Air Compressor - Supe'ing Up Question
Angello Huong
compressor that I've supe'ed up.
The pump normally turns on at 80 PSI and then shuts off at 115 PSI.
Problem is, at 80 PSI (before it turns on again), my nail guns don't
drive the nails flush. I need it to have a consistent minimum 100 PSI
going through it.
I have increased the pressure switch so that it now goes from 100
PSI cut-on and then 135 PSI shut off. I know that it will likely
reduce the life of my compressor in the long run, but does anyone know
how much difference a 20% increase in pressure reduces the working
life of a pump? I only use it for a few hours a year, so the
compressor doesn't get a lot of regular stress put on it. Plus, it's
not too expensive, so I can just buy another one. So this is more of
an educational question.
I've heard that all 2 HP (and up) pumps (single and 2 stage) are
capable to doing more than 115 PSI. Maybe the 2 stage can do it with
more CFM and with a longer pump life.
Also, I'm thinking about connecting it in series with a separate 10
gal. air tank, so that I can have a total working capacity of 18 gal
combined.
Is this too abusive to be doing to my poor 2 HP motor? In theory,
if I let it have several minutes of rest and cool-downs between engine
cycles, it should be ok, right?
Angello
Tony Hwang
Safety first! I double your motor isreal 2 HP rated.
Bob F
You
Hustlin' Hank
> � I have a single-stage 2 HP, 8 gallon Central Pneumatic air
You'll probably be ok. But, the first consideration is the tank not
holding up under the higher pressure. Is it rated for 135 psi? If not,
it may blow! LOL
Also, Tanks build up moisture and begin to rust on the inside. When
the rust is bad enough it will leak and maybe explode.
Since your compressor will be running longer to build up more
pressure, you wil undoubtedly create more heat for a longer period of
time. Who knows how that heat will affect the seals, gaskets and etc.?
More load on the motor will also create more heat on the motor. Again,
who knows how the bearings, windings will hold up?
Attaching an extra tank will only make the compressor run longer which
means it will be subjected to longer periods of heat. But, it will
give more capacity.
Bottom line: All this doesn't matter since you are ready to buy a new
when it burns up because they are so cheap anyway.
roflmao
Hank
sa...@dog.com
Beat it until it quits and then buy the bigger compressor that you
should have bought in the first place. Next time buy one bigger than
you think you will need and grow into it.
BQ340
Also check your air hose. Small diameter hose & using restrictive
fittings will cause that problem.
MikeB
Joe
Second that motion. Get a set of Milton V fittings for your hoses and
you'll nearly double air flow.
Joe
Roger Shoaf
<gfre...@aol.com> wrote in message
news:315lh55q53hb9m3bc...@4ax.com...
>
> The load
> on the motor is actually less at 135 PSI than it is at 100. This is
> because the compressor is not moving as much air. That sounds counter
> intuitive but if you put an amp meter on it you will see.
I do not think this can be true. If you increase the work, you will
increase the load.
--
__
Roger Shoaf
Important factors in selecting a mate:
1] Depth of gene pool
2] Position on the food chain.
Hustlin' Hank
> <gfretw...@aol.com> wrote in message
>
> news:315lh55q53hb9m3bc...@4ax.com...
>
>
>
> > �The load
> > on the motor is actually less at 135 PSI than it is at 100. This is
> > because the compressor is not moving as much air. �That sounds counter
> > intuitive but if you put an amp meter on it you will see.
>
> I do not think this can be true. �If you increase the work, you will
> increase the load.
>
> --
>
> __
> Roger Shoaf
I agree Roger. Which also means an increase in heat at compressor AND
motor AND current draw.
Hank
tra...@optonline.net
>
> - Show quoted text -
And I agree with you guys too. Anyone who's used a bicycle pump
knows that while you are moving less volume of air at higher pressure,
it takes a hell of a lot more work.
As to the original question, I wouldn't worry so much about the
additional work load on the compressor from setting the kick in a
little higher, especially since it's only used a few hours a year,
Lp1331 1p1331
gun and a trim gun, but haven't used the trim one yet. I love it, and
would never go back to an air operated gun. Larry
Stormin Mormon
And then let the relief valve do its thing when the pressure
is too high. I would also think of adding a cooling fan.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Angello Huong" <angell...@hotmail.com> wrote in message
news:qnmjh5d1pa6nco9bq...@4ax.com...
I have a single-stage 2 HP, 8 gallon Central Pneumatic air
compressor that I've supe'ed up.
The pump normally turns on at 80 PSI and then shuts off at
115 PSI.
Problem is, at 80 PSI (before it turns on again), my nail
guns don't
drive the nails flush. I need it to have a consistent
minimum 100 PSI
going through it.
Angello
Stormin Mormon
pressure. I doubt that anyone will find higher discharge
pressure resulting in lower amperage. I may try it some day
with my little pancake compressor.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Roger Shoaf" <sh...@nospamsyix.com> wrote in message
news:12600434...@news01.syix.com...
cl...@snyder.on.ca
Good advice, but the nail gun doesn't use much VOLUME of air. It DOES
require good pressure. Stting the cut-in pressure higher solves that
problem, but makes it cycle oftener. Boosting the cut-out pressure
reduces the cycling. The extra wear caused by the higher pressure will
be partly offset by the reduction in stress from cycling, so over-all
the life of both the pump and motor is unlikely to be affected a great
deal by changing the settings. A larger tank will cause slightly
longer (startup) run-times, but at the same CFM consumption the
overall run time should not be affected.
cl...@snyder.on.ca
<sh...@nospamsyix.com> wrote:
>
><gfre...@aol.com> wrote in message
>news:315lh55q53hb9m3bc...@4ax.com...
>>
>> The load
>> on the motor is actually less at 135 PSI than it is at 100. This is
>> because the compressor is not moving as much air. That sounds counter
>> intuitive but if you put an amp meter on it you will see.
>
>I do not think this can be true. If you increase the work, you will
>increase the load.
But ARE you increasing the "work"? If the flow drops off faster than
the pressure rizes, the actual WORK is reduced. Not saying this
happens on this compressor
Hustlin' Hank
> On Sat, 05 Dec 2009 21:31:24 -0500, cl...@snyder.on.ca wrote:
> >On Sat, 5 Dec 2009 12:03:42 -0800, "Roger Shoaf"
> ><sh...@nospamsyix.com> wrote:
>
> >>news:315lh55q53hb9m3bc...@4ax.com...
>
> >>> �The load
> >>> on the motor is actually less at 135 PSI than it is at 100. This is
> >>> because the compressor is not moving as much air. �That sounds counter
> >>> intuitive but if you put an amp meter on it you will see.
>
> >>I do not think this can be true. �If you increase the work, you will
> >>increase the load.
>
> >But ARE you increasing the "work"? If the flow drops off faster than
> >the pressure rizes, the actual WORK is reduced. Not saying this
> >happens on this compressor
>
> compressor loses efficiency at higher pressure. Air compressors are
> not HVAC compressors or bicycle pumps.
> It is just like putting your hand over a vacuum cleaner hose, the
> motor speeds up.
> If you really want to see this I will shoot some pictures of my
> compressor gauge at several pressures with the clamp on ammeter in the
> shot. I was surprised too, until someone explained it to me. The
> highest current is drawn at around 90-100 PSI on a compressor that
> shuts off around 150. It is a bell curve.-
But the compressor/vacuum/outboard boat motor isn't working or
producing anything or as much as it should. Therefore being less
efficient. Another analogy is the outboard boat motor or centrifical
pump. Cavitation will cause the motors to increase in RPM but the pump
isn't pumping any liquid and the boat motor isn't pushing the boat.
Basically, If the amps are decreasing, less work is getting done. Less
work will equal less heat, but heat will still build as the result of
friction.
Hank
Bob F
Or, a larger tank would let it cycle the same with a reduced high pressure.
Bob F
> compressor loses efficiency at higher pressure. Air compressors are
> not HVAC compressors or bicycle pumps.
> It is just like putting your hand over a vacuum cleaner hose, the
> motor speeds up.
> If you really want to see this I will shoot some pictures of my
> compressor gauge at several pressures with the clamp on ammeter in the
> shot. I was surprised too, until someone explained it to me. The
> highest current is drawn at around 90-100 PSI on a compressor that
> shuts off around 150. It is a bell curve.
Do it. I'd love to see the result.
Roger Shoaf
<gfre...@aol.com> wrote in message
news:kbhmh51bimdgr0lt1...@4ax.com...
> compressor loses efficiency at higher pressure. Air compressors are
> not HVAC compressors or bicycle pumps.
> It is just like putting your hand over a vacuum cleaner hose, the
> motor speeds up.
> If you really want to see this I will shoot some pictures of my
> compressor gauge at several pressures with the clamp on ammeter in the
> shot. I was surprised too, until someone explained it to me. The
> highest current is drawn at around 90-100 PSI on a compressor that
> shuts off around 150. It is a bell curve.
I don't think you are correct. If the motor is driving the compressor to
compress air at a higher pressure, it will require more power than
compressing air to a lower pressure. You can't escape the physics.
--
Roger Shoaf
About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.
Roger Shoaf
<gfre...@aol.com> wrote in message
news:kbhmh51bimdgr0lt1...@4ax.com...
> On Sat, 05 Dec 2009 21:31:24 -0500, cl...@snyder.on.ca wrote:
> Air compressors are
> not HVAC compressors or bicycle pumps.
Actually they are all very similar. An HVAC compressor just compresses the
vapor that is presented at the inlet valve, if you were to open the inlet
valve to the atmosphere it would compress the air just like a bicycle pump
or an air compressor. The differences come in to the design of how they are
powered and how they are cooled, but they all do the same thing.
Ed Pawlowski
>> compressor loses efficiency at higher pressure. Air compressors are
>> not HVAC compressors or bicycle pumps.
>> It is just like putting your hand over a vacuum cleaner hose, the
>> motor speeds up.
>> If you really want to see this I will shoot some pictures of my
>> compressor gauge at several pressures with the clamp on ammeter in the
>> shot. I was surprised too, until someone explained it to me. The
>> highest current is drawn at around 90-100 PSI on a compressor that
>> shuts off around 150. It is a bell curve.
>
> I don't think you are correct. If the motor is driving the compressor to
> compress air at a higher pressure, it will require more power than
> compressing air to a lower pressure. You can't escape the physics.
>
> --
>
> Roger Shoaf
It may be how the particular compressor is working. You are correct that it
takes a certain amount of energy to compress the air. The compressor,
however, may react differently by drawing less amps, but for a longer time.
It may be less efficient due to blow by of the piston too.
bud--
> On Sun, 6 Dec 2009 12:21:43 -0800, "Roger Shoaf"
> how it works. I will get some pictures tomorrow.
It is counter-intuitive. Real interesting.
Power is basically pressure times flow rate. As Clare wrote, if flow
drops faster than pressure rises the power goes down. With a piston pump
the flow rate would seem to be the same. But the piston does not contact
the head. At high pressure there is more air left in the cylinder
between the piston and the head, so the flow rate is lower. Wouldn't be
surprised if this is an intentional design with more space than needed.
-----------------------
A separate issue - with a higher start pressure the compressor starts
against a higher head pressure which makes it harder to start the motor
which produces more motor heating when starting. Or are these things
unloaded to start?
As others have said, the motor also operates on a shorter cycle with
more starts which can be a major problem. I would guess motor heating is
the limiting factor.
--
bud--
jamesgangnc
> gfretw...@aol.com wrote:
> > On Sun, 6 Dec 2009 12:21:43 -0800, "Roger Shoaf"
> > <sh...@nospamsyix.com> wrote:
>
> >>news:kbhmh51bimdgr0lt1...@4ax.com...
> >>> On Sat, 05 Dec 2009 21:31:24 -0500, cl...@snyder.on.ca wrote:
>
> >>>> On Sat, 5 Dec 2009 12:03:42 -0800, "Roger Shoaf"
> >>>> <sh...@nospamsyix.com> wrote:
>
>
> - Show quoted text -
air compressors are unloaded at the end of a run cycle. That's what
that short pssst you get at the end is, unloading the line form the
compressor to the tank.
cl...@snyder.on.ca
wrote:
They are DEFINITELY unloaded to start. No way a standard compressor
duty motor could start a normal compressor head against even FIFTY
pounds of pressure.
Roger Shoaf
"bud--" <remove....@isp.com> wrote in message
news:8ccb4$4b1d2a09$cde8d5ac$29...@DIALUPUSA.NET...
>
> It is counter-intuitive. Real interesting.
>
> Power is basically pressure times flow rate. As Clare wrote, if flow
> drops faster than pressure rises the power goes down. With a piston pump
> the flow rate would seem to be the same. But the piston does not contact
> the head. At high pressure there is more air left in the cylinder
> between the piston and the head, so the flow rate is lower. Wouldn't be
> surprised if this is an intentional design with more space than needed.
>
I think you are a bit confused. As the piston goes up, the pressure
increases until the pressure in the cylinder is greater than the pressure on
the other side of the discharge valve. High pressure air now flows until
the pressure is equal and the discharge line closes. (This occurs when the
piston is at top dead center)
At top dead center in the space between the valve and the piston, there is a
volume of air. As the piston goes down, that volume of air decompresses,
and the intake valve will open when the pressure inside the cylinder is less
than the pressure. when the piston is at the bottom of the stroke, the valve
shuts and the pressure inside the cylinder is equal to the air pressure
outside the compressor.
Now the work begins. There are two extreme conditions one where the tank is
empty, or equal to atmospheric pressure, and the other extreme is where the
tank is "full". "Full" is used here to describe a condition where the
pressure inside the cylinder when the piston is at top dead center is equal
to the tank pressure. The valve can not open and the pressure will not rise
as no air is being added.
Consider the full condition situation. Energy is required to compress all
of the air in the cylinder even though none of the air that is compressed
moves into the tank. After the piston begins it's descent, the air pressure
helps push down the piston requiring less energy to be applied by the motor.
Now consider the empty condition. The air pressure at the bottom of the
stroke equals the atmospheric pressure. The piston goes up, and so does the
pressure inside the cylinder so the discharge valve opens and the air flows
to the tank.
If we were to have a hole in the tank that would allow all of the air pumped
into the tank to escape while the piston was going down, each cycle of the
compressor would consume the same amount of power.
The same thing is true when the "full" condition exists, each cycle of the
compressor would consume the same amount of power.
The power consumption at "full" is more than the power consumption at empty.
If you were to add a third condition of "half full", the piston starts at
the same condition, but as it goes up the pressure rises inside the cylinder
until the cylinder pressure exceeds the pressure in the tank and the valve
opens to the tank. If a hole smaller than the one in the empty condition,
but just large enough to bleed off all the increase in pressure that you
gained on the previous cycle you would consume more energy than at the empty
condition than you would at the "full" condition.
At all three conditions described no energy was being expended at the end pf
the compressor hose, yet power was being used to one degree or another and
the power was used to create heat. (Waste)
The temperature of the compressed air increases with the pressure. and that
heat is transferred to the walls of the compressor and dissipated outside of
the compressor. Since the air inside the compressor will be at the highest
pressure at the "full" condition it will be hotter than it would be at "half
full" or empty conditions. Since the rate of heat transferred increases
with the difference in temperature more energy has to be consumed at the
"full" condition than anything less than "full".
So what would explain this:
"As for your motor, upping the pressure won't hurt it a bit. The load
on the motor is actually less at 135 PSI than it is at 100. This is
because the compressor is not moving as much air. That sounds counter
intuitive but if you put an amp meter on it you will see."
observation? I think what explains this is that his amp meter has some lag.
The measurement was taken from an inductive load which is quite dynamic.
Magnetic fields are being created and collapsing as the motor turns and as
the incoming power alternated from positive to negative and back to
positive.
To measure the load it would be better to use a Watt meter.
Consider the full condition once more. The air is compressed and the piston
starts to go down, The energy in the air is being expended as heat as long
as it is hotter than the compressor and it is expanding pushing the piston
down. Since some energy is expended as heat and some is gained as heat (you
will have a net loss) some energy is being sent back to the motor as during
the down stroke the piston is actually pushing the motor a bit, making the
motor an alternator, and sending current backwards. So it depends where
exactly in the compressor cycle you capture the measurement of the electrons
flowing.
Upon the completion of the compressor cycle you will have a net flow of
Watts from the power grid to the motor even though you may have some points
in time during the cycle when the flow is actually reversed.
Hope this helps.
cl...@snyder.on.ca
<sh...@nospamsyix.com> wrote:
>
>"bud--" <remove....@isp.com> wrote in message
>news:8ccb4$4b1d2a09$cde8d5ac$29...@DIALUPUSA.NET...
>>
>> It is counter-intuitive. Real interesting.
>>
>> Power is basically pressure times flow rate. As Clare wrote, if flow
>> drops faster than pressure rises the power goes down. With a piston pump
>> the flow rate would seem to be the same. But the piston does not contact
>> the head. At high pressure there is more air left in the cylinder
>> between the piston and the head, so the flow rate is lower. Wouldn't be
>> surprised if this is an intentional design with more space than needed.
>>
>
>I think you are a bit confused. As the piston goes up, the pressure
>increases until the pressure in the cylinder is greater than the pressure on
>the other side of the discharge valve. High pressure air now flows until
>the pressure is equal and the discharge line closes. (This occurs when the
>piston is at top dead center)
If the air is compressed and does NOT flow out the "exhaust" valve the
pressure pushes the piston back down. On a single cyl or parallel cyl
compressor this does not do anything, but on an opposed or V or
alternate twin, this reduces the amount of power required to turn the
compressor.
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
<gfre...@aol.com> wrote in message
news:sss2i55ln7mqeajv2...@4ax.com...
Here you go
http://gfretwell.com/electrical/compressor%20amps.jpg
short answer
14.3a @ 80 psi
16.1a @ 110 psi
13.2 a @ 150psi
cl...@snyder.on.ca
<cayoung61**spamblock##@hotmail.com> wrote:
>Mine just went up, watts went up with pressure.
You didn't go highg enough, perhaps???
Not ALL compressors exhibit this counterintuitive behaviour, but a
surprising percentage most likely will.
JIMMIE
> On Thu, 10 Dec 2009 17:56:46 -0500, "Stormin Mormon"
>
> >Mine just went up, watts went up with pressure.
>
> You didn't go highg enough, perhaps???
>
> Not ALL compressors exhibit this counterintuitive behaviour, but a
> surprising percentage most likely will.
I noticed this a while back I think it is because the cheaper
compressor have crappy motors. I tore one apart that burned up and it
tlooked like it had half the wire it should in it.
Jimmie
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
<cl...@snyder.on.ca> wrote in message
news:9d53i55bs5olcg1o1...@4ax.com...
On Thu, 10 Dec 2009 17:56:46 -0500, "Stormin Mormon"
You didn't go highg enough, perhaps???
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
<gfre...@aol.com> wrote in message
news:f563i59g0i2ngg9je...@4ax.com...
On Thu, 10 Dec 2009 17:56:46 -0500, "Stormin Mormon"
<cayoung61**spamblock##@hotmail.com> wrote:
>Mine just went up, watts went up with pressure.
110 PSI seems to be the break point.
Bob F
> On Tue, 8 Dec 2009 12:30:25 -0800, "Roger Shoaf"
>> I think you are a bit confused. As the piston goes up, the pressure
>> increases until the pressure in the cylinder is greater than the
>> pressure on the other side of the discharge valve. High pressure
>> air now flows until the pressure is equal and the discharge line
>> closes. (This occurs when the piston is at top dead center)
>
> If the air is compressed and does NOT flow out the "exhaust" valve the
> pressure pushes the piston back down. On a single cyl or parallel cyl
> compressor this does not do anything, but on an opposed or V or
> alternate twin, this reduces the amount of power required to turn the
> compressor.
On a single cylinder compressor it does do something. It pushes the piston down,
speeding up the motor, reducing the current drawn.