This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
The Forum Parts and Services Unofficial Allis Store Tractor Shows Serial Numbers History
Forum Home Forum Home > Other Topics > Shops, Barns, Varmints, and Trucks
  New Posts New Posts
  FAQ FAQ  Forum Search   Events   Register Register  Login Login


OK,,for the mathematicians here,,,,

 Post Reply Post Reply
Author
Message
desertjoe View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 23 Sep 2013
Location: New mexico
Points: 13696
Post Options Post Options   Thanks (0) Thanks(0)   Quote desertjoe Quote  Post ReplyReply Direct Link To This Post Topic: OK,,for the mathematicians here,,,,
    Posted: 09 Nov 2019 at 7:12pm

 OK,,,for some time,,the motor on my air compressor has been on the going south trip,,so,I went to look at a job in a guys garage and he gots two motors I would like to buy or trade for this work. Mine is a 3 HP 1750 1 phase 220 volt capacitor start and capacitor run that has been on the compressor forever,,,,Pully size on the motor is 5 1/2"
  He has a 3 HP 1750 1 phase that would be almost a direct changeout.
 He also has what I would really like to have and is a 5HP 3600 1 phase 220 volt.
 The compressor has a 14" flywheel, so that is not changeable. What size pulley would I have to run on the motor to slow it down to where the 1750 is running now,,?
Back to Top
Sponsored Links


Back to Top
DMiller View Drop Down
Orange Level Access
Orange Level Access


Joined: 14 Sep 2009
Location: Hermann, Mo
Points: 33992
Post Options Post Options   Thanks (0) Thanks(0)   Quote DMiller Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 7:55pm
Basically Half the Speed on your Motor, to get the travel distance of the belts Close, would need to be 2"(1.95) by Pi R squared calculation. Get the running Diam of the 5.5 then reduce by Half, reverse the math.

Back to Top
LouSWPA View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: Clinton, Pa
Points: 25153
Post Options Post Options   Thanks (0) Thanks(0)   Quote LouSWPA Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 8:13pm
2-3 inches, as DM says. close enough anyhow
I am still confident of this;
I will see the goodness of the Lord in the land of the living.
Wait for the Lord;
be strong and take heart and wait for the Lord. Ps 27
Back to Top
Michael V (NM) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 12 Sep 2009
Location: NM
Points: 2472
Post Options Post Options   Thanks (0) Thanks(0)   Quote Michael V (NM) Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 8:13pm
Would it hurt to run the compressor faster??...it would really get them CFM up there Where ya could some big air tools....

I have a kinda home built compressor with a Champion compressor, it has a 3 hp on it since I've had it, the book says a 7 hp motor will get more rpm on the compressor, which = more CFM,
it's just that its at the max that the 3 hp can do...
oh yea,, it's a 2 stage and takes some hp to pull it..
Back to Top
Hubert (Ga)engine7 View Drop Down
Orange Level
Orange Level
Avatar

Joined: 12 Sep 2009
Location: Jackson Cnty,GA
Points: 6468
Post Options Post Options   Thanks (0) Thanks(0)   Quote Hubert (Ga)engine7 Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 8:13pm
A 2 3/4 inch pulley should get you about the same rpm's on the flywheel. I would stay with the 3hp motor though if the existing one has had adequate power, it will require less current to operate.
Just an old country boy saved by the grace of God.
Back to Top
Hubert (Ga)engine7 View Drop Down
Orange Level
Orange Level
Avatar

Joined: 12 Sep 2009
Location: Jackson Cnty,GA
Points: 6468
Post Options Post Options   Thanks (0) Thanks(0)   Quote Hubert (Ga)engine7 Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 8:20pm
Dave, down here pi R round, not square. LOL By using pi times the radius squared will give you the area of the circle, pi times the diameter gives the circumference which will be roughly the distance the belt moves in one revolution.
Just an old country boy saved by the grace of God.
Back to Top
Hubert (Ga)engine7 View Drop Down
Orange Level
Orange Level
Avatar

Joined: 12 Sep 2009
Location: Jackson Cnty,GA
Points: 6468
Post Options Post Options   Thanks (0) Thanks(0)   Quote Hubert (Ga)engine7 Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 8:22pm
Had to go dig out my trusty slide rule to figure all of that. We didn't have hand held calculators when I was in school.
Just an old country boy saved by the grace of God.
Back to Top
desertjoe View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 23 Sep 2013
Location: New mexico
Points: 13696
Post Options Post Options   Thanks (0) Thanks(0)   Quote desertjoe Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 9:14pm


 Well Chit I KNEW I shoulda told all the tidbits on the first go round,,,,Wink Ya'll see tmy shop compressor is an AO Smith V4 SINGLE stage that makes a whole lot of air,,,just not at very high pressures like a two stage would but so far the pressure  it does make 90# has been plenty for my air tools as well as my homemade bead blaster. I don't remember exactly the scfm it does make, (like in the neighborhood of 20 scfm) haS been enough for what I need.
 Michael,,,you do got a point in that I prolly should drive the AO Smith compressor a shade faster for faster pressure build up as it now just loafs along at the speed it now runs at with the existing 3 HP.
  BUT,,I do have a two stage Champion compressor that I traded work for and I completely rebuilt it for a spare and it been under the work bench for bout 5 years. It has a 5" low stage cylinder and a 2" high stage cylinder. The PO of the 2 stage had it driven with a 5 HP 3600  motor with a really small pulley on the motor but I did not measure the pulley back then.
 What I would like to do is buy that guy's 5 HP motor and install it on the AO Smith and run it till the compressor crashes ,,then install the rebuilt Champion with the 5 HP already there,,,,sound like a plan,,,??? ClapClap
Back to Top
shameless dude View Drop Down
Orange Level
Orange Level
Avatar

Joined: 10 Apr 2017
Location: east NE
Points: 13607
Post Options Post Options   Thanks (0) Thanks(0)   Quote shameless dude Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 9:39pm
whew...
Back to Top
LouSWPA View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: Clinton, Pa
Points: 25153
Post Options Post Options   Thanks (0) Thanks(0)   Quote LouSWPA Quote  Post ReplyReply Direct Link To This Post Posted: 09 Nov 2019 at 11:44pm
Originally posted by Hubert (Ga)engine7 Hubert (Ga)engine7 wrote:

Dave, down here pi R round, not square. LOL By using pi times the radius squared will give you the area of the circle, pi times the diameter gives the circumference which will be roughly the distance the belt moves in one revolution.


Hubert, I cant tell you how many times that line got me ejected from math class.....but it made Debby Cook, the little blond that sat next to me in math class laugh every time..... so I was doomed to repeat it, and get ejected!

side not, I saw Debby ten years ago at out 40th class reunion.....she sure held up well!
I am still confident of this;
I will see the goodness of the Lord in the land of the living.
Wait for the Lord;
be strong and take heart and wait for the Lord. Ps 27
Back to Top
Coke-in-MN View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 12 Sep 2009
Location: Afton MN
Points: 41980
Post Options Post Options   Thanks (0) Thanks(0)   Quote Coke-in-MN Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 12:47am
You figure about 1/2 the diameter but then need to check the amp draw of motor when running . I went to a larger motor on mine from 2 to 3 hp but at 1750 RPM , took amp reading on motor and then increased drive pulley by about 3/4 " over 2 HP motor . 
 Later i changed out compressor head and new one had larger driven pulley so had to do another amp draw for load to get size right . 
 Most capacitor start , capacitor run have the small 5/8 shaft where larger and heavier motors with have a large shaft I believe 1 1/8 or 1 1/4 .

Edited by Coke-in-MN - 10 Nov 2019 at 12:48am
Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel.
Back to Top
DMiller View Drop Down
Orange Level Access
Orange Level Access


Joined: 14 Sep 2009
Location: Hermann, Mo
Points: 33992
Post Options Post Options   Thanks (0) Thanks(0)   Quote DMiller Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 5:26am
I can agree Hubert, PiE R Round, but Pi R Squared too!! I LOVE Pie, square pie, round pie, triangle pie, any kind of Pie!!
Back to Top
Tbone95 View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 31 Aug 2012
Location: Michigan
Points: 12185
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tbone95 Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 6:14am
When figuring ratios, Pi R constant. As in, on both sides of the equation, so simply ratio the diameters. And account for the different motor RPM of course.
Back to Top
chaskaduo View Drop Down
Orange Level
Orange Level
Avatar

Joined: 26 Nov 2016
Location: Twin Cities
Points: 5200
Post Options Post Options   Thanks (0) Thanks(0)   Quote chaskaduo Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 6:32am
Here's a pulley size calculator I use that has a few different scenarios use can throw at it. Been really helpful, and easy peezy is what I like.
 
1938 B, 79 Dynamark 11/36 6spd, 95 Weed-Eater 16hp, 2010 Bolens 14hp
Back to Top
fixer1958 View Drop Down
Orange Level
Orange Level
Avatar

Joined: 13 Feb 2010
Location: kansas
Points: 2434
Post Options Post Options   Thanks (0) Thanks(0)   Quote fixer1958 Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 6:45am
Chaska you have a pic of that 16hp weedeater?
Back to Top
iowallis View Drop Down
Silver Level
Silver Level


Joined: 04 Jun 2017
Location: North Iowa
Points: 371
Post Options Post Options   Thanks (0) Thanks(0)   Quote iowallis Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 6:55am
Originally posted by Hubert (Ga)engine7 Hubert (Ga)engine7 wrote:

Dave, down here pi R round, not square.

My algebra teacher would ask me to find the "X". I would say "How would I know where the X is, you were the one married to her".
Back to Top
DanD View Drop Down
Orange Level
Orange Level


Joined: 11 Sep 2009
Location: WI
Points: 856
Post Options Post Options   Thanks (0) Thanks(0)   Quote DanD Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 7:43am
Just as the earlier post said it's simply a ratio of diameters here. Can forget about pi since it just drops out of the equation. Here is the simplified equation. 1750/3600×5.5=2.67. So a 2.75" diameter pulley (if you can find that size) would run it ever so slightly faster.
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 87869
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 8:11am
and since the motor is 5 HP instead of 3 HP, maybe add 10% so the 2.75 inch becomes 3 inch pulley.
Like them all, but love the "B"s.
Back to Top
desertjoe View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 23 Sep 2013
Location: New mexico
Points: 13696
Post Options Post Options   Thanks (0) Thanks(0)   Quote desertjoe Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 8:43am

  Well,,,so many THANK YOU'S to all of ya'll Gurus for all the help,,,,,Clap Hey Chask,,I took some screen shots of the link you posted,,that will come in handy,,,if I can talk that dude outa the motor(s)ClapClap
Back to Top
farmboy520 View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 22 Jun 2016
Location: Beason, IL
Points: 553
Post Options Post Options   Thanks (0) Thanks(0)   Quote farmboy520 Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 9:25am
You might check your contacts in your pressure switch. Sometimes the arc of when they start the motor fries them and your not getting the correct voltage to your motor and you think it's going south.
On the farm: Agco Allis 9695, 7060, 7010, R66, Farmall H, and Farmall F20 (Great Grandpa's)
Back to Top
TimNearFortWorth View Drop Down
Orange Level
Orange Level
Avatar

Joined: 12 Dec 2009
Points: 2014
Post Options Post Options   Thanks (0) Thanks(0)   Quote TimNearFortWorth Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 11:09am
When I sold high end rotary screw compressors (Kaeser), we would promote a little 3 or 5hp stand-alone for small shops that had a recip. They could use their existing air receiver and keep the old reciprocating unit as a back-up. Had a distributor I set up that I also used for air piping on big jobs, guy was good in black iron or copper of all sizes and I learned plenty from him as he also fixed plenty of folks worn out recip units.
As I-R quality had gone downhill with India made units, Saylor Beall was a standout replacement "pump", tougher than pretty much all the newer units sold by the old name brands. Hanging intercoolers made them last as they dissipated heat well, then the Chinese copies hit the market.
The "Fushang" copy of the SB is tough and very inexpensive for anyone wanting a good reliable recip replacement pump.
Common shaft sizes, look up the sheave od requirement for different motors and go.
Would not run any recip without a low level oil switch as cheap insurance.
Back to Top
jaybmiller View Drop Down
Orange Level Access
Orange Level Access


Joined: 12 Sep 2009
Location: Greensville,Ont
Points: 24694
Post Options Post Options   Thanks (0) Thanks(0)   Quote jaybmiller Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 12:01pm
All compressor 'heads' have a range of RPMs. Slower ,they last longer. Faster they'll supply more CFM( pumping more air )
a 2.75" pulley will give same  as you have now, a 3" will be slightly faster, and belt may last longer.
3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water
Back to Top
chaskaduo View Drop Down
Orange Level
Orange Level
Avatar

Joined: 26 Nov 2016
Location: Twin Cities
Points: 5200
Post Options Post Options   Thanks (0) Thanks(0)   Quote chaskaduo Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 2:41pm

Bruce (Fixer1958) I just covered it up with tarping and all bungeed down for the winter yesterday.  This one is not mine but looks the same.

 
That's actually the gas tank cap sitting on the console, should be on the tank under the hood.


Edited by chaskaduo - 10 Nov 2019 at 2:43pm
1938 B, 79 Dynamark 11/36 6spd, 95 Weed-Eater 16hp, 2010 Bolens 14hp
Back to Top
TMiller/NC View Drop Down
Orange Level Access
Orange Level Access


Joined: 11 Sep 2009
Location: Lenoir, NC
Points: 1776
Post Options Post Options   Thanks (0) Thanks(0)   Quote TMiller/NC Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 4:10pm
Multiply drive (motor) pulley size by drive (motor) rpm divide by driven (compressor) pulley size equals driven (compressor) rpm... work back to find new motor pulley size..

         1750 X 5.5 = 9625 / 14 = 687.5 compressor rpm

          687.5 X 14= 9625 / 3600 = 2.6736 new pulley size
Back to Top
fixer1958 View Drop Down
Orange Level
Orange Level
Avatar

Joined: 13 Feb 2010
Location: kansas
Points: 2434
Post Options Post Options   Thanks (0) Thanks(0)   Quote fixer1958 Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 2019 at 5:29pm
Didn't know Weedeater tagged a riding lawnmower.
I was waiting to see a 16hp weed wacker.
Back to Top
desertjoe View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 23 Sep 2013
Location: New mexico
Points: 13696
Post Options Post Options   Thanks (0) Thanks(0)   Quote desertjoe Quote  Post ReplyReply Direct Link To This Post Posted: 11 Nov 2019 at 2:36am

 Hey FarmBoy...great idea,,!! it sure might be the pressure switch as it does not do the slow down all the time,,and when it does,,it will usually speed back up to normal RPM after runnin at the slow down rate,,,,Gonna try filing the contacts today,,,,
 Hey Tim,,it good to hear from you,,Guy,,!! I agree with the rotary screw compressors,,I just don't like the higher speeds they run at to make the air,,,,,WinkLike ole Jay says run em slow and they live longer,,,,
 Say Chask,,,that has to be the very first Weed Eater brand rider I ever seen,,and I've worked on a whole bunch of them,,, Good lookin machine,,!! Just you wait til ole Shameless sees them yellow wheels,,,he gonna think that is one of them Green tractors he like so much,,,,,ClapLOLLOL
  thas great info, TMiller,,THANKS. Clap
 


Edited by desertjoe - 11 Nov 2019 at 2:39am
Back to Top
chaskaduo View Drop Down
Orange Level
Orange Level
Avatar

Joined: 26 Nov 2016
Location: Twin Cities
Points: 5200
Post Options Post Options   Thanks (0) Thanks(0)   Quote chaskaduo Quote  Post ReplyReply Direct Link To This Post Posted: 11 Nov 2019 at 7:02am
Joe, I'm sure Shammers will understand it's for them citybot weeds of mine. It shows all kinds of respect to my Allis B, so does my 79 Dynamark, 91 Dakota, and 96 Caravan. Allis is 81 yrs old now.
Hey Fixer, I wish I could sling a 16hp hand held weed wacker around, talk about needin some cannons.
1938 B, 79 Dynamark 11/36 6spd, 95 Weed-Eater 16hp, 2010 Bolens 14hp
Back to Top
Stan IL&TN View Drop Down
Orange Level
Orange Level
Avatar

Joined: 13 Sep 2009
Location: Elvis Land
Points: 6730
Post Options Post Options   Thanks (0) Thanks(0)   Quote Stan IL&TN Quote  Post ReplyReply Direct Link To This Post Posted: 11 Nov 2019 at 8:29am
Joe try to keep the RPMs close to what it was. The compressor will heat up more the faster you run them and if too fast it will cook itself and you will be looking for a new one. Just saying.
1957 WD45 dad's first AC

1968 one-seventy

1956 F40 Ferguson
Back to Top
DaveKamp View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 12 Apr 2010
Location: LeClaire, Ia
Points: 6069
Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveKamp Quote  Post ReplyReply Direct Link To This Post Posted: 17 Nov 2019 at 12:27pm
Originally posted by DMiller DMiller wrote:

I can agree Hubert, PiE R Round, but Pi R Squared too!! I LOVE Pie, square pie, round pie, triangle pie, any kind of Pie!!


I'll drink to that!!!

Okay, so here's some notes to add:

MANY compressors don't run well when going TOO SLOW... it's because they're frequently splash-lubricated.  Some compressors (like the rotary screws Tim was talkin' about) use 'differential pressure' (high-vs-low side) to siphon oil from the reservoir up into the workings and bearings... so one needs to know EXACTLY how they work, before arbitrarily changing speed.

Some compressors (like the big Quincy that I'm rebuilding right now) have the option of running in different modes, and as a result, they have different lubrication methods, if you choose to run in a different mode, the lubrication system must be changed accordingly, but typically, compressors of that caliber are very well documented.

running a compressor slower WILL reduce noice, and heat (Boyle's Law).  Joe's single-stage pump was designed to push a large volume, but it takes special consideration to run high pressure.  My Brunner V4 is a two-stage unit, and while it was designed for a 10hp 3hp motor, I run it on a 2hp capacitor start... and it does fine, but I've made sure everyhing is 'right' for the circumstance.  The unloader mechanism's setup can be critical to starting ability with a small motor.  The unloader's function is to relieve head pressure from the pump on shutdown (keeps from blowing out seals in the pump, and blowing compressor oil all over the shop), and allow for a no-pressure load on startup.  It does this with a check valve at the tank, and a known volume between tank and pump, and a valve that 'dumps' pressure in this volume at shutdown.

In the case of my Brunner, the unloader activates on motor shutdown, it vents the volume between pump and tank check valve.   There's other methods of unloading, and there's different unloading 'modes', particularly on high-quality systems, so know your pump's methods before going willy-nilly.

When you go to a smaller pully, there's less contact surface of the drive belt, which means reduced belt capacity.  This being the case, people who do a motor swap from 4 pole (1800rpm) to 2 pole (3600rpm) motor frequently experience belt slip, and they counteract that by increasing belt tension, which puts substantially more load on the compressor's shaft bearings, and on the motor.  There's a variety of ways to combat this... going to matched dual-belts, or a speed reduction jackshaft... and of course going to a toothed-belt drive.

It will probably be fine with a lower-power motor at 3600 with a smaller sheave, but hopefully these notes will help you understand what you're facing if it doesn't work properly at first try.
Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
Back to Top
LeonR2013 View Drop Down
Orange Level
Orange Level
Avatar

Joined: 01 Jan 2013
Location: Fulton, Mo
Points: 3500
Post Options Post Options   Thanks (0) Thanks(0)   Quote LeonR2013 Quote  Post ReplyReply Direct Link To This Post Posted: 17 Nov 2019 at 3:47pm
Hey Joe, want to figure it the easy way? All you have to do is multiply the size of your small pulley times your motor RPM, and divide the outside diameter of the big wheel into it. Working maintenance in a sawmill years ago I had to build several gear reduction systems, even double reduction using this method and they worked fine.    Leon

Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.10
Copyright ©2001-2017 Web Wiz Ltd.

This page was generated in 0.059 seconds.


Help Support the
Unofficial Allis Forum