rustydollar
Silver Member
I'm going to power this compressor up with the 18 HP Perkins diesel that came from a Toro lawn mower, the compressor was a gift. It puts out 35 CFM and it's a two stage capable of 175 psi.
Air Comoressor on Diesel
- Thread starter rustydollar
- Start date
- Views: 3055
Stimw
Elite Member
Compressor/drive system is a process of calculations.
A lot of compressors use the same pump with different motors/engines.
The larger the drive HP the larger the drive pulley.
Everybody has seen a compressor that tries to stall out because someone put too small a power unit with too large a drive pulley!
Look up the pump/HP rating and it should give pulley size.
A lot of compressors use the same pump with different motors/engines.
The larger the drive HP the larger the drive pulley.
Everybody has seen a compressor that tries to stall out because someone put too small a power unit with too large a drive pulley!
Look up the pump/HP rating and it should give pulley size.
OP
rustydollar
Silver Member
The compressors rated RPM is 850 and it takes a minimum of 10 horsepower for a 35 cubic foot pump operating at 175 psi, my little Perkins is 18 hp so I'll adapt a drive pulley suitable to meeting the required operating rpm of the pump.
Pulley and RPM Calculator | Engineering Information - Culver Armature and Motor
hmmm...
Horsepower required to Compress Air
looks like about 3/16 hp/cfm @ 175 psi = 187 hp @ 35 cfm
Horsepower required to Compress Air
looks like about 3/16 hp/cfm @ 175 psi = 187 hp @ 35 cfm
jimmysisson
Veteran Member
- Joined
- Jul 11, 2005
- Messages
- 2,358
- Location
- W.Mass
- Tractor
- 1993 NH 2120 (the best), 1974 MF 135 (sold, but solid), 1947 Farmall A (bought, sold, bought back, sold again), 1956 MH50 lbt (sold, in 1980, darn it)
Groo, check your math...
Jim
Jim
Todd727
Gold Member
So, a fraction of a HP per CFM shouldn't result in a number of HP larger than the CFM. I only say this because many don't look at the numbers to see if they make sense when doing math.
aczlan
Good Morning
- Joined
- Mar 7, 2008
- Messages
- 16,985
- Tractor
- Kubota L3830GST, B7500HST, BX2660. Formerly: Case 480F LL, David Brown 880UE
I don't think that's right (either the formula or your calculation) as 105/16 (3/16*35) works out to a little over 6.5 horsepower and there is no way that can be right as a compressor that can put out 35CFM@175PSI is a beast and would have a much larger motor than a little 6.5HP one.
Aaron Z
CalG
Super Member
- Joined
- Sep 29, 2011
- Messages
- 5,832
- Location
- vermont
- Tractor
- Hurlimann 435, Fordson E27n, Bolens HT-23, Kubota B7200, Kubota B2601
That sounds like a great combination for an engine driven pump!
Why would anyone need 175 psi in any situation short of industrial I can not imagine.
120 psi fills all my shop needs and still I use caution around air wands and the like.
I suppose if one needed to optimize storage, the higher pressure would be welcome. Or if there were a certain application that needed the higher pressures.
From my experience with air equipment (aviation background) It is VOLUME at around 120psi that does the lions share of the work as far as hand tools and shop equipment goes.
Line losses are always an issue, and they can not be made up by running higher pump pressures "safely".
OP
rustydollar
Silver Member
Compressors build up heat, by using the twp stage unit I can have it set to cut out at 150 psi then coast along at idle speed, using a regulator set to draw air off at 90 psi from a 100 gallon storage tank gives me plenty of time between cycle times which allows for the compressor head to cool down.
any given pump requires a certain torque for any given PSI outlet
What I would do is figure the engine's peak torque, and set that with the pulley ratio to be a bit over the torque at the PSI you are looking for; then let the CFM lie where it may.
a diesel won't just keep slowing down and building more torque like a motor would.
What I would do is figure the engine's peak torque, and set that with the pulley ratio to be a bit over the torque at the PSI you are looking for; then let the CFM lie where it may.
a diesel won't just keep slowing down and building more torque like a motor would.
