Replies

1. 
   JerryPacMan | Oct 22, 2004 05:00pm | #1

   The link below is very good to learn everything you need to know about motors.

   http://www.baldor.com/pdf/manuals/PR2525.pdf

    

    

   Life is what happens to you when you're making other plans .

2. 
   RickL | Oct 22, 2004 05:43pm | #2

   Jeff, you aren't still agonizing over whether to swtich the  motor or go with a phase converter  on that jointer? I'm curious as the nature of your motor question. As a woodworker you don't need to know a lot about motors. A local motor repair shop can guide you on why to choose what motor for what ever reason application is best. Jerry's link and some visits to motor websites should be all you need. The motor books are more technical and get into engineering. A book called Practical Electric Wiring  by Richter and Schwan has a section on motors and controls. It has all you need to know about motors from a woodworkers viewpoint and it's easy to understand.

1. 
   Jeff | Oct 23, 2004 01:17am | #3

   Rick

   No, but thank you for remembering.

   I bought a nice 3Hp GE motor for the jointer with the same shaft size to reuse the pulleys and everything.

   Believe it or not, I've been so busy this summer that I haven't had any shop time at all.

   I haven't touched the jointer or anything else in the shop for almost 3 months!!!!

   This question has to do with a fan for a Finish room I built with the shop addition (built last year, but haven't had a chance to use while I've been so busy)

   I installed a free 24 inch Tube-axial fan in the wall of the finish room last spring before I got so busy.

   No motor with it, so I figured I would put a 1Hp 1375 (+/-) rpm motor on it as recommended by Grainger for the fan.

   Then got into figuring the CFM and wondering what the speed should really be.

   Then got confused about this, because someone said the size of the motor determined the CFM.

   But, shouldn't rotation speed (RPM) and pulley size determine the CFM on the fan and not the HP?

   SO, before I buy a motor I thought it was time to do some reading.

   The room is 8ft, by 10 ft deep, 8 ft high.  Fan is installed in the wall at 5 ft high.

   Filters and make-up air are all set. fan is ready to go, just needs a motor.

   Any thoughts on this would be helpfull.

   Jeff

    

   PS: I'll finally get into the shop again in a few weeks.

          Projects are starting to pile up.

          Only a few more outdoor projects to finish up,  mostly windows.

1. 
   RickL | Oct 23, 2004 01:57am | #4

   Call Grainger technical for the answer.

1. 
   Jeff | Oct 23, 2004 02:43am | #5

   Rick

   I never thought of that.

   Thanks.

   Jeff

    

1. 
   RickL | Oct 23, 2004 03:02am | #6

   Focus on your woodworking and use the technical experts of various companies to help with other tasks. I believe Grainger has an 800 number. Haven't called them for awhile but they have different specialists available for their products.

2. 
   Jeff | Oct 23, 2004 04:09pm | #7

   Rick

   I'll give Grainger a call this week.

   Hopefully, they'll have the answer right off, as this can't be too odd a question.

   My biggest problem is that I was brought up by my parents to solve my own problems.

   They felt that I should be able to find an answer to everything on my own.

   So now, years later, I still need to research as much as I can and learn as much as possible on any topic I get interested in.

   You can't believe the size of my library and information I've accumulated over the years.

   Jeff

   PS:  You can't believe the number of companies  I've talked to over the years who actually know less about their products then I do, or experts on topics who can't answer (right or wrong) some basic question I've asked, and I obviously know more then they do. 

   Sorry, don't mean to be tooting my horn or anything, just stating my feelings.

   Jeff

   Edited 10/23/2004 9:18 am ET by Jeff in Vermont

3. 
   RickL | Oct 25, 2004 11:07pm | #11

   Jeff, the key is to find the right guy in the company who knows the product. You just didn't talk to the right guy. There will always be someone at the company who will know more about his product than you do. 

   I've been surfing the web for 10 years in the beginning I think  I asked 5 questions about things. Well no one was able to give a good answer and I learned how to do searches to find the answer myself so I never have to wait around. Basically there are no new questions, just new people asking the old questions.

   I was doing machine repair professionally long  before the web and OWWM. There's no official school to learn  it but I know where to get the answers and have a long list of technical specialists at my disposal and can still find info without the web like the old days

4. 
   Jeff | Oct 26, 2004 01:38am | #13

   Rick

   I've had so much good luck with the people here (such as yourself) getting help as needed that spending the time surfing and searching the web becomes almost unnecessary.

   Mostly faster to ask for help as needed.

   I'm not the most computer savy, and my computer is slowwwww....

   And don't think I don't appreciate the help.

   Thank you

   Jeff

5. 
   Crunk | Oct 25, 2004 08:47pm | #9

   Focus on your woodworking and use the technical experts of various companies to help with other tasks. I believe Grainger has an 800 number. Haven't called them for awhile but they have different specialists available for their products.

   AMEN TO THAT.  If I'd spent that little time in my shop the last thing I would be worried about would be the fan for the finishing room.  I'd suggest that the poster stick a box fan in the hole and build something.

6. 
   Jeff | Oct 26, 2004 01:33am | #12

   Boss

   Please don't get me wrong.

   That's what I did when I needed to ventilate the room, was to stick a box fan in the hole on a bracket.

   I haven't avoided the shop, just had too many projects outside the shop this summer to spend any time in the shop.

   Literally worked 7 days a week since June.

   Now I'm caught up as of the end of next week, so shop time becomes available to work on things till spring.

   Just thought I'd try to finish up the finishing room as one thing I kind of need shortly.

   Most of the winter will be in the shop.

   Jeff

2. 
   BarryR | Oct 25, 2004 07:25pm | #8

   Rick, the fan's rotational speed and basic design do determine the CFM.  But moving air (like anything else) requires effort, and the HP of the motor must be sufficient to do that work.  If the rotational speed of the fan is fixed, and the HP required to do the work are known, you can choose just about any sized pulleys and motor speed you need to get the required fan shaft RPM.  Obviously, you need to choose motor RPM and pulley sizes that make sense - a 1 RPM motor probably would result in some strange and unworkable pulley sizes, as would a 10,000 RPM motor.  In theory though, either could be used.

3. 
   JohnWW | Oct 25, 2004 09:45pm | #10

   Jeff,

   Grainger or the fan's manufacturer will have the information you need. 

   If you are going to be spraying with flammable solvents, the fan and motor both need to be specialized "hazardous location" types to prevent ignition and a fire or possibly an explosion, filters won't prevent fumes from reaching the fan.  Hazardous location fans can be found in the Grainger's catalog, costing around $600.00 for a 24 inch model. 

   John W.

4. 
   WayneL5 | Oct 26, 2004 02:24am | #14

   CFM for a given fan is determined by the fan speed.  Since you have the fan and know the CFM you want, you use the fan curve (provided by the manufacturer) to determine what speed to spin the fan to get that CFM.

   Next, you look at that same chart to determine how many horsepower it takes to spin the fan that fast.  Then you select the closest standard size motor with that much or larger hp.  For example, if it takes 1.2 hp you'd buy a 1½ hp motor, the closest standard size at or larger than your need.

   Motors come in standard speeds, usually about 50 rpm or so less than 1200, 1800, or 3600 rpm.  (There's a technical reason why these are the speeds AC motors run at.)  Then, you select a combination of pulley sizes that spins the fan at the needed rpm using a motor running at one of the standard speeds.

   If you were doing a rigorous design, you would also use selection tables to get the right belt size to carry the horsepower you need, but you'll be fine if you get a belt that matches the fan pulley.

   Grainger should be able to send you the fan curve.

1. 
   Jeff | Oct 26, 2004 02:18pm | #15

   Wayne

   Yeah, I've already figured out I need to call Grainger for info.

   I didn't know about the fan curve.

   My original problem started with needing to know how many CFM I needed and spiraled into a more complex question on motors.

   I'm on hold till next week now.

   Family emergency and I'm headed to Florida to see my dad tomarrow nite.

   Will get back to everybody next week.

   Thank you

   JHeff