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Help me pimp my compressor

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Help me pimp my compressor

Unread postAuthor: spudamine » Mon Apr 19, 2010 3:37 pm

So I've just got a fridge compressor, I actually bought one new off of ebay as there are not many abandoned fridges to be found around here, problem is there is no pre-existing plumbing or wiring to give me a clue as to how to hook it up. After a bit of research and taking it to bits I think i've got the electrics worked out. The live terminal block isn't connected to anything, I need to wire it to the exposed connection of the protection device via a switch. the other terminal of the protection device is internally connected to the common pin of the compressor motor. The neutral terminal connects to the run coil of the comressor wire and a PTC (positive temperature coefficient) resistor connects the common and start coils. I was a bit confused by the extra terminal connected to the start coil, I think this is for a start capacitor which this compressor does not require, being a LST (low start torque) model.
As for the plumbing, the label indicates the tube on it's own on the left is the suction, which leaves the outlet and service connection on the right.
Not sure which is which but one leaks oil when I tip it up so I'm guessing this is the service connection and needs to be blocked?
Any help appreciated, I'm also looking out for and additions to make this the most pimped fridge compressor out there 8)
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Unread postAuthor: dewey-1 » Mon Apr 19, 2010 4:15 pm

Here you can find the wiring diagrams and specifications.


http://www.embraco.com.br/portugue/produtos/MP01EG.pdf
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Unread postAuthor: POLAND_SPUD » Mon Apr 19, 2010 4:33 pm

first of all, get all the most important stuff for it, such as a BV for venting the system, hydraulic hose, gauge etc.
once you've got all the basic stuff and it is based on threaded fittings (that would make improving it in the future easier) you might as well add an air reservoir...

once you have all that stuff it might be a good idea to invest in some cooling system and then you can add one or more compressors to it and/or larger tanks
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Unread postAuthor: spudamine » Tue Apr 20, 2010 1:45 am

Thanks Dewey, that's where I found the electrical details although there's no drawings of my model showing which tube is which, does anyone know if the service tube is equivalent to the inlet, I'm thinking of putting a threaded plug on the end of it and using it to top up the oil whilst an air filter can go on the inlet.
@ Poland, I think i've got the cooling covered, see below :D As for the reservoir, I thought about it but it will actually slow me down, I'm going to have a big reservoir on the gun so if I put another one on the compressor as well it will just take my twice aolong to fill :(
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Unread postAuthor: POLAND_SPUD » Tue Apr 20, 2010 2:36 am

damn, where did you get those fans ? they look great and it seems they are of the right power

I'm going to have a big reservoir on the gun so if I put another one on the compressor as well it will just take my twice along to fill
naaah it won't slow you down...

the idea is that the compressor can run all the time, while without a tank you have to:
1. connect the gun 2. turn the compressor on 3. turn the compressor off 4. disconnect the gun

Alternatively you might as well keep it on but then you have to keep the air relief BV on your setup open when you disconnect the gun just in order to prevent overpressurising the setup

Though in this way the compressor pumps only when the gun is connected to it

Anyway it's not somethign you have to add right now... just make sure you can add this feature later
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 20, 2010 4:20 am

POLAND_SPUD wrote:damn, where did you get those fans ? they look great and it seems they are of the right power


...and it doesn't look like a VTOL UAV :D

You are going to put it in some sort of container though, right? It makes cooling much more efficient.
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Unread postAuthor: spudamine » Tue Apr 20, 2010 2:02 pm

damn, where did you get those fans ? they look great and it seems they are of the right power


I, er found them in a cupboard...
they're 120V AC which is a bit wierd but I can wire them up in series for my 250V mains

Poland, I know you posted a link somewhere else about making a compression fitting but the link is dead, could you explain how to do this, the outlet is an annoying 7mm OD, I only have 6 or 8mm fittings :(

You are going to put it in some sort of container though, right? It makes cooling much more efficient


For sure, this is after all going to be a pimped compressor :D can't decide whether to use galvanised steel sheet (which I already have) or alumininium tread plate which would be more bling.
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Unread postAuthor: boyntonstu » Tue Apr 20, 2010 2:10 pm

jackssmirkingrevenge wrote:
POLAND_SPUD wrote:damn, where did you get those fans ? they look great and it seems they are of the right power


...and it doesn't look like a VTOL UAV :D

You are going to put it in some sort of container though, right? It makes cooling much more efficient.


I use no cooling since it is not necessary.

Blowing air around a smooth compressor housing will provide little or no cooling. (no fins)

To add a plumbing fitting, choose any brass coupling fitting that has one side smaller than your comp. tubing.

Drill it to the exact size, slip it on the sanded tubing, add flux, and solder it on.

Works for me at 4 136 854.36 pascals. See it in the video below.

[In 1985, IUPAC recommended that standard atmospheric pressure should be harmonized to 100,000 Pa = 1 bar = 750 Torr. The same definition is used in the compressor and the pneumatic tool industries (ISO 2787).]

Pressure Assisted A/C Compressor for Air Rifle

[youtube]http://www.youtube.com/watch?v=i1lhv18oXZk&NR=1[/youtube]
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Last edited by boyntonstu on Tue Apr 20, 2010 5:15 pm, edited 1 time in total.
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Unread postAuthor: spudamine » Tue Apr 20, 2010 3:31 pm

Blowing air around a smooth compressor housing will provide little or no cooling. (no fins)


Hmm, that's an interesting piece of information, here's another one, have a look at Dewey's link furthur up the page (the manufacturer's datasheet), specifically page 16 as it details compressor cooling which can be static or fan cooled, I wonder who's right? True my model isn't specified as needing fan cooling but neither is is designed for filling spudguns to 40Bar.
Are you saying if you sit in front of a fan you won't feel cool because you don't have any fins :lol:
True, fins would increase the cooling as would loosing the paint job and an aluminium shell instead of steel but the cooling will still be significant with a good air flow.

To add a plumbing fitting, choose any brass coupling fitting that has one side smaller than your comp. tubing.

Drill it to the exact size, slip it on the sanded tubing, add flux, and solder it on
.
Thanks I might try that.

Works for me at 4 136 854.36 pascals. See it in the video below.


:roll: I guess Rag's lessons haven't sunk in yet, you're still adding useless decimal places which you're gauge can't possibly measure...
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Unread postAuthor: boyntonstu » Tue Apr 20, 2010 3:42 pm

spudamine wrote:
Blowing air around a smooth compressor housing will provide little or no cooling. (no fins)


Hmm, that's an interesting piece of information, here's another one, have a look at Dewey's link furthur up the page (the manufacturer's datasheet), specifically page 16 as it details compressor cooling which can be static or fan cooled, I wonder who's right? True my model isn't specified as needing fan cooling but neither is is designed for filling spudguns to 40Bar.
Are you saying if you sit in front of a fan you won't feel cool because you don't have any fins :lol: adding useless decimal places which you're gauge can't possibly measure...



Look at page 77.

If your compressor was not made for fan cooling, adding a fan adds zero.

Imagine blowing air around your water cooled car engine and eliminating the radiator.

IMO Adding a fan is unnecessary.

This compressor has a few fins:

http://www.harborfreight.com/cpi/ctaf/d ... mber=93785
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Unread postAuthor: spudamine » Tue Apr 20, 2010 4:39 pm

If your compressor was not made for fan cooling, adding a fan adds zero.

are you saying that this compressor cannot be air cooled or that adding a fan will not inprove the efficiency of the air cooliing?
A compressor carries out work, it's far from 100% efficient so it gets hot, in turn heating the air around the compressor which rises away from the compressor and sucks more cool air in. It's called a natural convection current, add a fan and you have forced convection which can be hundreds of times more effective at moving air.
Your compressor may indeed need no fan, it's not enclosed in any way and it's outside in moving air. mine will be fitted into a rugged compact enclosure, fan cooling costs me nothing and can only improve the lifetime and performance of the compressor.
If you have found some other magical way your fan keeps cool other than air cooling I would love to know what it is, I'm doubting radiation off of the surface or conduction into the ground are very significant.
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Unread postAuthor: boyntonstu » Tue Apr 20, 2010 5:14 pm

spudamine wrote:
If your compressor was not made for fan cooling, adding a fan adds zero.

are you saying that this compressor cannot be air cooled or that adding a fan will not inprove the efficiency of the air cooliing?


See my A/C compressor in the video?

No fan would cool it, no matter the size.

Refrigerant compressors are designed to be cooled internally by the refrigerant that flows through it.

A fan blowing air over your chest will not cool your liver.
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Unread postAuthor: POLAND_SPUD » Tue Apr 20, 2010 5:33 pm

it does work... sure it would be better if there were fans...
it is possible that a fan is not needed on a compressor with fins (provided that their surface is large enough and that they conduct heat really good)

but I wasn't able to fins a way how to mount these things to the casing

@boytnostu
damn... what is your problem ? you're probably the oldest member on here and we all appreciate your work... but you are acting like a 11 year old kid (note - it's just a figure of speech... I've never seen anyone that young who behaved in this way)

Why can't you just get over it ?
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Unread postAuthor: MrCrowley » Tue Apr 20, 2010 5:39 pm

A fan blowing air over your chest will not cool your liver

Why not? I'm no expert but if you lower your core temperature, which a fan blowing on your chest probably could do, then I don't see why the temperature in your live could also not decrease.
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Unread postAuthor: the unit » Tue Apr 20, 2010 5:41 pm

Actually it would cool your liver, as the blood that passes through the capillaries/veins/arteries in your chest would be cooled and this would in turn cool your liver, as cooler blood passes through your liver. It is how your body maintains homeostasis.

On topic though, adding a fan is not going to increase heat to say the least, and it should cool the compressor so it won't hurt to add the fans.
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