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  1. #121
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Anorak Bob View Post
    In some cases three wires will be secured in a single terminal. Previously I would have twisted the wires together with pliers and clamped them in the terminal en masse.
    That's what I would do.

    If they still didn't fit I would look at connecting pairs further back in the circuit or group them all into a single fat insulated connector and then run a wire from the connector to the contractor. Ugly as, but it would work.

    For tidiness I would use StudToys suggestion of a terminal block with loops.

    I do have to ask "why such massive wires?" The motors are small ones and I'm sure you could get away with wires that are 2/3rds or even half those shown.

    Have you given up on the momentary touch switches starting the VFD directly?
    Remember the VFD will act as the no-volt switch.

  2. #122
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    Quote Originally Posted by PDW View Post
    My electronics techs had the best gear money could buy - it was your tax dollars after all - and generally, if it was an important joint, it was soldered then had 2 layers of heat-shrink over the top. Using tinned wire as standard.

    But that was a marine environment.

    My purely ignorant approach is, if it's high voltage (240-415V) and inside a house/shed, I crimp. If it's low voltage, I solder. If it's likely to be exposed to salt air, I use tinned wire, solder and heat shrink. Replacing cables running through bulkheads, inside deck heads etc is not something you want to do.... in my boat I've got dedicated cable ways under the deck head just so running cable is simple(r) and future work easier.

    YMMV.....

    PDW
    Yes, marine environment is a bit special, we did an instrumentation job once for Tenix, on the Anzac class frigates, your tax dollars at work! They just love their glue-line heatshrink and anti-capillary wire.. almost as much as they like sikaflex.

    Are you using that anti-capillary stuff on your boat?

    Ray

  3. #123
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    Quote Originally Posted by Anorak Bob View Post
    My plan is to use a couple of magnetic contactors to enable the remote switching of the VFDs via the grinder's control panel's momentary on and off switches. Below are a few photos of the type of contactor I'll use. They are obviously second hand. I don't know whether the quality of the existing connections is industry standard.

    Should my wires be tinned before securing them in the terminals?

    In some cases three wires will be secured in a single terminal. Previously I would have twisted the wires together with pliers and clamped them in the terminal en masse. There is insufficient room to accommodate 3 forked crimped on connectors, even two are tight. A soldered clump would also present a problem.

    Bob.
    Hi BT,
    You can get bootlace ferrules sized for dual cable entry. ( but you'll need a crimping tool.. ) Try and route the wiring to avoid having three together... Just make sure when you're done the terminals are all done up tight. If you can go over the terminals when you've finished and get another 1/4 turn, then they ain't tight enough.. One check you should always do on switchboards is run at full load for a while and then go around each terminal with an infra red thermometer looking for hot spots. You'd be surprised how quickly a loose terminal get's hot.

    Ray

    Edit: Are you sure you need the contactor?

  4. #124
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    Quote Originally Posted by RayG View Post
    Yes, marine environment is a bit special, we did an instrumentation job once for Tenix, on the Anzac class frigates, your tax dollars at work! They just love their glue-line heatshrink and anti-capillary wire.. almost as much as they like sikaflex.

    Are you using that anti-capillary stuff on your boat?

    Ray
    Anything on a weather deck will be tinned marine grade wire. Inside the hull, I'll use a mix depending on intended use. Heat shrink is the way to go wherever possible with cables run inside ducting and junctions inside IP56 junction boxes. If the moist sale air can't get to the exposed ends, they can't corrode. At least that's the theory - occasionally works. Then there's the dickheads with pressure washing/blasting equipment that blast right through insulation on expensive cabling to a 3D GPS system and you don't find a problem until intermittent faults manifest themselves after 2 weeks at sea with another 8 weeks to go before returning to port.

    We used to joke that our ships were held together with Sikaflex, velcro and cable ties....

    PDW

  5. #125
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    Just so there's no confusion Dean, a properly crimped joint doesn't need to be soldered if it has been crimped correctly. However there's no downside to soldering AFTER crimping and considerable benefits in doing so, particularly in some environments. The reason I posted about it here is that it obviates the requirement to ensure a good mechanical crimp for the connection to be both mechanically and electrically sound. I've been seeing an increasing number of posts that have poo-pooed conventional soldering and advocated other methods of terminating based on theoretical nonsense. Presumably under the mantra that people can be baffled with BS if you quote enough Google sources. Two of the recent gems that have come up recently have been heat and mechanical strength of soldered joints. From a practical perspective both are complete BS in almost every situation where soft soldering is conventionally used. To prove it, solder two ends of wire together in a conventional lap join and then try to pull them apart. While relying on a soldered join for mechanical strength is bad practice, a soldered joint is nevertheless quite strong so good luck with it! In the case of temperature, unless the environment is high temperature, assuming conventional wire etc, if you get in to a situation where the solder joint is melting, you've got bigger problems to deal with!

    Bob, the "correct" way to terminate the wires is to crimp connections on them (your choice as to whether then to solder!). As mentioned by Stuart, it is recommended not to tin a wire and then mechanically fasten with a screw. It is due to the cold flowing of the solder. Having said that, again the difference between theory and practice is that I'd also always tin the wire. One reason is to prevent oxidisation of the bare copper should the termination subsequently be removed and re-attached. However the other reason is that, once again, I've lost count of the number of times I've seen stray strands of wire make a dash for it and caused shorts elsewhere. On the other hand I've never seen a properly tightened connection then "cold flow" to cause issues. If you do decide to terminate bare copper wire, and obvious tip, but one that I often see ignored, is to lay the wire such that tightening the screw pulls the wire in to the connection and not the other way around. Sorry if that's too obvious.

    Edit: Peter I once had an intermittent problem on a flux-gate compass* nobody could find the solution to. It turned somebody had nicked the wire with a drill and the damaged area was right where it went through a bulkhead, hence it couldn't be seen even after extensive visual inspections. All was fine until Mr Wire met Mr Sea Water.

    *Just dashing out the door and remember that job now,it wasn't a fluxgate, rather a sonic transducer to a doppler log. A brilliant piece of technology BTW, measures boat speed by measuring the doppler shift of the water between two transducers. Super accurate and no moving parts (ie an impeller that constantly fouls). I'll need to look up if that's still done these days as that was over 20 years ago now.

    Pete

  6. #126
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    Is this the moment where I admit that my crimping pliers came from a fishing tackle shop?

    Michael

  7. #127
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by RayG View Post
    Hi BT,
    You can get bootlace ferrules sized for dual cable entry. ( but you'll need a crimping tool.. )
    BT, if you want to do that - I have the crimper


    Try and route the wiring to avoid having three together... Just make sure when you're done the terminals are all done up tight. If you can go over the terminals when you've finished and get another 1/4 turn, then they ain't tight enough.. One check you should always do on switchboards is run at full load for a while and then go around each terminal with an infra red thermometer looking for hot spots. You'd be surprised how quickly a loose terminal get's hot.
    Good idea. Now I have a good excuse to borrow the IR camera from work. I love playing around with that thing.

  8. #128
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    Quote Originally Posted by Michael G View Post
    Is this the moment where I admit that my crimping pliers came from a fishing tackle shop?

    Michael


    Of course that's only acceptable if you also purchased your soldering iron and multimeter from Crazy Clint's discount house...

    Ray

  9. #129
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    Quote Originally Posted by Michael G View Post
    Is this the moment where I admit that my crimping pliers came from a fishing tackle shop?

    Michael
    Can't see the problem - I use side cutters a lot. If it needs to be better I get one of my electronics friends to do it for me (ie hooking up the 25HP air compressor motor again).

    Aside from the mechanical strain issues, a lot of problems come from using wire that's at its limit for the amperage it carries - see Ray's comments WRT temperature rise. I generally look at the recommended size for the amperage then go up one size. OK it costs a little more, so what, it means that I'm always well inside the current carrying limit and a poor connection, if it has sufficient contact area, is likely also not going to overheat.

    I agree with Ray about tightness of screwed joints too, surprising how many times I've opened up a sub-board in my workshop and found I can nip up the screws a little, when I *know* they were tight the last time I checked them....

    PDW

  10. #130
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    Pete F

    Just so there's no confusion Dean, a properly crimped joint doesn't need to be soldered if it has been crimped correctly. However there's no downside to soldering AFTER crimping and considerable benefits in doing so, particularly in some environments. The reason I posted about it here is that it obviates the requirement to ensure a good mechanical crimp for the connection to be both mechanically and electrically sound. I've been seeing an increasing number of posts that have poo-pooed conventional soldering and advocated other methods of terminating based on theoretical nonsense. Presumably under the mantra that people can be baffled with BS if you quote enough Google sources. Two of the recent gems that have come up recently have been heat and mechanical strength of soldered joints. From a practical perspective both are complete BS in almost every situation where soft soldering is conventionally used. To prove it, solder two ends of wire together in a conventional lap join and then try to pull them apart. While relying on a soldered join for mechanical strength is bad practice, a soldered joint is nevertheless quite strong so good luck with it! In the case of temperature, unless the environment is high temperature, assuming conventional wire etc, if you get in to a situation where the solder joint is melting, you've got bigger problems to deal with!
    No confusion. I agree with you completely. I just need to decide which crimpers to get and order them.

    Re "Cold Flow" More of that bs that could occur in certain circumstances?

    PDW

    I agree with Ray about tightness of screwed joints too, surprising how many times I've opened up a sub-board in my workshop and found I can nip up the screws a little, when I *know* they were tight the last time I checked them....
    Last weekend I played around with, and got my lathe going on a temp basis. I tried to disconnect some of the extraneous wiring inside the electrical box. Chuck guard switch and extra E stop. When I tried to undo the screws holding these wires, the slot in the screws gave way with the result that I could not undo them. These are in Din Rail connectors. Just joining one wire to another. They are not very old. The extra bits were installed within the last 6 years or so. I remember when it happened, as the lathe was at work then. I think the sparky did not want to have to retighten them. I just cut the wires.

    Dean

  11. #131
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    Quote Originally Posted by Stustoys View Post
    Hi BT,


    No.......don't tin under a mechanical joint.*
    If you really want to get excited just run the wire to a terminal block and loop to the other wires.

    Are you sure you need the contactors anyway? Have a look in Joe's/Simons threads about using momentary switches directly to the VSD.

    http://www.woodworkforums.com/showthread.php?t=183843

    Stuart

    * should add... if I was using fine multi strand wire I just might anyway............just coz it can make life easier......
    Stu,

    I had a look at Joe's thread. The VFD I'm using to drive the work head motor is a General Electric VAT 20, basically a rebadged TECO FM 50. I have perused the GE manual but I can't find anything covering the use of momentary switches when the remote or external terminal function is selected.

    The 13's TECO FM50 is run via the remote terminal but the switch is latched.

    BT

  12. #132
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    Quote Originally Posted by RayG View Post


    Of course that's only acceptable if you also purchased your soldering iron and multimeter from Crazy Clint's discount house...

    Ray
    Of course not! That would be silly.
    The soldering iron was given to me. The box had something about "perfect for soldering on the roof" - why you would want to join wires while up there I don't know. The multimeter came in a box of miscellanea from St Vincent de Pauls. Occasionally the needle needs a tap but it seems to work.

    Michael

  13. #133
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Michael G View Post
    Of course not! That would be silly.
    The soldering iron was given to me. The box had something about "perfect for soldering on the roof" - why you would want to join wires while up there I don't know. The multimeter came in a box of miscellanea from St Vincent de Pauls. Occasionally the needle needs a tap but it seems to work.

    Michael
    My 40 year old analog MM fell into a 30 L electrolysis tank. It was just sitting on the edge of the bench and the next minute it was taking a bath. I pulled it out and tipped out the liquid, pulled out the battery, rinsed it under the tap and then in distilled water, then blew it out with the compressor and let it dry in the sun. It still work. Like yours the needle needs the odd tap past 1/2FS.

    The Dental surgical instruments I use for taking motor surgery cam from the dump.

    My favourite phillips screwdriver came from a box on a scrap metal pile. It was in a steel drum along with a bunch of other tools that were all stuck to the bottom of the drum with varnish. The 2L empty varnish can was still in there. My guess is the tools were in the steel drum and a can of varnish was either dumped or fell into the drum and the lot was chucked onto a scrap metal pile. I pulled them out and most of the varnish just peeled off and the rest came of POP using a wire wheel on a grinder.

  14. #134
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    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    I don't know if you can get them still but i have seem and used crimp connectors that just have a straight round end specifically for using in contactor clamps etc. Not even sure what they are called...

    FWIW I crimped and soldered the fittings on the terminal box ends of the star point wires in Andre's motor. Crimped with needle nose pliers of course.....

    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.

  15. #135
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Ueee View Post
    I don't know if you can get them still but i have seem and used crimp connectors that just have a straight round end specifically for using in contactor clamps etc. Not even sure what they are called...
    Shoestring connectors.

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