter L in the code on the casing is also not used in the EM range of codes, yet the compressor clearly belongs to the EM range.

Have a GOOD look over the other terminals for some more numbers. If there is a spade connection on pin 3 of the overload switch, that should be one point for the mains.

On the PTC, that looks nothing like the schematic drawing of it. There is only one point the mains needs to connect to on the PTC, and I think it may be the one I've labelled as 1. Again, check for numbers around there.

Also, try sticking the multimeter on pin 3 of the overload switch, and then the pin I've labelled as 1. In the schematic, if these are the two pins they're on about, that should have a motor winding and the PTC between it. Which should give a low resistance reading, but one more than zero.

[Edited on 6-2-2011 by peach]

Quote: Originally posted by IrC

I think you guys are wasting your time using these pumps unless you are looking for a distillation setup or a roughing pump. [snip] For a decent laser you need to get down to say 60 microns or lower.

Indeed.

However this is primarily a chemistry forum, as opposed to physics, so I assumed most people would be more interested in filtration, distillation and vacuum drying.

And your point about the cheap rotaries is one I made myself in the video. But quite a lot of people here also have next to zero money to spend on individual parts when they need so many different, and equally expensive, things for at home science. It is there hobby, they make no money out of it, a good number of them are young (which also means not particularly good money wise) and, since they're interested in science, they will be in for a rough ride when it comes to paying for the rest of their education.

I'm not messing people around when I say I still use fridge compressors for chemistry. In fact, I use them most of the time and one of them is running right now.

This is not because I can't produce a higher vacuum, there are other factors at work.

A lot of the fun of doing science at home for me is trying to see how little I can get away with using to produce the same result. In the case of vacuums, it goes further in that, if you connect a rotary to a volatile solvent, without a dry ice or liquid nitrogen trap, it's going through to the pump.

There is also a reasonable possibility that the pressure these pumps can achieve can be lowered. It's just that I haven't got round to checking all of the ideas yet. Pfeiffer have managed <0.1mBar with piston layouts; with 0.1mBar being 75 microns.

It's worth remembering that a lot of the poorest people in the world, who can't afford a physics lab vacuum pump, also have access to piles of fridges and freezers. It's quite likely the progress of science in these areas is being blocked by things like... them not being able to get a pump to do a filtration or to pull a flash column. The wider spread the information is, the better.

In terms of those people being stupid or too cheap to spend money when it's needed, I have seen more than one chemistry blog online by someone who has a PhD who is also connecting solvent boil offs to high vacuum lines, and then complaining about it getting through the trap.

Also, in more than one example, their solution was to simply throw more and more money at it rather than swap the vacuum source to something more suitable. We should not be blindly throwing tens of thousands of pounds at boiling a solvent when it can be done with something from the tip and tuition fees are having to be tripled, effective immediately.







[Edited on 6-2-2011 by peach]

Greetings all, It's been several years since the days of the E&W forums. Having looked around and found a source of rogue research lacking in my life. I've decided to crawl back out from the rock I was quite comfortable living under.

My father before me was/is a journeyman appliance repairman. I took up his mantle adding several sciences and computer technician to the list. I figured a first post here squarely in my back yard was a good choice.

Peach, Kudos for taking a compressor. They are soo not intended for open (but can be repaired once open) maintenance as you have well now discovered. Also congrats on a similar pile of old tech to my own if the pictures are indeed your house. I saw large old caps and what appeared to be a large toroid transformer in the piles behind the pictures. It needs about a dozen MOTs and random glassware scattered about and it would be home. OH I also understand your pain at kissing goodbye a fluke123 I had one and turned it in because i needed a feature it was lacking, can't member what... Anyway a uni-T ut55 and a Fluke Pv350 fills the void, with less void in my wallet mind you.

Mossydie, you pretty much can't kill the compressor by wiring it wrong, the windings for example are already just a short across the terminals with a couple hundred feet of motor windings between them and having 2 mains wires on the same terminal will simply blow your breaker(also a good suggestion Peach). More likely whats happened since its a brand new compressor is it's become frozen in its state. The oil used isn't exactly top shelf and it can cause parts to adhere if left for long periods of time. Warming the entire unit up maybe an option as would a start capacitor. Your idea of removing the whole plastic housing crap is what I would do to get to the bottom of this. the 3 exposed terminals can be wired to directly and in fact a commercial start cap has special spade connectors that also fit tightly on the round pins of the compressor housing.

Pictures really are worth a thousand words can you take more of the plastic POS and the compressor itself the 3 pins (on the housing itself) will be marked either with numbers or better yet, letters. Often that plastic housing has bi-mettalic straps or likewise to pull the connector pins away from the connection with the compressor housing(once started). Hence the reason the commercial starter repairs are designed to fit right onto the pins.

I've attached a couple pictures of start caps there cheap like 10 bucks cheap. The high voltage one is usually what comes in a microwave. It was sold to me at my usual parts watering hole as a start cap but my own experience tells me otherwise (that and the only 2k voltage rating you will find in a house is your microwave, or a CRT tube but that doesn't need a start cap). A 10 MegOhm resistor is inside it and will discharge the cap under normal power down circumstances.

The second big chunky guy is more like it 17.5 MicroFarads and 370 volts 50 or 60hz , universal no matter which side of the pond your on.

Finally I don't understand the haters for these machines. A more lowly appliance doesn't exist and yet your simple fridge compressor can heave over a 1000 psi and draw vacuum in excess of -27 inches of Hg. A scrapped fridge and 100 bucks of ebay glassware lets you distill anhydrous nitric acid. What on earth is there to complain about ? It doesn't grant wishes and offer sexual favours?

Here are three labelled pictures of all the connections I can find:


The pins with the unit removed


The front of the unit


The back of the unit


The resistance between the push fit connection and the neutral connection on the front (when the unit is removed from the pins) is almost identical to the resistance between the lower two sockets for the pins - so I'm guessing this is actually a measure of the resistance of the pcb when cold.

I tried connection the mains a different way: neutral to neutral, live to the piece of metal I've labelled as suspected 'pcb connection'. I got a similar vibration and humming but no obvious movement of air.

There is a number three on the overload switch, but it's next to just a raised bit of plastic. I though it might refer to the metal connection underneath the overload ('pcb connection')?

[Edited on 6-2-2011 by Mossydie]

Quote: Originally posted by Regolith

OH I also understand your pain at kissing goodbye a fluke123 I had one and turned it in because i needed a feature it was lacking, can't member what...

Let us both have a moments silence as we remember, those good times with the 123.

Press the green button... click... nice...

I wanted the thermocouple for mine. I actually had two, because I sold one, then found I needed it for something, so bought another and then sold that as well.

The second one had the FlukeScope optical isolation lead and software, which only made it even more bad ass!

At the same time, I found myself thinking, this is without question the best multimeter on the planet, yet the scope isn't all that great. But then, a scope of the same price probably isn't going to have the multimeter functions the 123 has.

I can appreciate how someone who works in industry, wandering around plants, would love having so much in one thing that can be put back in the bag, and wouldn't be too bothered about the lack of detail on the scope so long as they could spot some triggering glitch and report it.

The big capacitors are part of some 30 amp linear regulators. There are indeed toroidal transformers, MOTs and magnetrons on the desk. I have tons of photos of my glassware and other things on my facebook page. I'll send you a link in a second if you want to troll through some nerd porn.

Quote: Originally posted by aonomus

Quote: Buchi make controllers and pumps like this. Needless to say, the price is eye watering. These controllers usually go on 10-20L preparatory rotovaps like the ones they make. I happen to use these on semi-frequent occasion as well. Its neat, the pumps are all inert with teflon/glass innards and the motor will run at high speed until reaching the rough set point, where the motor spins down and it can even execute individual pump strokes to maintain the pressure within +/- 1 torr ripple.

I'm sure I know someone who can program microcontrollers on here... just trying to remember... who....

Quote: Originally posted by Mossydie

Erm...nope, the caps were still in

Quote: Originally posted by peach

Awww..... it still has the caps on from the factory, the innocence!

The problem more like!

I was standing in the kitchen at 4am thinking, maybe he's left the caps on, and thought.. "Nah... he's not left the caps on".

Never mind! So long as it's working, it's good.

The little puck shaped thing isn't a PCB, it's a PTC, a thermistor which changes it's resistance based on it's temperature.

In this case, it's starts off with a low resistance, a big surge of current goes through when the mains is applied, it warms up and it effectively switches off the circuit it's connected to by putting a big amount of resistance in the way. So it's normal for them to warm up.

PTC is actually telling you the type of thermistor, that it has a positive temperature coefficient.

There is an opposite to that, called the NTC (negative temperature coefficient).

They get used to prevent surges. Say you have a lot of capacitance in a power supply, straight after the transformer and rectifier (almost directly on the mains), as soon as the supply is plugged in, the capacitors look like a near perfect short circuit until they're charged up.

You can add NTC's to the supply which block the instant surge and only let the supply function at it's maximum current once they've warmed up.

Those power supplies above do it. They have zero form of surge protection, but have very large capacitors pretty much directly on the mains. If I plug them into a normal ring socket, they'll trip the breaker. They have to go on the cooker socket, the cable and breaker for which is designed to handle three to four times more than a ring mains. It's one thick cable, directly from the breaker board. The only other such line you'll find in a house is for an electric shower. Both are extremely dangerous in terms of shocks and fires, and subject to special notice in the Part P regulations of the building codes.

In terms of changing the oil, someone on the last page mentioned Silicone oil. The things to consider in terms of changing the oil are;

a.) will it decompose when contaminants get through and
b.) what is it's vapour pressure

Vacuum pump oils need to have a low vapour pressure, or they'll start counteracting the effect of the pump by releasing gas of their own. Silicone is used in diffusion pumps, where the oil is going to be heated, encouraging vapour pressure problems.

Quite a common theme with low vapour pressure oils is that they typically have a higher boiling point and, more importantly for us, they are usually thicker!

The thicker the oil is, the more energy the pump has to put into churning it. As I say earlier on in the thread, I have tried replacing the oil in one of these with actual rotary pump oil and, without checking it with the thermometer, I seem to remember it was running a bit hotter with it in place.

It had gone from a normal cup of coffee temperature to one that's just come out the kettle, so perhaps 10-20C hotter.

Using thicker oils, I would recommend you think about sticking a computer fan to the top of the pump. I doubt it'll overheat without one, but running the pump a little cooler will improve the vacuum and make it less likely to seize.

I've never had a single fridge compressor stop working in the middle of something. The one I have switched on now has been on for over two days, and it's still running.

If they're going to seize, it's when you switch it off. As the metal inside has warmed up, expanded and needs a little time to cool down. It's a good idea to leave the pump running all the time as you work, rather than switching it on and off and risking it needing time to cool down when you need to do something quickly.

[Edited on 7-2-2011 by peach]

Your very welcome Mossydie as I said it's kinda what I do

To everyone who is curious about changing the oil in the pumps. The short is answer is yes you can use whatever fluid in the pump you want but as mentioned its vapour pressure has to be such that it doesn't vaporize under the vacuum and the heat of the pump, also it must not react with the gas your passing through it (there shouldn't be any contamination going through the pump though, more on that in a sec).

It's uncommon for a repairman to have to add oil or change the oil in a compressor but leaks happen and it does occasionally happen. There are many kinds of compressor oil, esters, several hydrocarbons with anti-foaming additives etc.

Food grade Mineral oil is what I feed my pumps (can be had at most drug stores). To drain cut the oil fill line the one near the bottom of the compressor and open the vacuum in line to allow airflow. This works best right after an hour or so run to warm the oil up and decrease the viscosity. Old oil REEKS don't get it on you since you have no idea what it was some of the esters and even mineral oil will break down over time under the heat of the pump. Tilt the compressor to drain if you have a bucket or something that can support the pump at the correct angle that would be advantageous.

Filling is the easy part reseal the oil line and simple run the compressor and let it suck up the same volume of oil you recovered from the pump. Under normal condition mineral oil shouldn't eat rubber seals etc if your pump has them(mineral oil doesn't leech chemicals from the seals).

Now onto why your pump shouldn't be sucking up anything. There should be a trap on the line out from your compressor a stainless steel can or otherwise (I have an oil trap somewhere but I can't find the damn thing its looks exactly like my vacuum bottle minus the internal implosion support and the vacuum gauge). Even with the measures put in place to try and keep compressor oil in the compressor it will push oil out over time and ESPECIALLY when you break a hard vacuum seal on your glassware when distillation is complete. The oil capture bottle should be above the level of the compressor so as to try and keep oil from even getting to it but no more than 30cm away from the compressor otherwise it could pump all its oil out before you even knew it. After each distillation throw away the oil that has been aspirated out and let the compressor eat new oil of the same volume. In this way I avoid doing a full oil change over time and the oil that is aspirated out doesn't smell of Ass mixed with More Ass.

The vacuum bottle shown is your first/last line of defence in keeping your pump happy. Before the compressor but after the bottle. I use a 20cm length of pvc pipe with caps and plastic connectors at both ends and the pipe is secured to the wall so as not to disrupt the contents. These pipes (I have a couple depending on what I'm distilling) can be filled with something as simple as anhydrous magnesium sulphate (epsom salts) to capture water from the airstream. To something way more hardcore like large prilled Sodium Hydroxide to scrub oxides of nitrogen out of the air and acid vapour that you don't want in the pump.
NOTE: these pumps are Hermetic meaning under normal operation (if your name isn't Peach) there isn't an exchange of air from the compressor circuit. So when distilling things like Nitric Acid it CAN (be insanely super careful and at the very least get a full face shield or a good pair of goggles, skin can regrow the clear proteins of your eyes will denature and be lost forever) be done inside with the output of the pump connected to a good hose that goes way outside. An NaOH scrubber removes pretty much all the NO and NO2 from the air and when it becomes ineffective from use you dump the scrubber contents into water and separate out the moles of Sodium Nitrate you made.

Many lab pumps don't have things like acid traps before the pump and/or there not used always which is why lab pumps often look great outside and beat/eaten to sheeet inside.

Finally Mossydie: shown is a beaker from a recent experiment. While drying a nitrate in my lab microwave (don't use the food microwave for chemistry, random poisoning < Good times) the water boiled off as I watched and then the reaction continued the microwave happily melted my sodium nitrate sample right to it's decomposing temperature. I ran and grabbed my respirator so as to watch this more carefully as the nitrogen oxides smell like nothing else and you don't want them IN you. Indeed no water was left and it was an anhydrous sample. More amazing the beaker didn't crack or shatter upon cooling from the stresses in the glass.

Curious I fired up the hotplate and took a sample of the same nitrate to molten. The beaker is the one shown in the picture. The microwave acted as a furnace containing heat and heated the sample not the glass meaning there were far less stresses placed on the glass beaker. I have yet to really play with this as it happened a couple days ago. I very much wish to attempt a reduction of nitrate to nitrite via a microwave, of all things.

Peach is right about organic chem temps. The most badass glass mercury thermometer I have goes to 320C (I only have a couple left, try getting bubbles out of mercury when you have to take the glass to 350C to max it out and clear the bubbles). I bought them then ironically figured out to use a broken thistle tube with the end melted shut and a type K thermocouple inside the tube with a drop of mineral oil to make better contact with the tube itself. The whole point of distilling things like nitric acid under vacuum is to lower the boiling point beneath that of its decomposing temperature (and save glassware). Essential oils with very high thermal mass will almost certainly be destroyed taking them to there (natural) boiling point to distill them.



[Edited on 7-2-2011 by Regolith]

Quote: Originally posted by peach

For those in doubt, please have a read of the following post for why fridge compressors are a good idea

Quote: Originally posted by entropy51

What's all the yelling about? Amateurs have been cognizant of, and extensively using, fridge compressors as vacuum pumps since even I was a wee lad. Does "re-inventing the wheel" ring any bells? Sheesh. There's an old thread on this topic from 2003. Old news.

Quote: Originally posted by IrC

I think you guys are wasting your time [Edited on 12-19-2010 by IrC]

Quote: Originally posted by entropy51

1. Connecting the house mains current to the two proper terminals and 2. Momentarily connecting a starting capacitor across the two proper terminals with a pushbutton switch. The switch is depressed until the unit starts (a second or two) and then released. If your compressor is this simple you basically just have to identify the proper terminals and find a start capacitor of the proper rating (microfarads and voltage). The tables in that pdf should help with this. Good luck!

If I may make a hypothesis based on observations here. This board much like past boards I have been on has a significant Kewl population, so much so my laptop runs colder just being here .

That said I'm not implying that irc or peach are kewls (or mossydie for that matter, only through asking questions can we increase our knowledge). It seems though for a lack of a certain green preying mantis (I miss you meglo), this forum causes as much frustration at times as it does provide useful knowledge.

Irc is working on a plasma vapour deposition rig, Peach is looking to continue his education to further increase his human Ark potential. Mossydie is making a pressure chamber to test gerbil space suits for his mutant gerbils, all hail our gerbil overlords long may they rain(this last part MAY not be true).

The point is there isn't a need for those of us who pursue true science to chew at each other, especially when we pursue goals that are different. I mean how Irc is measuring his double digit (or single depending on the Mayan gods and nature abhorring a vacuum) micron vacuum without a visible non manifold based gauge has thus far eluded me. I'm not ripping on him for it though. As a fellow scientist I conclude he must have a means of testing his own experiments.

My own personal example is thus. Upon seeing Irc's footer of "There is no magic, only science". I took this to assume he had no faith in a christian God. My patience was rewarded by his counter rant "wreck my Christian way of life". As with science life requires patience.

Silane hey...

One hexachlorodisilane vaporiser and controller. That guy on the side looks in a bad way.

What are you planning to coat? By fusion, Farnsworth?




[Edited on 9-2-2011 by peach]

Quote: Originally posted by Regolith

The most badass glass mercury thermometer I have goes to 320C (I only have a couple left, try getting bubbles out of mercury when you have to take the glass to 350C to max it out and clear the bubbles).

bit of feedback

Well I'm bumping this thread because I FINALLY got my grubby hands on an old mini-refrigerator .

I haven't taken it apart yet, but its got a pretty interesting wiring. The compressor looks nice though . Hopefully this little thing will last me many experiments/distillations/filtrations.

I'm sure I'll need some help figuring this thing out so I figured why not bump it in advance hehe...

Cheers again peach, your youtube videos and this thread help a shit-load.

Good call, it's a mini-fridge and the schematic mentions nothing about a capacitor unless it's inside the pump box itself? It's kind of older and has been sitting for months in someone garage until given to me. So I'm assuming it's safely discharged if there is one.

The weird thing about this is the thermostat control seems to lead directly to the pump, and the main's cable does as well? Two green grounds are fixed to the bottom plate. Guess I'll try to figure this out another day, thanks for the tips though .

Well I connected the black wire to the white wire and completely left out the thermostat controller. The pump works again, it pulls air, it seems pretty weak but I'm sure it'll work perfectly . I'll bust out the solder gun, make this sucker official. FINALLY I have a vacuum pump, stupid water aspirator.

I might try to wire a little computer fan on-top of the pump to help keep the pump running cold. Hmmm, we'll see .

[Edited on 7-3-2011 by smaerd]

{edit}Chopped, since you've got it working in the time it took me to click reply {edit}

***I would stick to calling it the earth. Some people call it the safety ground, but the ground rail in a power supply is the thing that completes the circuit back to the power supply; it's designed to carry power when the circuit is on. The earth shouldn't have any voltage on it or current through it unless there's been a fault (usually the live touching the case). So I think terming one 'the ground' and the other 'the earth' is safer than using 'safety ground', because calling them both grounds is asking for confusion on something really important. The ground rail can sometimes be connected to earth (e.g. the neutral coming into your house is connected to earth), but the purpose of a ground rail and an earth are quite different. The neutral from the grid is there to carry power. The earth is there to carry faults.

[Edited on 7-3-2011 by peach]

Makes complete sense . Thanks for posting that naval electrical engineering training thing as well, very useful. Oh yea and thanks for making such a comprehensive thread with videos about all this.

Here's my little modification. It's not perfect I wish the little top container was bigger and had better thermal connectivity because of the concave shape of the compressor. Though it does touch maybe 4inchs^2 of surface area, which is okay for now until I find something better. It's PP5 so it should endure temp quite nicely just in-case. The tape is pretty ghetto but I couldn't think of anyway around it.

Anyhow how does this look , keeps the pump cool and has a little solvent trap in-case anything escapes the receiving flask. Sorry the lab is a little messy.

Still need a means to empty the little container, maybe I'll find a spout in one of those old margarita mix containers or something.

Well my pump took an unfortunate belly-full of water today .

So I used my aspirator to remove all the oil and water inside. Flushed with WD40 several times, and removed it via vacuum. Sprayed a little WD40 and is still runs but makes a lot of noise, so it probably needs R12 oil? Or is it likely totally f*$&ed?

So I flushed it out with R12 mineral oil, and now it faintly hums for maybe 30 seconds then there's a large click and an electrical spark going from something in the box to the ground . I think it's toast!

Well I tracked the spark it's going from the over-load to the ground. Not sure if the problem is the over-load or the relay, they see to be in perfect condition but obviously when the vac over-loaded from not being able to compress the water it must have blown something. It's just strange because it WAS running before I picked up the oil. Albeit loud but it was running.

Edit - nvm I don't want to win a darwin award. I think the problem is the Start Relay, wonder if there's a way around it...

[Edited on 15-4-2011 by smaerd]

So I took apart the relay assuming that was the problem, some of the thermiser was oxidized so I scrubbed it with steel wool. Plugged it in no dice. Took apart the over-load, there was not a single sign of damage. So I am assuming the pump is stuck of struggling. Peachy any idea?

Picture attached below is the start-relay taken apart amazing how these things cost $40 a piece hahaha. The most expensive component in it can be ordered for 15 dollars...

Quote: Originally posted by smaerd

Here's my little modification. It's not perfect I wish the little top container was bigger and had better thermal connectivity because of the concave shape of the compressor. Though it does touch maybe 4inchs^2 of surface area, which is okay for now until I find something better. It's PP5 so it should endure temp quite nicely just in-case. The tape is pretty ghetto but I couldn't think of anyway around it. Anyhow how does this look , keeps the pump cool and has a little solvent trap in-case anything escapes the receiving flask. Sorry the lab is a little messy. Still need a means to empty the little container, maybe I'll find a spout in one of those old margarita mix containers or something.

Quote: Originally posted by mycotheologist

I'm gonna go to a recycling centre and find an old fridge but what kinda tools will I need to salvage the compressor? I don't wanna go there for nothing so I have to be prepared. [....] I don't wanna leak freon into the atmosphere so I'll figure out a way to trap it instead.

Looks like I better forget about capturing the refrigerant then. Do I have to cut the refrigerant lines to get the compressor or can I leave them alone? I don't have a car to carry my tools, its a 15 walk from the bus stop, I was thinking of just bringing one of these:

a screwdriver and a few other lightweight tools, will that be enough to get the compressor?

Quote: Originally posted by mycotheologist

Do I have to cut the refrigerant lines to get the compressor or can I leave them alone? I don't have a car to carry my tools, its a 15 walk from the bus stop, I was thinking of just bringing one of these: [...] a screwdriver and a few other lightweight tools, will that be enough to get the compressor?

Fridge Compressor for Vacuum

Please <img src="./images/xpblue/top_search.gif" /> <a href="search.php?token=&srchtxt=compressor+vacuum&srchfield=body&srchuname=&f%5B%5D=all&srchfrom=0&filter_distinct=yes&sea rchsubmit=Search">Search</a> before starting new threads. And don't forget that there's an entire world of <a href="http://lmgtfy.com/?q=refrigerator+compressor+vacuum+pump" target="_blank">information</a> <img src="../scipics/_ext.png" /> outside of SM.

[Edited on 30.7.13 by bfesser]

Quote: Originally posted by bfesser

Please <img src="./images/xpblue/top_search.gif" /> <a href="search.php?token=&srchtxt=compressor+vacuum&srchfield=body&srchuname=&f%5B%5D=all&srchfrom=0&filter_distinct=yes&sea rchsubmit=Search">Search</a> before starting new threads. And don't forget that there's an entire world of <a href="http://lmgtfy.com/?q=refrigerator+compressor+vacuum+pump" target="_blank">information</a> <img src="../scipics/_ext.png" /> outside of SM. [Edited on 30.7.13 by bfesser]

Thanks for the funny video

Vacuum pumps from consumer products (compressor modifications)

Quote: Originally posted by RogueRose

I am in need of a vacuum that can pull a pretty high level of vacuum (ideally 24" Hg.) for an extended period of time (maybe 30 mins on - 10min off - repeat). I am capable of adding some kind of cooling to the compressor whether it is mearly a fan or enclosing the housing with a water jacket & running cold water through it - IDK what else may be possible. I know fridges and freezers have compressors that will work for vacuums but are there other products that do as well? I would think maybe AC's and dehumidifiers may have something like this? Anyone have any suggestion of other products?

Quote: Originally posted by dicyanin

Water cooling is overkill, I used a ventilator on my fridge compressor, continuously blowing air on the top of the compressor. I have been able to perform a 12 hour vacuum distillation that way without triggering the overheating sensor. Recently I've read somewhere that the max. strength of a fridge vacuum pump/compressor could be increased by adding the right kind of hard start capacitor. https://www.aliexpress.com/i/32965670749.html?spm=2114.12057...

Quote: Originally posted by RogueRose

I am in need of a vacuum that can pull a pretty high level of vacuum (ideally 24" Hg.) for an extended period of time (maybe 30 mins on - 10min off - repeat). I am capable of adding some kind of cooling to the compressor whether it is mearly a fan or enclosing the housing with a water jacket & running cold water through it - IDK what else may be possible. I know fridges and freezers have compressors that will work for vacuums but are there other products that do as well? I would think maybe AC's and dehumidifiers may have something like this? Anyone have any suggestion of other products?