heavy duty quick connects for testing?

[eeinpa]

Need ideas for a way to quickly connect fairly heavy motor leads (up to ~2 AWG) for test purposes...

I like those little terminal strips for small wires where each one has a little lever you lift up to remove contact pressure. Does anyone know of a vendor who makes these in jumbo sizes?

Maybe I should start a company!

 

[OperaHouse]

I'm thinking about those buss connectors that you tighten a screw with a hex wrench. Now if you just replace that hex screw with a small Clippard BIMBA air cylinder that you screw in, that would be quick. Air line would insulate one terminal to the next. Likely you would have to apply one terminal at a time as you wrestle that size wire.

 

[itsmoked]

Can you get some of those cam-over nuts they use for things like camper-shells? You spin them down until they're so tight then fold them over for the final tightening. Baring that just some big knobbed screws that allow you to jettison tools will speed things up a lot.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[JERRYROBINSON]

In electric motor repair shops, they use alligator clips like the Welders use for ground clamps.

The key is they bring the volts and amps up gradually. This would not work well for an accross the line start.

There are other twist lock welding clamps that would work.

 

[jraef]

Spring clamps, as you mentioned above for terminal blocks) are not suitable for any load that might require #2 wire. They only go to 33A as far as I know, that is #10 wire.

Do you need to quickly connect plain stranded wire? Wires with crimp lugs already on it? Cable to which you will have or could have permanent plugs and receptacles attached?

Motor test benches, where they will be attaching separate stripped stranded wires, usually use something like a Kearney split bolt connector that has been soldered or welded to a bus bar. That gives you a quick "cage clamp" type of connection that adjusts well to a larger range of wires without the kind of physical damage you would see with more permanent mechanical bolt-on lugs (i.e. Ilsco lugs). For #2 wire as the max size though, I wouldn't worry about that and just use an Ilsco lug, then tighten it with an allen wrench. If you need it insulated, look at a Taylor or Marathon power terminal.

Kearney split bolt

Ilsco lug

Marathon power block

 

[jraef]

Accidentally hit Post instead of Preview...

You really shouldn't substitute convenience for safety by trying to use a spring loaded connector. I know that what JerryRobinson said is true about the alligator clips, but any safety engineer would have a cow if they actually saw that. The manufacturers specifically warn against using them for that purpose. they are actually called "grounding clips" to avoid being sued when they overheat and lose tension under load, then fall off and start a fire. I'm not saying people don't abuse them that way, it's just not a good idea.

 

[eeinpa]

Thanks for the many replies...

We would generally be connecting stranded individual motor leads which do not have lugs on them. It would be nice if the connector were quick to attach, yet safe.

I am trying to avoid spring clips at all costs. Even heavy duty welding type clamps are just ugly. And at 230 or 460 dc or 480 AC, I really don't like the idea of the things coming loose!

The idea of the split bolt connector brazed to busbar is interesting and might work out. A dedicated wrench could be chained nearby to keep it handy. The Marathon style insulated terminal block is probably safer, and I could chain a T-handle allen wrench nearby. We could also install the finger guard covers, and drill small access holes for the allen wrench.

The idea of the air cylinders is pretty clever! Maybe we don't need it THAT convenient I think you would still need some sort of mechanical advantage to get adequate clamping force. At hundreds of amps, I think need it tight.

The idea of the "cam over" fasteners is worth investigating... if I could find a cam over that would fit into an Ilsco style lug or Marathon terminal block, or a custom made block, it could eliminate the need for a tool to make the connection.

 

[CJCPE]

There are many types of toggle clamps available. Look at:

http://www.toolfastclamps.com/toggle4.html

http://destacoclamp.com

 

[MikeHalloran]

I learned to arc weld with twist grip electrode holders. I think some styles could grip a #2 wire okay. No tools to lose, no springs to anneal.





Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

Ahh there you go. Use single wide Marathon blocks two for each cable. Braze a tee handle into one of the Allen screws of each one. Use two per cable. Back to back. Then install a short piece of cable between each set of blocks using the sides without the brazed tee handles. This allows all the tee handles to turn without finger pinch points or colliding with the 'other' side's tee handle.

This ditches the hazard of chains.

Then you can use the short cable area for clamp ons or shunts. If one side is always connected then you only need one single block per side as no interference will occur 'across block'.

You will have to watch out for wearing out the blocks after a hundred uses. Use lots of the correct grease.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

Just be careful that those T handles will be hot!

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

Dip them in that green goo. Easier on the hands too.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ScottyUK]

Or use one which is designed not to kill the user:

http://www.sf-electric.com/en/produits/ficheprod.cfm?lnc=1&lnf=292&lnsf=527&lnp=38661

----------------------------------

Sometimes I only open my mouth to swap feet...

 

[itsmoked]

Those look nice. Wonder how they take to 1,500F brazing?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[sdb830]

What about using a Pin and Sleeve connector? This is the service they are designed for and they sell non metalic units upto 100Amps. Woodhead is one of many companies that sell them.

http://www.woodhead.com/data/current3539/pin20and20sleeveNEW.pdf

 

[jraef]

I interpreted his need to be as a test fixture, not a permanent installation. Pin and Sleave are nice, but a pain in the rear to install and de-install (?) over and over for a test fixture.

 

[controlsdude]

I have used 3 phase 480 quick disconnect connectors before so that maintenance can quickly change out a damaged power feed. I believe Pheonix Contact and Harding makes these type of connectors you want to use. I know their are others but these are probably the best manufacturers of said devices.

 

[eeinpa]

Thanks for all the suggestions everybody. I should emphasize that the need is for connection to leads for TEST purposes. I do not want to install lugs or any connector onto the motor leads, because the customers want bare leads and we would just be throwing away money. For this reason the pin and sleeve are not appropriate.

I think the Marathon block with some appropriate safety measures regarding the allen drivers is the way to go. Inexpensive, flexible. Even if I simply got an insulated allen driver, spaced the blocks far apart, and used plastic chain to keep it handy. Risk to personnel would be minimal. I feel far better about a positive connection like that than any type of alligator clip, welding clamp, etc.

PS The "short cable area" between the Marathon blocks (for clamp on meters) is inspired!

 

[thinker]

Consider using MELTRIC connectors (range 30A-200A)

 

[itsmoked]

eeinpa;

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com