I've had an annoying and reoccurring problem with my Edwards Ironworker (my FAVOURITE shop machine). It would shut down for no reason every once in a while. I know these machines are built for decades of use (even my model which is the smallest they make), so I started with the assumption that it was electrical.
I knew my 220V single phase electrical connections were correct—even though I never had it checked by a pro when I wired it years ago. But I understand this stuff reasonably well. When I once got the telltale smell of insulation and Bakelite I knew where to look. What I noticed was that either the terminal block connection was always coming loose, or there would be heat damage on the insulation close to the (screw) terminal connection.
I'd go inside and retighten the screw terminals that led to the line cord to no avail. It was just puzzling me what was going on because I'd never had such a persistent vibration problem. The stranded 12 gauge I'd used as my line cord kept coming loose, likely due to the vibration of the hydraulic pump. I tried everything: over-torquing the set screw in the terminal block (still came loose); Loctite 290 kept the set screw locked as advertised (wires underneath came loose); solder-tinning the wires (still came loose); and finally a flat heat shrink crimp lug (failed immediately). Then it hit me. The stranded wire—whether tinned or not—was the problem. Tinned copper wire is soft and collapses with vibration unless it has a structure around it. Untinned copper fans out under the set screw and causes heat damage because only half the conductors are functional. A terminal block that allows a "Y" yoke or "Hook" lug would solve the problem too; but some terminal blocks (like mine) only allow the wire itself to be inserted. These are the issue.
The solution proved to be a wire ferrule. If you've never used these before they are great. Sure they make everything look neat and tidy, but they have functional value too. They ensure all the strands in your wire are conductive—which means you've not trying to run 20 amps through only 6 of the 12 strands, for example. They provide a square (or hexagonal) tinned copper surface for the screw terminal to contact tightly, and one that doesn't deform like stranded wire does. But my favourite feature is the tiny serrations on the ferrule left over from the crimping dies. I'm not sure if these are intentional, but they sure help grip the terminal screws—preventing them from coming loose. I guess another feature of ferrules is the insulated jacket that provides some measure of strain relief while ensuring any stray wire strands don't cause a short circuit.
I've only used really tiny ferrules (20-28 gauge) in hobby electronics before, so this was the first time I used them with 12 gauge. I used to think they were gimmicky because they just made everything look so nice. But now I really appreciate their purpose. It's been 6+ months now, and when I was in the shop a few minutes ago I thought, "my ironworker hasn't failed for a long time." So I opened up the electrical box and inspected the connections with the ferrules. They were still tight as ever and there was no evidence of shorting.
WRT crimpers—I'm a huge fan of Knipex tools from Germany. But their version of a front loading ferrule crimper is almost $300 and tough to justify. Even their side loader is $230. Side (lateral) loaders can be found on Amazon for $25 to $35 and work just as well. You only need a front loader for confined cabinet use I think. I used to buy ferrules from places like B&E in Calgary. They sell kits of maybe 6 sizes with 20/size for $35. But now you can find a 1200 piece kit on Amazon for $17, and bundled with a crimper for less than $40. Gotta love that.
Hexagonal crimpers crimp a shape closer to a circle which is good for a lot of smaller terminal blocks. But I've only ever used a square crimper, which works fine in all my applications from hobby electronics to industrial metal working machines now.
Here's a good beginner vid on ferrules:
I knew my 220V single phase electrical connections were correct—even though I never had it checked by a pro when I wired it years ago. But I understand this stuff reasonably well. When I once got the telltale smell of insulation and Bakelite I knew where to look. What I noticed was that either the terminal block connection was always coming loose, or there would be heat damage on the insulation close to the (screw) terminal connection.
I'd go inside and retighten the screw terminals that led to the line cord to no avail. It was just puzzling me what was going on because I'd never had such a persistent vibration problem. The stranded 12 gauge I'd used as my line cord kept coming loose, likely due to the vibration of the hydraulic pump. I tried everything: over-torquing the set screw in the terminal block (still came loose); Loctite 290 kept the set screw locked as advertised (wires underneath came loose); solder-tinning the wires (still came loose); and finally a flat heat shrink crimp lug (failed immediately). Then it hit me. The stranded wire—whether tinned or not—was the problem. Tinned copper wire is soft and collapses with vibration unless it has a structure around it. Untinned copper fans out under the set screw and causes heat damage because only half the conductors are functional. A terminal block that allows a "Y" yoke or "Hook" lug would solve the problem too; but some terminal blocks (like mine) only allow the wire itself to be inserted. These are the issue.
The solution proved to be a wire ferrule. If you've never used these before they are great. Sure they make everything look neat and tidy, but they have functional value too. They ensure all the strands in your wire are conductive—which means you've not trying to run 20 amps through only 6 of the 12 strands, for example. They provide a square (or hexagonal) tinned copper surface for the screw terminal to contact tightly, and one that doesn't deform like stranded wire does. But my favourite feature is the tiny serrations on the ferrule left over from the crimping dies. I'm not sure if these are intentional, but they sure help grip the terminal screws—preventing them from coming loose. I guess another feature of ferrules is the insulated jacket that provides some measure of strain relief while ensuring any stray wire strands don't cause a short circuit.
I've only used really tiny ferrules (20-28 gauge) in hobby electronics before, so this was the first time I used them with 12 gauge. I used to think they were gimmicky because they just made everything look so nice. But now I really appreciate their purpose. It's been 6+ months now, and when I was in the shop a few minutes ago I thought, "my ironworker hasn't failed for a long time." So I opened up the electrical box and inspected the connections with the ferrules. They were still tight as ever and there was no evidence of shorting.
WRT crimpers—I'm a huge fan of Knipex tools from Germany. But their version of a front loading ferrule crimper is almost $300 and tough to justify. Even their side loader is $230. Side (lateral) loaders can be found on Amazon for $25 to $35 and work just as well. You only need a front loader for confined cabinet use I think. I used to buy ferrules from places like B&E in Calgary. They sell kits of maybe 6 sizes with 20/size for $35. But now you can find a 1200 piece kit on Amazon for $17, and bundled with a crimper for less than $40. Gotta love that.
Hexagonal crimpers crimp a shape closer to a circle which is good for a lot of smaller terminal blocks. But I've only ever used a square crimper, which works fine in all my applications from hobby electronics to industrial metal working machines now.
Here's a good beginner vid on ferrules:
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