I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

"stryped" wrote in message
...
I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

I have 3 hooked together and they cycle as demand increases or decreases.

On 2008-05-13, Tom Gardner wrote:

"stryped" wrote in message
...
I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

I have 3 hooked together and they cycle as demand increases or decreases.



They would need to be on different breakers.

i
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"stryped" wrote in message
...
I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

Boy, those sears horses are getting really small. 5hp on 110 and it only
gives you 6 cfm?

To answer your question, putting two together is a good idea for those heavy
use jobs. I gang my 7.5 two stage and the tractor PTO unit for sandblasting.

Karl

On 2008-05-14, Karl Townsend wrote:

"stryped" wrote in message
...
I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

Boy, those sears horses are getting really small. 5hp on 110 and it only
gives you 6 cfm?

Well ... given that 5HP on 110V would draw over 30A, and most
duplex wall outlets are fused for 15A, with some heavy duty ones fused
for 20A -- exactly how are you supposed to get 5HP out of a 110V outlet? :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"stryped" wrote in message
...
I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

yes, you can hook compressors in parallel.

but let me point something else out to you - your compressor is called 5 HP,
and puts out 6 cfm. I have a crafstman compressor (that I no longer use) -
it says "2 hp" and it puts out 7.2 CFM at the same PSI. What does that tell
you..... it tells you that you are not getting a real 5 HP compressor.
Moreover, at 750 watts per HP (minimum), 5 HP would be 3750 watts, which at
110V is 34 amps - I'll bet your compressor doesn't draw more than 20 amps.
So, Sears lied to you about the compressor.

I also have a 5 HP compressor, made by Quincy - it weighs about 850 pounds
and puts out 21 CFM at 160 PSI.

Moral - beware of high horsepower cheap compressors. What you really have
is a 1 hp compressor with an oversized motor. You will be happier if you
can find a surplus or used "real" compressor - look for a large compressor
with two pistons and a belt drive, look for a real 2HP motor - should draw
15 amps (for two HP) continuous at 110. Or if you can wire for 220, go to a
220V compressor - you will get a better unit and will be happier.


** Posted from http://www.teranews.com **

On May 13, 9:36*pm, "Karl Townsend"
wrote:
"stryped" wrote in message

...

I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

Boy, those sears horses are getting really small. 5hp on 110 and it only
gives you 6 cfm?

To answer your question, putting two together is a good idea for those heavy
use jobs. I gang my 7.5 two stage and the tractor PTO unit for sandblasting.

Karl

What is a tractor PTO unit? I dont knwo if I have seen on eof those?

On May 13, 6:14*pm, "Tom Gardner" wrote:
"stryped" wrote in message

...

I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

I have 3 hooked together and they cycle as demand increases or decreases.

What is the correct way to hook up more than one?

What is a tractor PTO unit? I don't know if I have seen one of those?

Simply an air compressor ran by the tractor. Make your own or buy one. If
you've got a tractor, its stupid to have a gasoline engine compressor unit.

My main use is for pruning.

Karl

"Karl Townsend" wrote in message
ews.com...
What is a tractor PTO unit? I don't know if I have seen one of those?

Simply an air compressor ran by the tractor. Make your own or buy one. If
you've got a tractor, its stupid to have a gasoline engine compressor
unit.

My main use is for pruning.

Karl



Karl
Did you build your own? I have an old Jeager compressor with a dead 4 cyl
Continental that I have been thinking about rigging to run with a PTO. I
would like to get the compressor to run at least 1000 to 1500 rpm. My Oliver
88 has a 550 rpm PTO and I have been looking for some sheaves to do this
with V belts or a 3-1 gearbox.
Steve

On Tue, 13 May 2008 14:06:35 -0700 (PDT), stryped
wrote:

I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90.

Break there. You have a "5 SEARS Horsepower" compressor. "Peak HP"
is not the same thing as actual HP - it's what the motor will put out
when so overloaded it's almost stalled, and right before it burns up.

For a 110-Volt model, if you do the math on the running amps it's
more likely a 1 real NEMA rated HP. You can't really get much more on
a 120V 20A receptacle circuit - 1 HP at 120V draws 16A, to get more
power you have to go to 240V and/or hard-wired units.

Here's a clue - when you find the HP Rating box on the motor maker's
nameplate is filled in with "SPL" - Special. They won't lie for the
marketing folks at Sears, so they leave it blank.

I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

Either one. If you hook two units together with a hard pipe make
sure they are roughly matched. You can NOT simply parallel the tanks
between a two-stage permanent compressor running 175 PSI in the tank
and a little portable that stops at 110 PSI - the two-stage will keep
running and pop off the safety valve on the portable.

You could parallel two units after the output pressure regulators,
and with check valves so the high pressure unit can't backfeed into
the receiver tank on the portable.

And remember that electric motors on compressors should not be
cycled on more than about five times an hour with a minimum 5 minute
running cycle, or you can burn up the motor - every start uses 'locked
rotor' current draw to start the motor, and it takes running for a
while to let the cooling fan draw that heat out of the windings. One
short cycle a day won't kill a motor, but dozens a day in rapid
succession sure will.

When sandblasting or doing other high air draw jobs it's better to
let the main compressor just keep running to keep up, don't start and
stop and force the compressor to short-cycle - do NOT wait for the
compressor to catch up and stop then start blasting again right away.
Much better to stop for a minute and watch the tank gauge, and when it
is approaching normal start blasting again and let the compressor stay
running...

This is why commercial units can be ordered with a constant-run
unloader system, just like a gasoline engine compressor. The motor
keeps running and stays cool while the compressor isn't working, and
the power draw is minimal (but not zero) with no work performed.

For factories this makes much more sense than stopping and starting
the motor several times an hour, with every start surge counting
against the KVA rate meter for the utility. (The higher the peak
power you use, the higher the KWH rate for the power.)

-- Bruce --

Bruce L. Bergman fired this volley in
:

On Tue, 13 May 2008 14:06:35 -0700 (PDT), stryped
wrote:

I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90.

Break there. You have a "5 SEARS Horsepower" compressor. "Peak HP"
is not the same thing as actual HP - it's what the motor will put out
when so overloaded it's almost stalled, and right before it burns up.


Yeah... A friend gave me a fairly new Huskey 5HP (110v) job because "It
runs slow".

I peeled off the covers to discover a interestingly built pump (which I
saved for other things) and a motor no larger than my fist. This thing
was wound with only a few dozen turns of about #16 wire, had less metal
in it than a good syncronous clock motor, and had one lobe of the
armature completely shorted.

He had about ten total hours of USE on the compressor... probably 30-40
minutes of run-time.

These things are more junky than cheap vacuum cleaners.

Now... the 26-gallon tank on wheels with a "space saving" stand-up
feature made a dandy portable air tank. I actually have a large enough
porta-air now to get my tractor limping back out of the pasture if I get
a flat. G

LLoyd

5 real horsepower would be at least 46 amps on 115v, power factor and
all, included. I have seen, installed and sold several such motors and
never saw one that was for 115 volts, only for 230.

The Bador website does not list any either.

The venerable Baldor L1408T, which is 3 HP, uses 32 amps. The 5 HP
equivalent of that would be 32*5/3=53 amps.

i

On Wed, 14 May 2008 06:28:32 -0700 (PDT) in rec.crafts.metalworking,
stryped wrote,
What is the correct way to hook up more than one?

A Tee fitting.

Did you build your own? I have an old Jeager compressor with a dead 4 cyl
Continental that I have been thinking about rigging to run with a PTO. I
would like to get the compressor to run at least 1000 to 1500 rpm.

Ayup. Just use a double pulley and belt. Step it up 4:1 so you can leave the
tractor just a crack over idle. A 100# LP tank makes a great air bladder.

Karl

"Karl Townsend" wrote in message
anews.com...

Did you build your own? I have an old Jeager compressor with a dead 4 cyl
Continental that I have been thinking about rigging to run with a PTO. I
would like to get the compressor to run at least 1000 to 1500 rpm.

Ayup. Just use a double pulley and belt. Step it up 4:1 so you can leave
the tractor just a crack over idle. A 100# LP tank makes a great air
bladder.

Karl


This one is still in the trailer. The tank, controls even a jack hammer is
still there.
Steve

stryped wrote,
What is the correct way to hook up more than one?

My pieced-together smaller compressor has one female quick disconnect
directly from the tank and a second one after the regulator. I made
this pipe cross adapter to connect it to another larger compressor or
a portable tank;

O O is pressure gauge #4
--+--X-- female QD #3, + cross, X valve, male QD #2
v v male QD #1

A cross is like a tee but with four legs. You could use a tee and omit
the gauge.

Close the valve and plug QD#1 into the tank of the smaller compressor.
Plug an air hose from the larger compressor into QD#2 and open the
valve to connect them. Close the valve before unplugging.

The portable tank has a female QD in the outlet. Plug QD#1 into it to
fill and use the tank. Fill from QD#2, draw air from #3.

The highest pressure shutoff setting in the system has to be less than
the lowest safety blowoff valve. On mine the large compressor shuts
off at 120PSI, the smaller one's relief opens at 125, which is
probably too close.

The small one has a true 1/2HP motor belted to draw 8-9A at shutoff. I
can sandblast continuously with it at 50PSI, using the large
compressor's tank as a reservoir (the large one runs but needs more
work). The pressure slowly drops while blasting and recovers to ~60PSI
while I fill the cup.

This is an updated rehash of my first RCM discussion with Fitch about
15 years ago.

Jim Wilkins

PTO = Power Take Off.

It is a spline rod sticking out the back end of the tractor
and from the massive transmission. With the tractor at full stop and
brakes on, one can attach the pto to another unit and when the PTO rotates
it does something.

PTO's often turn blades or rotating things. Mowers and ....

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


stryped wrote:
On May 13, 9:36 pm, "Karl Townsend"
wrote:
"stryped" wrote in message

...

I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?
Boy, those sears horses are getting really small. 5hp on 110 and it only
gives you 6 cfm?

To answer your question, putting two together is a good idea for those heavy
use jobs. I gang my 7.5 two stage and the tractor PTO unit for sandblasting.

Karl

What is a tractor PTO unit? I dont knwo if I have seen on eof those?


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"stryped" wrote in message
...
On May 13, 6:14 pm, "Tom Gardner" wrote:
"stryped" wrote in message

...

I have a Craftsman 30 gallon 5 horsepower 110 volt air compressor. It
puts out 6 cfm at 90. I would like to be able to paint and do more
such as sandblast. Could I get another similar sized compressor and
hook the both togther or do I have to break down and just buy an
expensive bigger compressor?

I have 3 hooked together and they cycle as demand increases or decreases.

What is the correct way to hook up more than one?
*********************************************

Mine all just connect to the main 1" pipe that feed the whole shop. They all
have ball valves on their output. One has it's pressure switch at 65 low/110
high, one set at 70/110, one at 80/110. (if I remember correctly, it's been
years) If #3 kicks in, we're using a LOT of air. 90% of the time only one
compressor is running.

In article ,
"Tom Gardner" wrote:

Mine all just connect to the main 1" pipe that feed the whole shop. They all
have ball valves on their output. One has it's pressure switch at 65 low/110
high, one set at 70/110, one at 80/110. (if I remember correctly, it's been
years) If #3 kicks in, we're using a LOT of air. 90% of the time only one
compressor is running.

You probably should shift the setpoints around every year or so, if the
compressors are similar, to balance the runtime (logic changes if they
are different sizes.)

--
Cats, coffee, chocolate...vices to live by

"Ecnerwal" wrote in message
...
In article ,
"Tom Gardner" wrote:

Mine all just connect to the main 1" pipe that feed the whole shop. They all
have ball valves on their output. One has it's pressure switch at 65 low/110
high, one set at 70/110, one at 80/110. (if I remember correctly, it's been
years) If #3 kicks in, we're using a LOT of air. 90% of the time only one
compressor is running.

You probably should shift the setpoints around every year or so, if the
compressors are similar, to balance the runtime (logic changes if they
are different sizes.)

--
Cats, coffee, chocolate...vices to live by

They're Quincys, I'm not sure where they ARE anymore...probably should change
the oil! (kidding!)

On Thu, 15 May 2008 11:52:46 -0400, "Tom Gardner"
wrote:
"Ecnerwal" wrote in message
...
In article ,
"Tom Gardner" wrote:

Mine all just connect to the main 1" pipe that feed the whole shop. They all
have ball valves on their output. One has it's pressure switch at 65 low/110
high, one set at 70/110, one at 80/110. (if I remember correctly, it's been
years) If #3 kicks in, we're using a LOT of air. 90% of the time only one
compressor is running.

You probably should shift the setpoints around every year or so, if the
compressors are similar, to balance the runtime (logic changes if they
are different sizes.)

They're Quincys, I'm not sure where they ARE anymore...probably should change
the oil! (kidding!)

Use some air, then shut everything else down and follow the low
thumping sound. You'll find it back in the corner.

I wouldn't shift the setpoints, but if they all have magnetic
starters consider wiring in a triplexer between all the pressure
switches and starter coils to rotate the running order - first call
starts them 1 - 2 - 3, second call goes 2 - 3 - 1...

And if they are all big piston units, when one dies look into a
constant-run screw compressor with a VFD for the 'main unit' and save
the piston jobs for backup. Will help your demand charge a Lot just
by eliminating all the start surges.

-- Bruce --