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Recent content by jfriddell

  1. jfriddell

    pressure and volume changes for a liquid filled system

    Engineers: I'm working on a subsea project where I intended to de-mate a control line coupler pair. I know when I de-mate the coupler pair under pressure a very small volume of fluid (liquid) will be released from the system. The couplers have a poppet which will seat upon demate and thus...
  2. jfriddell

    Pole Barn??

    Check with the Midwest Planning Service: www.mwps.org Look under their Construction Section. Try the Post-Frame Building Handbook publication: http://www.mwps.org/index.cfm?fuseaction=c_Products.viewProduct&catID=710&productID=6452&skunumber=NRAES%2D1&crow=15
  3. jfriddell

    potential energy of a compressed gas

    Members: It seems then there is no tried and true method, theoretical or empirical, for estimating stored energy due to gas compression in a pressure containing piece of equipment. Is this what I am hearing from the group? I'm dealing with volumes in the 20,000 in3 to 2 in3 range depending on...
  4. jfriddell

    Pressure dew point question

    Soundside: Your problem sounds like a psychrometrics problem. Anytime you are dealing with air and water, psychrometrics typically apply. If you know the incoming air RH, then with a psychrometric chart, you should be able to predict any other state, such as dew point temperature, enthalphy...
  5. jfriddell

    potential energy of a compressed gas

    All: I have been asked to assist with reworking the projectile calculations guideline for my company. We perform a significant number of high pressure hydrostatic and gas tests of pressure containing equipment. I would like to request assistance from compression experts to assist me in...
  6. jfriddell

    Can simple transformers be used in both "step-up" and "step-down&

    Professionals: I do not have a transformer yet. I wanted to research before proceeding with the project. In all likely hood, the supply will be the 120 VAC generator as described and the load will be a 240 VAC motor circuit. Since my load is not large, only 400 W, I wanted to see if I could...
  7. jfriddell

    Can simple transformers be used in both "step-up" and "step-down&

    Electrical Professionals: As I read the posts, I see there is some discussion about my actual voltage needs. My 240 VAC load is a three wire system of two small motors. My 120 VAC supply is a simple, off the shelf gasoline powered generator made by Honda, Colemand, DeWalt, etc. with standard...
  8. jfriddell

    Can simple transformers be used in both "step-up" and "step-down&

    I am strictly dealing with 1-phase electricity. I have an application where I have a 120 VAC only output generator (2000 W) and I wish to run a very small load (~ 400 W) which requires 240 VAC. Can a 240 VAC primary/120 VAC secondary transformer be used to "step-up" 120 VAC to 240 VAC? If...
  9. jfriddell

    PE Exam

    I took the TX Ag Engr. PE exam in October 2004. I was lucky in that I had some older classmates and business associates who had taken the exam in the last 2-3 years. Their material and study guides were fairly current. As TerraSouth said, dig out all of your old text books. The Midwest Plan...
  10. jfriddell

    large volume pump station, variable demand

    Pumpdesigner, et. al.: I get the impression that you are leaning toward a multi-stage turbine with a diffuser in each bowl. From your discussion, it sounds as though that set-up would accomodate my needs as best as possible. All I would have to worry about is controlling the discharge...
  11. jfriddell

    large volume pump station, variable demand

    Gang: My turbine supplier has only suggested that a constant pressure valve, such as a Cycle Stop valve (CSV), may be a less expensive alternative and would provide similar pump throttling capabilities without the extremely high initial cost of the VFD for such a large motor. Do you all see...
  12. jfriddell

    large volume pump station, variable demand

    Valued Respondents: Thank you for the advice so far. As this is strictly an irrigation water supply, there is little need for sophisticated controls. The greatest level of sophistication that I've considered thus far is a manually controlled VFD, but my turbine pump supplier has leaned me...
  13. jfriddell

    large volume pump station, variable demand

    Forum Participants: I'm working on a project where the customer has one large diversion point for his water right from a river. Water will be drawn from the river through a large wet well (like a reservoir can pump) structure using a vertical turbine pump. Decreed flowrate is 4,500 gpm. This...
  14. jfriddell

    determining voltage drop for 1-phase lines

    Gang: Thanks for all the great answers. I feel more confident in my ability to ensure that I'm recommending the proper wire size. Have a great weekend. Jeremiah
  15. jfriddell

    determining voltage drop for 1-phase lines

    Gang: I'm a "lurker" on this board and have found many helpful tips and knowledge. Thanks to all who make these boards so interesting and helpful. Now for my question: I'm an agricultural engineer who is quite rusty on my elementary electricity. Could somebody refresh me on the proper...

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