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  1. #41
    Just had a play with the transformer, with 240Vac through the 380V terminals it gave secondary reading of 95V on each and 190V across both... could be usable?

    Thanks for the link to the caps, they look a bit more substantial!
    would something like this bit a better solution for the bridge rectifier https://www.mouser.co.uk/ProductDeta...n%2Fkm7zBfw%3D

    Thanks for the photos, very handy to be able to visualise the whole set up.

    I have no idea on the photos, all of mine were rotated through 90 degrees as well! I tried everything I could think of but they just revert back to side ways!

  2. #42
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 13 Hours Ago Has been a member for 2-3 years. Has a total post count of 136. Received thanks 24 times, giving thanks to others 4 times.
    That is a bit of a mother and IXYS is a "premium" brand. That first one you linked to from CPC would be absolutely fine. These diode bridges are generally very robust.

    A better solution would now be to connect the 2 primaries in series and the 2 secondaries in series (as they are already).

    I take it that the 380V windings are the brown and blue. Each contains 2 wires - one from each limb. You could separate them and connect them in series so that there is a (floating) centre tap formed by one brown and one blue. Then the voltage on each primary would be 120V and the voltage across the ends of the series connected secondaries would be your 95Vac. Then you would simply feed the 95Vac into a bridge rectumfrier and you would get your 130Vdc or so.

    Apart from reterminating the wires, you are almost done. It's a rather large beast but there is no extra expense and alongside your 2 tonnes of cast iron, it's all relative!

  3. #43
    ok I'll stick with that first one I found, save a few quid as well!

    I manage to un cover some terminal labelling hiding under the grime! pictures attached of which wires do what..

    Yes, as you say, the 380 windings are terminals 1.3 (Brown) and 1.1 (Blue). So leave the secondary as is, and separate the pairs of blue and brown and have a single blue, blue and brown together, single brown..? Hopefully I'm not being dumb and that's what you mean!

    At this stage I think the money saving out weighs keeping the size and weight down, at least for now. So I'll persevere with this lump seeing as its quite close to where I need it to be. your not wrong though, it must weight somewhere between 50-60kg easily.
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  4. #44
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 13 Hours Ago Has been a member for 2-3 years. Has a total post count of 136. Received thanks 24 times, giving thanks to others 4 times.
    .Yes, single blue, blue and brown together, single brown would work.

    You can always swap the transformer out later when things are running and you are feeling flush. Keep your beer tokens for other stuff.

    My original transformer is even bigger, as it's a 3-phase jobby. Which reminds me, I must get it down the scrappie when it reopens....

  5. #45
    Awesome, I'll get them swapped over today.

    Yeah I probably will end up changing it long term to be honest, its not the nicest thing to look at beside the machine..

    Yeah I would! probably fetch a fair amount in scrap for something that size!



    Have you got any recommendations for relays, I've attached a wiring diagram for the controller I've bought which calls for a 24Vdc relay to switch the power for the drivers ( I think!).

    Would a solid state work alright for this? or go for a non-latching type?
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  6. #46
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 13 Hours Ago Has been a member for 2-3 years. Has a total post count of 136. Received thanks 24 times, giving thanks to others 4 times.
    You could use an SSR but TBH, they can be a bit expensive. If you decide to go that route, make sure you buy a DC one, not an AC one. If you try to switch a DC load with an AC SSR, it will go on but you won't be able to turn it off. CPC have a very limited range but Farnell and RS have a lot more to choose from.

    That schematic shows all of the axis drives passing through the relay. That would make it a BIG relay and switching DC is more tricky for the contacts than switching AC. If you go this route, you'll be needing a big clonker of a relay, possibly more of a contactor and make sure it's actually rated for the DC current and voltage you would switching in a fault condition. I haven't gone that route myself. I use the drive enable signal into the drivers to inhibit them if I need to use the e-stop or the controller / VFD get upset. If the worst comes to the worst, I could always kill the mains using the front panel isolator. Certainly, if you switch the high power DC loads, you probably won't want to be using an SSR unless your bank account is very healthy.

    I have SSRs for the flood and air (300VAC type) and for the spindle gear solenoids (60VDC). My mains is switched with a front panel isolator and I have a time delay relay after that to soft start the 100VAC transformer / diode bridge / electrolytic circuit. The e-stop kills the drives and the Acorn and the VFD via the low voltage inhibit circuit. As I said, if that were to fail I'd kill the mains. This isn't an industrial safety critical system, just like the other systems here, so there's no point kidding yourself that there is one approach you must take.

    If you go the route I went, there's no need for heavy relays in the power circuit. If not there are probably contactors out there that are in common usage for this kind of application that somebody here could recommend.

  7. #47
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 2 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,457. Received thanks 281 times, giving thanks to others 7 times.
    I wouldn't personally use an SSR for anything deemed critical, as a common SSR failure mode is to fail short circuit.
    A suitably sized relay, or contactor is a more robust option.

    That diagram you posted, it would appear the AXBB uses an output to power up the drives. Personally, I'd use that output as an enable signal to the drives, and have power controlled via a suitable e-stop system.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  8. #48
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 13 Hours Ago Has been a member for 2-3 years. Has a total post count of 136. Received thanks 24 times, giving thanks to others 4 times.
    I'd agree it's better to run the enable signal to the drives rather than switch the DC. I don't see any role for an SSR here either, other than coolant etc.

    As you say, it's simpler to run an AC side contactor on an e-stop circuit if you can be bothered, rather than switch the lower voltage DC side. Personally, I'd rather not throw everything out each time I hit the e-stop but that's a matter of preference.

  9. #49
    Great info, cheers!

    So it certainly sounds like a better option to tweak that layout somewhat, guess I need to have a think of what I want out of the set up. worryingly I hadn't even thought about an E-stop system yet!! I would at a minimum hope to have an e stop to kill the motors and spindle, whilst keeping the system powered still.

    We had a machine at work that had floor mounted E-stops and god knows why but they literally killed everything, PC included, so you lost all your datums and tool offsets. Most annoying when you accidentally kicked them!! I don't want that...

  10. #50
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 13 Hours Ago Has been a member for 2-3 years. Has a total post count of 136. Received thanks 24 times, giving thanks to others 4 times.
    Personally I wouldn't want that. On my machines, the e-stop stops the spindle turning and the table moving. The most likely cause would be senior moment / finger trouble causing the tool to dive into something unauthorised, or the tool clogging up and breaking, or realising the speeds and feeds are somewhat ambitious. Mistakes have been made!

    If you have a crash, there's no need to kill the whole machine. And if the whole thing really goes native, the isolation switch will stop any arguments. Unless you are planning to sell your equipment commercially, it's your call what you do. There's no right or wrong answer although as there are humans involved, I'm sure there are strong opinions in favour of all manner of different solutions.

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