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Recent content by tfry200

  1. tfry200

    Basic advice to control a Delta VFD-B for automated run-in cycle

    I follow you that I can control the VFD and get the electrical information using the Delta software. I will talk to delta about it but I was hoping that I could either control 4 units or at least run 4 instances of the program to control each. So are you guys recommending I set it up so the...
  2. tfry200

    Basic advice to control a Delta VFD-B for automated run-in cycle

    fangas, My company repairs these motors and it is our procedure to go through a run-in process to break in the bearings and ensure that everything is functioning as intended. They run without a load. We measure the temperatures at each bearing, and at the winding. I need to make a record of the...
  3. tfry200

    Basic advice to control a Delta VFD-B for automated run-in cycle

    jraef, You are correct on both points--the Delta VFD does have a RS485, and it can use MODBUS ASCII or MODBUS RTU, according to the manual. I've got a budget of 'minimal' :) Just kidding (well, kind of. ) I can probably spend a few thousand to do this. For the temperature recording I've been...
  4. tfry200

    Basic advice to control a Delta VFD-B for automated run-in cycle

    Hello everyone, First off, my disclaimer- I'm a mechanical guy. A bit of a computer geek on the side, but nothing crazy. What I'm being asked to do is to set up an automated run-in program for electric motors. We control these motors with four Delta VFD-B drives. What I want to do is step up...
  5. tfry200

    Need help with force calculation involving a ball bearing

    Desertfox, Are you talking about friction between the left wedge and the ball or the left wedge and the grounded vertical plane? for the wedge/ball I think I have them all in there? For the wedge/wall combination I see that I do not. (Also, it's not labeled for the wedge/wall on the right, but...
  6. tfry200

    Need help with force calculation involving a ball bearing

    Okay, Many many thanks for all the responses and assistance. Here's what I ended up with from summing the forces with and without friction. My numbers came out close to Zekeman's, and they also are similar to the graphical method mentioned. My results are attached. Think I've got everything...
  7. tfry200

    Need help with force calculation involving a ball bearing

    Okay I follow you with the forces on the ball. The way the ball sits into that curved support on the bottom is the only part of the system i'm not completely sure about, but I think ideally the actual position is more like this (see new attachment). The reason I think the force is 600/cos(75)...
  8. tfry200

    Need help with force calculation involving a ball bearing

    Hmmm...this is a pretty small system (the ball is 5mm dia) compared to the forces involved, so I've been ignoring the weight of the elements. Also, would it be possible to treat this as a frictionless problem?
  9. tfry200

    Need help with force calculation involving a ball bearing

    Hi all, I'm trying to solve the attached problem in order to understand the system so I can design a related tool. I have to admit I'm a little frustrated because I know at one time I could have solved this no problem, but I guess I've been away from it for too long! I'm trying to follow the...
  10. tfry200

    Controlling an industrial servo with a pc?

    Let me start off by saying I don't normally deal with servos or motion control or anything like that. But I'm being asked to! We need to test an AC servo motor we have in house. I'm told that there are motion control cards that can be purchased for a PC that can control a servo, and I've been...
  11. tfry200

    Heat transfer Q--equilibrium temperature of shrink fit onto shaft

    Hmm... only about 7 watts with h=2. Hardly seems significant, does it? I do see some stuff in my book about transient response...maybe I should look there? At that point I guess I would be kind of just going through it for the exercise, but it might not be a bad one to do. I'll let you know if...
  12. tfry200

    Heat transfer Q--equilibrium temperature of shrink fit onto shaft

    desertfox, Thanks for the input. I tried to nail down a little more accuracy using your formula as: Qr_alum+Qr_steel=-Qshaft To account for the two materials in the rotor. I pulled the mass numbers (in kg) off CAD, and got: Mr_alum=.199 Mr_steel=.955 Mshaft=1.924 (the actual shaft we will...
  13. tfry200

    Heat transfer Q--equilibrium temperature of shrink fit onto shaft

    Hmm..well that is good information also, so thank you for that! But what I am really after is: 'what is the hottest temperature the chilled shaft will rise to once the heated rotor is dropped on?' i.e.--after the rotor is dropped on, the rotor will begin to cool and the shaft will begin to get...
  14. tfry200

    Heat transfer Q--equilibrium temperature of shrink fit onto shaft

    My apologies. In above posting, I meant that I was hoping I could get an approximation of the system by assuming the ROTOR was solid steel, not the shaft. The shaft already is solid steel.
  15. tfry200

    Heat transfer Q--equilibrium temperature of shrink fit onto shaft

    Desertfox, The seals on this shaft are internal and are installed by the manufacturer. We can't change that, so are bound to their temperature range. The drawing I posted was of the shaft that we used to test the mechanical fit. I know it would be imperfect, but was hoping I could let the...

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