Annoying Compressor fault....?

[rtbcomp]

^^ Do not flame, and if you disagree say what you disagree with and why.

 

[Noods]

Water injected into a combustion chamber is help elevate detonation.. Used often on turbo or supercharged engines which cram in extra air to help produce greater combustion. Obv if you push more air in you need more fuel or a greater efficiency of the said fuel to balance things up.. The water droplets are sprayed in to reduce hot spots which in turn reduces detonation, nothing to do with steam whatsoever..

 

[daleyd]

Nothing really to do with the oil, this is mainly an insignificant factor in most cases.

Problems are the design of the systems, particularly with the cheaper direct drive units as they are marginal at best; the real issue is air density, air is more dense in winter or when it is cold and the denser the air the more power it needs to compress it to a specific volume and pressure. In summer or when warm its density is reduced and normal service is resumed.

How does that work then? Once the oil has warmed then the compressors generally seem to work ok, all things being equal the ambient air will not have warmed up at all (your still sucking air in from the same place...) - if your theory was correct the compressor would still not run even when warm?

 

[rtbcomp]

In the 10 years I've been here I've never seen anyone complain of this problem with an oil-less compressor.

 

[rtbcomp]

... The water droplets are sprayed in to reduce hot spots which in turn reduces detonation, nothing to do with steam whatsoever..

The latent heat of vapourisation absorbed by the water reduces the temperature and the steam produced will increase the pressure in the cylinder.

 

[Noods]

Too prove it fill a cylinder with air and you will be able to rotate the flywheel by hand.. Now fill the same cylinder with H2O .. Water, you will not be able to turn the flywheel, and that's exactly the issue for the little compressors electric motor, trying to turn over whilst up against all that moisture ..

 

[rtbcomp]

^^ but put a few drops of water in, or water vapour and you will be able to turn it. Nobody's talking about filling the cylinder with water.

 

[rtbcomp]

Also, the air tends to be drier on cold frosty days and damp on warm humid ones. My compressor is fine on the muggy days, but fails on the cold dry days, so it's not moisture.

 

[brianblock]

surely the oil is just a splash bath principle so would it have that much effect

 

[WorkshopChris]

surely the oil is just a splash bath principle so would it have that much effect

Yes but its the cold sticky oil around the rings and cylinder bore that adds to the problem.
Its a common known problem, take a compressor that only just starts on a good day.
Add cold oil, thick grease in motor bearings, belts that don't want to flex. Then compound the problem with the fact that the grid supply voltage is often down on cold days, then add a possible extra load in home or workshop adding a little more volt drop.
This all adds to a motor that now draws just that little bit more and pops a fuse.
No one factor is big, they just all add up to take it past the edge.

 

[julianf]

Just FYI -

My compressor refused to start yesterday. Just a couple of turns, and then nothing - i flicked it off before any fuses were blown.

I drained all the air from the tank, and it started up fine. Whilst i was working, it cut in and out as usual.

I left it fully charged. Im sure that, if i went out and used a bit of air today, so it tried again to start on an (almost) full tank, it would be the same, and id have to drain the air again.

Fine in summer, and, as above, when its warm, so, with mine, its certainly temperature related.

 

[normspanners]

Is it that time of year so soon? my compressor wont start month, sometimes called november or december ?? some call it time to change compressor oil month,---- every year same posts getting tiring now, standard wording ---- I am running my compressor on a 1.5mm extension 100M ??long and it wont start,------ why?
LOOK AT THE MONTH !!!

Nothing really to do with the oil, this is mainly an insignificant factor in most cases.

It is 'ALL' about the oil, and is the main factor----------has been proved year after year time to go to new lower viscosity oil funny thing on saturday my standby tyre blower ( allways switched on 24/7) had tripped the amp switch and didnt start and was thinking I need to change the oil and thought I wonder when the first post would hit !

Think I have posted this once ---twice ---three --- or is it ten times ghttp://www.air-equipment.co.uk/air-compressors-and-cold-weather read 3rd paragraph

 

[WorkshopChris]

Is it that time of year so soon?

You know its a bad year when the compressor trips on a Monday morning and you have to go out to the compressor shed and defrost the unloaded valves with a hot air gun before it will start.

 

[rtbcomp]

Is it that time of year so soon? my compressor wont start month, sometimes called november or december ??...

Spring - they won't start because the motor cutouts fail due to excessive use during winter.

Summer - they overheat and seize up.

Autumn - they work fine, but it's too damp to do any spraying anyway.

 

[normspanners]

starting amps on the motor will be about 50 for a couple of seconds

BS has it right, thats in the summer but this time of year it can go for much longer especially on a 'throttling extension'
A normal 1.5mm will cause the volts dropping to sub 200 at the motor and the amps climbing uncontrollably .

IMO what is required is short 2.5mm lead to the motor at least and a 4mm Extension of if any decent length is req.
to minimise the volt drop.

Combustion engines use cooler air more efficiently with fuel droplets clinging on to the cool air..

what about a diesel then ? aint no fuel in the air, fact is cold air is more dense. therefore more compression.

HA one of the garages I do work for at has just bought a new compressor, WHY coz it wont start in the last few days, its running on an extension and NOW has bought a new 1ph !! unit again even though they have 3Ph in the place ?? well I did try to educate them but ??

 

[normspanners]

they won't start because the motor cutouts fail due to excessive use during winter.

HEHE Spring ---------Thats Capacitor or amp switch month! coz they are tired after the winter

 

[the snooper]

Nothing really to do with the oil, this is mainly an insignificant factor in most cases.

Problems are the design of the systems, particularly with the cheaper direct drive units as they are marginal at best; the real issue is air density, air is more dense in winter or when it is cold and the denser the air the more power it needs to compress it to a specific volume and pressure. In summer or when warm its density is reduced and normal service is resumed.

You're having a laugh surely? It's oil viscosity why do you think there are various grades ? Even cars need thinner oil below a certain temperature in winter, it's well documented on here about temperature problems in winter also warming the pump cures the problem

 

[brightspark]

+put it this way I used to run a 90cfm v twin compressor belt drive off a twin cylinder lister engine cranked by hand . in summer no problem cranking. in winter no chance . I had to warm the cylinders up along with warming the barrels on lister then it would crank ok always started with valves decompressed and tank open. not under pressure so that proves what's happening in a simple layman's language .cold weather thick oil = hard starting load . nothing to do with compression

 

[roofman]

Also i think it needs mentioned that any electric motor with a qouted HP rating direct off the shaft is never going to be as strong as via a pully and belt system for any compresser pump... Also it seems very ironic that its only the intregral units that seem to suffer the starting problems in the cold and not the belted machines with often pumps twice the size with the same size HP rated motor.

 

[rtbcomp]

My SIP's belt driven.