Page 6 of 7 FirstFirst 1234567 LastLast
Results 76 to 90 of 93
  1. #76
    Join Date
    Jun 2010
    Location
    Canberra
    Posts
    1,322

    Default

    I'm going to join the haters - that is an offensively good deal.

    I'm going to guess that the caps are snubbers for the pressure switches' contacts.

    If you want some help with hydraulic symbols, if you sign up here: https://www.hydraulics.training/symbols they'll email you a link to a very handy PDF.

    Speaking of symbols, the adjustable relief valve on the pump seems to have a solenoid valve after it - is that to disable the relief valve on command?

  2. #77
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Steve,

    PDF Data sheet, for the device in the first picture !

    3124016_Data Sheet_en.pdf

    I've nothing on the Pressure control valve.
    Best Regards:
    Baron J.

  3. #78
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default Workshop press build - hydraulic questions

    Quote Originally Posted by BaronJ View Post
    Hi Steve,

    PDF Data sheet, for the device in the first picture !

    3124016_Data Sheet_en.pdf

    I've nothing on the Pressure control valve.
    Thanks John. I found that much more useful that you might have thought.

    I thought it was part of the solenoid and had no idea it was just an indicator. I've just been out and pulled off a couple of the plugs and can see how it fits together. When the solenoid is energised then the indicator LED will be on!

    And Tony was correct earlier, the solenoids are actually 110v (as per the hand drawn schematic).




    There must be something missing from this whole setup as from what I can see there's:
    a. No 110v supply for those solenoids
    b. Nothing to actually control them - unless its set up as a system where the pressure switches produce a continuous cycling action of the outputs to the rams.

    Here’s a photo of the control valve details.




    Steve

  4. #79
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    Quote Originally Posted by RustyArc View Post
    I'm going to join the haters - that is an offensively good deal.

    I'm going to guess that the caps are snubbers for the pressure switches' contacts.

    If you want some help with hydraulic symbols, if you sign up here: https://www.hydraulics.training/symbols they'll email you a link to a very handy PDF.

    Speaking of symbols, the adjustable relief valve on the pump seems to have a solenoid valve after it - is that to disable the relief valve on command?
    Thanks Rusty. I'll check it out as I can use all the help I can get with the symbols

    No idea what that solenoid valve does!!

    Steve

  5. #80
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    New cylinder is in excellent condition apart from the bit of chrome worn off on the rod.

    Nice piston, with wear ring and what looks like some sort of bypass valve so you can’t drive it hard against the gland.
    The piston just screws onto the rod.




    Seals are nice and tight and I couldn’t physically pull it out of the cylinder by hand while held horizontally in the vice. Resorted to using a bit of compressed air for assistance.

    The bore is in perfect condition so I’m thinking I’ll just make a new rod and throw it back together with the same piston seals and new gland seals.

    Steve

  6. #81
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
    Posts
    362

    Default

    Quote Originally Posted by OxxAndBert View Post
    Resorted to using a bit of compressed air for assistance.
    I know I am being a bit of a tosser here but please, please never use air to remove pistons from cylinder.
    I launched a 300 mm piston weighing about 40kg about 3m into the air one day. Left a large dint in the concrete when it landed.

    I walked into a pneumatic repair shop on day to see a rod and piston hanging though the sheet metal wall. It was left there as a reminder to others as to what can happen when using compressed air to remove things.
    Its something those in the industry know not to do, but still do it.

    These days I sacrifice the oil (or water) and push bits out.

    Something I meant to mention before, if you are pulling things apart to keep track of where things go, take pics, take notes and use coloured cable ties.

    DSC08403.jpgDSC08426.jpg

    Tony

  7. #82
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
    Posts
    362

    Default

    After all that I forgot to ask, how bad is the chrome on the rod. Being on the non-load side and a low cyclic rate it does not have to be perfect. As long as its smooth.
    The finger nail test is a good one. If it does not catch your finger nail as its dragged across it you should be OK. Sanding with emery paper down to about 1000 can give good results.

    Tony

  8. #83
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    Thanks Tony - you're definitely not being a tosser and its very valid to be warning about the dangers of compressed air.

    I agree its not the right thing to do, and so I don't look like a completely clueless goose I'd better explain that I was using a small diameter duster gun in the 1/2" fitting, wrapped with rag (definitely not fully sealed) and the rod/piston were supported/restrained by a lifting sling connected to my small gantry. I had my wife standing beside it to balance it as it came out and used just enough pressure to get it to move. I'd already had it moving by hand so knew it wasn't stuck hard.

    In hindsight a more appropriate way of doing it where it was would have been to hook the rod eye up to the gantry and pull it out.

    Good tip on the coloured cable ties.
    I definitely take lots of photos (IMO mobile phones are the best thing that ever happened to disassembly!).

    Edit: The chrome isn't bad, and if I didn't already have some suitable rod here and wasn't wanting to modify the free end I would just run it as-is.

    Steve

  9. #84
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default Workshop press build - hydraulic questions

    Getting back to the power pack...
    Today I hooked up a VFD to it so I could get a soft start on the motor as I was concerned about what might happen if it started instantly going backwards!
    Had some issues with the existing cable that was connected inside the main wiring panel. When I first tried to start the motor the VFD errored out instantly with an overcurrent code.
    Double checked the parameters I'd set but they were all good.
    Thinking I'd bought a lemon with a cooked motor I dragged out the megger and did some quick tests. With the star links removed from the terminal box on the motor I was seeing a short between the windings. Traced it back to the input wiring connection inside the main box - somehow shorting between phases. The motor itself was fine.

    Hooked the motor up directly to the VFD and it started fine, and in the correct direction. There was flow as I could see the filter differential gauge move slightly when the motor was running. But zero pressure on any gauges.

    Looking at the hydraulic circuit diagram, I think I need to switch valve #14, as its currently just porting the pump output to the tank. Does that look correct?

    hydraulic diagram.jpg

    If so, what are my options?
    The solenoids are currently 110v50hz. Having a separate 110v power supply is going to be a bit painful.
    I'm planning to use a 240v VFD to power the motor, so will have access to 240v for solenoids if need be.
    Is it just a case of getting a 240v solenoid and fitting it? If so are they pretty standardised, or will I need to get one to match this particular make and model of valve?

    Alternatively, since I really have no need to turn the supply on and off is there an easy way I can just permanently leave it in the "on" position?
    I'm thinking along the lines of replacing the solenoid valve with a fixed port plate, or somehow mechanically holding the existing valve on.

    Pretty sure this is the valve concerned. The one at the top with the single solenoid on the RH end. Ignore the black indicator units that are sitting on top in the second photo






    Steve

  10. #85
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
    Posts
    362

    Default

    When the pump is started 14 lets the oil go straight to tank (no head pressure on pump). When either valve 12 is operated valve 14 shuts in one direction forcing oil to 12 then opens another port and diverts the return oil coming from 12 (and or pressure relief 10) and sends it to tank.

    The solenoids are standard type. You can buy them in all sorts of voltages. (have a chair ready when you get the price).

    14 can be removed and the lines hard plumbed but it will mean the pump is always pumping at pressure. Not really a problem if used for short periods but if on for a long time oil temp will rise so a cooler is needed.

    Tony

  11. #86
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
    Posts
    362

    Default

    I have just seen your other post showing you have fitted a manual valve.
    This should be open centred, so dump all the electrical stuff. Go from point 9 on the schematic to the manual valve and then return 19 to go through the filter to tank.

    Tony

  12. #87
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    Thanks Tony.
    I was having a look online last night, and you are right about the price of those solenoids
    Generally one solenoid is more than I paid for the whole pack!!

    Given that all the valves etc are on the one big block and don't appear to be easily tapped into I think that the cost for fittings and plumbing to just bypass them is going to creep up pretty quickly by the time I plumb to both pressure and return.
    I've got a 110v output transformer here that I occasionally use for testing, so will have a play and see if I can just turn on valves 14 and 12 and get the output to the existing ports. I've already got hoses and fittings to connect to those.

    I was thinking the different voltage for the valves was going to be a hassle, but it might actually be the easiest way to do. I happened to find a 200w 240-110 stepdown transformer on ebay last night for under $20 delivered so have grabbed that in case I need it. Its packaged in a unit with fuses etc so will be a nicer testing platform anyway that my exposed multi-tapped toroid

    Steve

  13. #88
    Join Date
    Jun 2010
    Location
    Canberra
    Posts
    1,322

    Default

    Yeah, I was going to say that adding a 110V supply wouldn't be a big deal, particularly since it can be small as there's bugger-all current involved.

  14. #89
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    Yes. I checked the power usage on the solenoids and as you say it’s not much. 20W each.

    Steve

  15. #90
    Join Date
    Jun 2010
    Location
    Canberra
    Posts
    1,322

    Default

    Quote Originally Posted by OxxAndBert View Post
    20W each
    That's a bit more than I imagined. Left energised, they're going to build up quite a bit of heat, but in this application I guess they're not going to be left on terribly long. And they're attached to chunks of aluminium which would act as heatsinking.

Page 6 of 7 FirstFirst 1234567 LastLast

Similar Threads

  1. Hercus hacksaw hydraulic lifter - oil and other questions
    By StrayAlien in forum METALWORK GENERAL
    Replies: 33
    Last Post: 18th Nov 2022, 08:10 PM
  2. 40T Hydraulic Press
    By scottyd in forum METALWORK PROJECTS
    Replies: 19
    Last Post: 24th May 2022, 10:49 PM
  3. Need to build a workshop, share your experience
    By caskwarrior in forum METALWORK GENERAL
    Replies: 36
    Last Post: 28th Jul 2019, 11:51 PM
  4. Excavator hydraulic thumb build
    By asheddie in forum METALWORK PROJECTS
    Replies: 6
    Last Post: 3rd Nov 2016, 04:23 PM
  5. Hydraulic Press Jigs
    By Oldneweng in forum METALWORK GENERAL
    Replies: 4
    Last Post: 1st Jul 2012, 09:25 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •