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  1. Thread: Braking resister

    by BobL
    Replies
    3
    Views
    106

    I just checked my 2 braking resistors that look...

    I just checked my 2 braking resistors that look like the on in BJs photo

    One is for a 1.5kW Motor/VFD, it has a nominal resistance of 100Ω, while the other one is for a 2.2kW motor/vfd and that is...
  2. Thread: Braking resister

    by BobL
    Replies
    3
    Views
    106

    Well, . . . . you can just use something like a...

    Well, . . . . you can just use something like a bank of of incandescent light globes or an electric heater element
    BUT
    Their resistance varies with temperature.
    For example, using the light...
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    Said cake tin turns out not to be quite large...

    Said cake tin turns out not to be quite large enough bit according to SWMBO her Mum's place (40km away) has a stash of square cake tins that are about to be thrown out.

    To test the effect of...
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    Funny you mention "tin boxes" I was just 5...

    Funny you mention "tin boxes" I was just 5 minutes ago eyeing one of SWMBO cake/biscuit tins :D
  5. Describing VFDs and their V connection...

    Describing VFDs and their V connection requirements is tricky and that site looks like it has made a bit of a dogs breakfast with it but there's nothing actually incorrect in what they said.
    They...
  6. Replies
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    Yes it is a bit of a dog's breakfast so it does...

    Yes it is a bit of a dog's breakfast so it does not surprise me there are probs.


    Yep, I am ware of this, same with the PS. However these should show up as problems even on the bench when not...
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    Set up the mains power supply to the VFD and...

    Set up the mains power supply to the VFD and Microcontroller (MC) so they are powered from the same outlet as the coffee machine
    Remember I want to turn on the VFD / MC and coffee machine from the...
  8. I have a small WW lathe that came stock with a SP...

    I have a small WW lathe that came stock with a SP 240V 1/2HP motor.
    I ran a 1HP 415V Y motor using a 240V VFD for about 3 years without any probs before I converted it to ∆.
    At 50Hz it had about...
  9. A 240V 3P Motor can run from a VFD in either ∆ or...

    A 240V 3P Motor can run from a VFD in either ∆ or Y mode, BUT it has to be set up for not just "∆ or Y but "240V ∆" or "240V Y".

    It just so happens that if a 440-415V Y is converted to ∆ becomes a...
  10. It's not possible to convert this motor, you'll...

    It's not possible to convert this motor, you'll have to replace the motor or get it rewound.

    Most of the conversions I have undertaken have been single to 3 phase so involve complete motor...
  11. Replies
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    I found another issue contributing to the noisy...

    I found another issue contributing to the noisy TC problem.

    So that I don't have to turn on 3 mains switches (coffee machine, VFD/Motor, Micro-controller[MC]) just to have a coffee, I wired the...
  12. Replies
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    Me too. And I've tried restarting the browser and...

    Me too. And I've tried restarting the browser and no difference this time.
  13. Replies
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    That is whatI have done. I've done the...

    That is whatI have done.



    I've done the same but I wouldn't necessarily call them "happy"
  14. Replies
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    I replace the VFD to motor cable with a shielded...

    I replace the VFD to motor cable with a shielded cable and It had about the same effect as the large ferrite ring on the output ie it helps but does by itself not solve the problem.
  15. Thread: Foggy lens

    by BobL
    Replies
    2
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    165

    Have u tried warming it up with a hot air gun?

    Have u tried warming it up with a hot air gun?
  16. Replies
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    One of the most useful things I picked up when...

    One of the most useful things I picked up when scavenging stuff from the hospital demolition site was a roll of 6 core shielded cable. I think the cores are 1mm which is more than enough for the 1/2A...
  17. Replies
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    This thread should probably be moved over there...

    This thread should probably be moved over there as well.
  18. Replies
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    Sorry, I misread your post. I thought you were...

    Sorry, I misread your post. I thought you were asking about noise.

    The VFD speed is set on the Arduino box using an external potentiometer.
    I'm adjusting the speed using a pair of pots [one for...
  19. Replies
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    Nope - but it soon will be.

    Nope - but it soon will be.
  20. Replies
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    Thanks I thought that too and have spent a lot of...

    Thanks I thought that too and have spent a lot of time looking at power supplies.
    If it was this then it shouldshould show up all the time but there was only a problem when the VFD was on and worse...
  21. Replies
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    OK - we have significant progress. Firstly I...

    OK - we have significant progress.

    Firstly I put a large ferrite ring on the VFD output phases to the motor.
    382139
    WHALLA!
    This immediately dropped the AC on the TC Opamp output from ~500mV to...
  22. Replies
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    I know it sounds ridiculous, but it really has...

    I know it sounds ridiculous, but it really has cost me very little in hard $ and providers hours of fun and many hours of frustration



    I have no idea,

    There's only a problem when the VFD is...
  23. Thread: Budget Welders

    by BobL
    Replies
    17
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    1,375

    The "HD" on theBunnings HD 15A Lead with the...

    The "HD" on theBunnings HD 15A Lead with the 1.5mm cores refers to the ruggedisation of the plug and insulation rather than electrical HD.
    I'm using a 10m long x 2.5mm cored extension lead on a...
  24. Replies
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    I agree, I doubt a conventional impeller or...

    I agree, I doubt a conventional impeller or paddle wheel sensor will be sensitive enough. The best tech for low flow is ultrasonics as used in medical devices but these are out of my price range....
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    Thanks. No flow sensing happening yet itís just...

    Thanks. No flow sensing happening yet itís just pump substitution at this stage. The strain gauge to sense fluid mass arrived but I managed to break off one of the fine wires and had a devil of a...
  26. Replies
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    We have coffee! Today I assembled everything...

    We have coffee!

    Today I assembled everything inside the cupboard under the coffee machine and connected the stuff inside the cupboard through the 50 mm hole in the bench top to the machine.
    There...
  27. Replies
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    Finally got my pressure sensors so I could finish...

    Finally got my pressure sensors so I could finish up this project.
    Lucky I bought two because in between calibration and the prototyping I buggered one - that will teach me for buying cheapies. ...
  28. Replies
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    BSPT 1/8" uses 28 TPI, NPT uses 27" 1/4" and 3/8...

    BSPT 1/8" uses 28 TPI, NPT uses 27"
    1/4" and 3/8 BSPT uses 19 TPI ,NPT uses 18
    Typically these will thread inside each other for a few turns and then they stop.
    I had one today - a 1/8" pressure...
  29. Replies
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    Given it's Ozito I 'd be wary about what it says...

    Given it's Ozito I 'd be wary about what it says on the label.
    Interestingly the Ozito compressor oil does have an MSDS which says it's Western Gulf compressor oil.
    The air tool oil does not have...
  30. Replies
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    Compressor oil and air tool oils are quite...

    Compressor oil and air tool oils are quite different.
    Compressor oils are designed to withstand heat, pressure and repeated use.
    I wouldn't use air tool oil on any machinery as it's too "thin"...
  31. Replies
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    All good here on WW and MWF's. One site this does...

    All good here on WW and MWF's. One site this does happen on occasionally is the ABC. To get around this I restart the browser.
  32. Replies
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    I'm interested in the callipers. Thanks

    I'm interested in the callipers.
    Thanks
  33. Replies
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    The angular momentum of a full size set of blades...

    The angular momentum of a full size set of blades blades is still going to bite unless the blades are made out of something like foam rubber and then are not really going to work very efficiently.
    ...
  34. Replies
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    Well I would not put it like that, lots of going...

    Well I would not put it like that, lots of going around in circles trying to remember stuff I should know but have most inconveniently forgot.
  35. Replies
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    Still waiting for the pressure sensor to turn up....

    Still waiting for the pressure sensor to turn up.

    In the meantime I started on the micro controller- a $10 Arduino Uno clone.
    Initially its just going to monitor a few machine parameters an I...
  36. Replies
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    Nice job Nev. 99% of the time the forces on a...

    Nice job Nev.

    99% of the time the forces on a vice are across or down but sometimes it is upwards
    To counteract that and to tighten the vice onto the post what about something like this?
    Weld a...
  37. Replies
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    I like sheds idea. If you can't or don't want to...

    I like sheds idea. If you can't or don't want to do that then I would not go bigger than 1HP.
  38. Replies
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    If you canslightly loosen the belts so they can...

    If you canslightly loosen the belts so they can slip if things go pear shaped then you could put up to a 1.5HP motor on it. To facilitate that you would need to use a 2HP VFD (they usually come in...
  39. Replies
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    Is it gear or belt drive.

    Is it gear or belt drive.
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    I agree that it's easy to get spoiled. I mainly...

    I agree that it's easy to get spoiled. I mainly do small stuff in my shed and don't expect much from my small mill so I don't push it. I had more in mind more the chance of seriously stuffing my mill...
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    I have really good wood dust extraction on my 12"...

    I have really good wood dust extraction on my 12" tablesaw, so no mess with Al, Have to watch out for small off/cuts as the extraction may suck it right off the table - usually I cut 99% of the way...
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    I don't know the Centec but my experience with...

    I don't know the Centec but my experience with the little Hercus Mill has been the opposite. It too had a 3P 4P 1/2HP motor and I was worried it would be too small when I fitted a VFD and I made...
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    I'd be using some diagonal cross bracing on that...

    I'd be using some diagonal cross bracing on that frame.
  44. Replies
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    Zirconia (Zircon oxide, ZrO) is present in nature...

    Zirconia (Zircon oxide, ZrO) is present in nature and is about as toxic as Aluminium Oxide (Al2O3) and neither of them are know to have any significant health effects. You are more likely to be...
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    You can get them at Element14 or RS and cost...

    You can get them at Element14 or RS and cost around $5-6.
    However, (as I found out on one of Anorak Bob's VFD which had the same problem) the chances of the problem just being the thermistors is...
  46. Replies
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    With a hydraulic damper I find I can use 10-14...

    With a hydraulic damper I find I can use 10-14 for almost everything.
    On thin tubing I sometimes add a piece of wood.
    I do have a small thin kerf abrasive cutting wheel table saw that I use...
  47. Replies
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    Now that I think about it I agree and only one of...

    Now that I think about it I agree and only one of the 3 places I go to regularly uses a cold saw.
    The biggest place has about a dozen bandsaws and they're often putting stacks of up to 16 pieces...
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    I dislike noise so I dislike cut-off saws. When...

    I dislike noise so I dislike cut-off saws. When they start the cut-off saw up at the mens shed I go outside or over the road for a coffee. Not to mention the sparks and grey-goo dust they generate. I...
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    I have both Al oxide and zirconia belts of the...

    I have both Al oxide and zirconia belts of the same size for my finishers (900mm x 50mm and 150mm x 2m). I usually use the Alox for timber, Al, and light burr and light rust removal on steel. Zr gets...
  50. Replies
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    I have a 3P Italian 50 x 1560 mm (ie non-standard...

    I have a 3P Italian 50 x 1560 mm (ie non-standard size) belt sander I got for nothing about 5 years ago.
    I checked if other sizes would fit but smallest belt length that it would take was about...
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