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  1. #31
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by cba_melbourne View Post
    If one uses the same connectors and the same pinout for all machines and all VFD's one owns, the items become functionally interchangeable. Good in an emergency, or to troubleshoot.
    Thanks for posting the links to those 3P plugs and sockets. The P&S approach Is what I am after for testing 3P motors with my HP rig.


    I am a little confused about the ratings on the plug itself.


    I guess they refer to two different standards?
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  2. #32
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    Quote Originally Posted by Pete F View Post
    Ray have you used this vfd? Single phase output inverters are not common from what I've seen, and this could be quite significant. I'm also often asked about single phase VFDs for other applications like pool pumps etc.

    The article describing it can't be viewed on my ipad, so I'm curious as to what types of single phase motors it can be used on.

    To the OP, while I'm a strong advocate for inverter drives, I think a vfd would be overkill in this application, especially if cost is a serious concern. I'd suggest a combination of pulleys would probably be sufficient to vary the speed in the ranges you'd need.

    With regard using plugs and sockets, be aware that having unnecessary plugs and sockets is considered poor practice in the electrical world.
    Hi Pete,

    No, I never got around to buying one, the cheap Huanyang's eliminated the interest.. I did study the design pretty carefully when it first came out, and it has some nice features. The design is made possible by using an off the shelf IGBT bridge module. one thing I was dissapointed in was that the source code for the software wasn't released with the project, the author will sell you the hex file, and I think pre-programmed dspic32's

    Other than that, it looks like an excellent design, I think it will run most single ac induction motors, maybe not those with centrifugal switches? But I think you can do the same with any V/F drive...

    Ray

  3. #33
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    Ok thanks Ray, I'll definitely keep that in mind for future. I try to keep my kit building days well behind me (takes up too much time and reminds me of work, albeit in a past life) but the price was reasonable and if there was an application I definitely needed it for it could be just the ticket. Ironically now I have a "solution" available I'm struggling to find a problem that couldn't be resolved another way!

  4. #34
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    Quote Originally Posted by RayG View Post
    Hi Pete,

    I think it will run most single ac induction motors, maybe not those with centrifugal switches? But I think you can do the same with any V/F drive...

    Ray
    They state that it definitely won't run motors with centrifugal switches.
    Rob.

  5. #35
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    Ok sorry, I had to post and shut down the ipad as it was starting to misbehave. I'm about ready to send this thing flying out my hotel window ... If only the window will open. I'll add a new post rather than editing, lest I upset the Edit Nazi.

    I may well have misunderstood your last sentence Ray, but my understanding is that at least some (not sure if it's a generalisation however) manufacturers VFDs won't run single phase motors as they detect the missing phases as a motor fault and just won't allow it to run. Similarly with single phase input, in theory it's perfectly possible with a derate, but I know for a fact that SEWs won't do it as I've spoken with their engineers about that and the drive thinks its a fault and won't run. Quite apart from motor controlling, a big part of an inverter's role in industry is to protect motors too, and I think that's something we tend to overlook as it's probably lower down our priority list compared to picking up a bargain on ebay

  6. #36
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    Quote Originally Posted by BobL View Post
    Thanks for posting the links to those 3P plugs and sockets. The P&S approach Is what I am after for testing 3P motors with my HP rig.


    I am a little confused about the ratings on the plug itself.


    I guess they refer to two different standards?
    Yes, different testing standards can have different voltage and current ratings. The application may affect what standards must be met. For example, if used in an industrial environment in Germany or Switzerland the VDE or S+ rating of 400V and 16A will apply. But if this connector is to be used in a device which needs to be sold worldwide, it will be limited to lower UL or CSA ratings, in this case 250V 12A. Even worse, if for example installed in a medical device and sold worldwide it will be limited to UL ratings, and the device as a whole will certainly have to be tested too....... and possibly re-tested in some individual countries....
    Also note you can order these sockets and connectors with screw terminals, crimp terminals or solder terminals, and this choice will affect the current rating too.

  7. #37
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    Quote Originally Posted by Pete F View Post
    ..........With regard using plugs and sockets, be aware that having unnecessary plugs and sockets is considered poor practice in the electrical world..........
    If the OP wants to use one VFD for several machines, plugs and sockets are a necessity. Poor practice would however be to use plugs and sockets that are unsuitable for the task.

  8. #38
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    This is a single phase input / single phase output VFD:

    http://www.invertekdrives.com/variab...-single-phase/

    You can download the user/installation manual for more information. Do not expect it to work as smoothly as a 3 phase output VFD, especially not at lower speeds. It is best suited to variable torque loads such as pumps and fans. With pumps and fans, the load increases proportional to the square of the motor rpm. In other words, at half the rpm the VFD needs only to supply one quarter of the power. Whereas 3-phase output VFD's are constant torque up to base speed and constant power above it, which makes them much better suited to drive machine tools.

    Because the demand for single phase output VFD's is small, there are only very few makers, and prices are high. That is why iIt is usually cheaper to buy a new 3-phase motor, rather than to convert an existing single phase motor to variable speed with a 1ph output VFD.

  9. #39
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    Quote Originally Posted by BobL View Post
    Thanks for posting the links to those 3P plugs and sockets. The P&S approach Is what I am after for testing 3P motors with my HP rig.


    I am a little confused about the ratings on the plug itself.


    I guess they refer to two different standards?
    Just as a matter of information...and caution.

    There are a great many plugs with all sorts of voltage and current ratings...and those ratings may well be valid.

    The common 3 pin XLR audio plug has pretty high voltage and current ratings...but it is entirely unsuitable for mains supplies.

    BUT

    In Australia all plugs and sockets for connection to mains supplies or used with mains supplied equipment are "prescribed items" and must be manufacturerd, tested and approved under australian standards and electrical regulations.

    There are very good reasons for this...they include durability, suitability and compatability.......in particular the way the plug connects and in what order the pins of the plug engage.

    Please DO NOT use non approved and non type correct plugs on your electrical equipment.

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  10. #40
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    Quote Originally Posted by soundman View Post
    ..........................

    In Australia all plugs and sockets for connection to mains supplies or used with mains supplied equipment are "prescribed items" and must be manufacturerd, tested and approved under australian standards and electrical regulations.

    There are very good reasons for this...they include durability, suitability and compatability.......in particular the way the plug connects and in what order the pins of the plug engage.

    Please DO NOT use non approved and non type correct plugs on your electrical equipment...................

    cheers
    I fundamentally have to agree. But it is not always a simple "black and white" consideartion. Some common sense has to be applied too.

    Can we really expect the buyer of say a 3/4HP VFD, to use an Australian plug and socket like this one to hook up the motor?
    32A.JPG
    - The smallest these come are 3x20A. Enough to run a 10KW motor. This type of plug/socket is actually larger than the 0.55kW VFD itself. Just does not make sense to me.
    - And the VFD itself gets hooked up to mains with a small 10A single phase IEC plug, same as used for say a kitchen blender?
    - Also consider that such a VFD from China only costs new about $150. The above socket and connector costs alone anywhere between $75 and over $200 for an Australian brand name.
    - It will be difficult to safely wire a 1.5mm cable into the monster 20A pins of that plug, so you got to use a stiff oversized cable too.


    Or assume someone wants to integrate his 1 or 2HP VFD inside his machine tool cabinet. There is still a valid argument to use connectors, in order to keep disassembling and maintenance of the machine easy. Here too you would want to use plugs and sockets of an appropriate size for the task.
    After all, we can buy here in Australia machine tools with integrated variable speed control, and we do not see them use such oversized motor connectors either. I believe what matters more, is for us to make sure we choose a type and make of connector that is safe for the task, and conforms to mayor internatonal electrical safety standards. After all its for our own personal use in a one off project, not for sale to the public.

  11. #41
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    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Quote Originally Posted by Ueee View Post
    Now I have a 2hp 2 pole 3 phase motor here wired in delta.
    I lied.....its wired in double star. Still correct for 220v hookup though!

    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  12. #42
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    UM..yeh it is black and white....and very large penalties apply...particularly in QLD.

    If the VFD dose not have compliant terminals......either compliant terminals have to be fitted or the VFD has to be enclosed.

    After all the mention of plugs in this thread is to allow the use of a single VFD with multiple motors.

    This is a plain straight forward appliance connector issue.....it is clearly......black and white...discribed in AS300 and AS3100.

    Most of these VFD units are not intended to be stand alone devices....many do not even have a housing that makes them compliant unless they are mounted in a switchboard or equipment housing.

    please do not use VFDs with noncompliant plugs and sockets .....unless they are fit for purpose and then enclosed in a housing as described in the standards.


    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  13. #43
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    Quote Originally Posted by cba_melbourne View Post
    - It will be difficult to safely wire a 1.5mm cable into the monster 20A pins of that plug, so you got to use a stiff oversized cable too.
    I don't use 1.5mm cable for *anything*, the minimum I use is 2.5mm and you most certainly can get it in flexible - I have a 5 core (4 plus earth) rubber sheathed lead on my surface grinder, hooked up to a 415V 10A Federal on/off switch with a 415V 10A 5 pin plug for the wall socket. The cable is very flexible. So frankly you're wrong, you're not looking in the right catalogs. I thought those connectors you showed earlier were pretty neat but if they're not approved for use with mains current be it 240V or 415V, I'm not having them on *any* of my equipment. I don't care what voltage or amperage they have stamped on the side. OTOH they might be perfect for my 12V DC boat stuff - except the amperage rating sucks there. PDW

  14. #44
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    Quote Originally Posted by cba_melbourne View Post
    Or assume someone wants to integrate his 1 or 2HP VFD inside his machine tool cabinet. There is still a valid argument to use connectors, in order to keep disassembling and maintenance of the machine easy. Here too you would want to use plugs and sockets of an appropriate size for the task.
    After all, we can buy here in Australia machine tools with integrated variable speed control, and we do not see them use such oversized motor connectors either. I believe what matters more, is for us to make sure we choose a type and make of connector that is safe for the task, and conforms to mayor internatonal electrical safety standards. After all its for our own personal use in a one off project, not for sale to the public.
    It is not a valid argument, it is considered poor practice as noted above. It's why these things are hard wired.

    The argument that "it's just for our own use" is all very well, until it's not for our own use. We sell the equipment, we kick the bucket and (dad's crap) gets sold, we lend the tool to somebody else, somebody uses it without our knowledge, and so it goes on. There is no place for bodgy setups when it comes to mains power and higher voltages, and what may seem like an innocent short-cut, or good idea, at the time could have serious, even fatal, consequences to an innocent person futher down the track.

  15. #45
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    As it hasn't been inserted yet,
    Quote Originally Posted by DavidG View Post
    DISCLAIMER

    No liability is accepted by UBeaut or the Wood Working Forum's administrators
    or moderators for advice offered by members posting replies
    or asking questions regarding electrical work.
    We strongly advise contacting a Licensed Tradeperson for all electrical work.

    WARNING

    Information supplied within posts is not to be considered as detailed formal instructions to complete a task.
    Members following such information do so at their own risk
    But I agree with the Peters - using non approved electrical fittings can be risky.
    Pete's comment about it's "not just for our own use" is every true and why when setting up the VFD on my surface grinder I wanted to get the wheel speed right at 50Hz - if that machine ever leaves my TLC, I'd like to know the wheel won't be overspeed if someone decides to remove the VFD for what ever reason.

    Michael

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