# Disconnect dissection?



## Mcswain (Dec 25, 2016)

In class we have a disconnect that is not getting continuity between the terminals when the knife switch is thrown up into the on position. 
I'm assuming the contacts inside the inner workings that rotate are burnt or not making contact? Has anyone ever disassembled one and if so does this hypothesis sound correct?


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## MechanicalDVR (Dec 29, 2007)

This should be pretty easy to diagnose visually.


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## Mcswain (Dec 25, 2016)

Actually no! It seems as if the connection inside where you cannot see is not making contact. The plan is to remove and disassemble tomorrow. Curious to see what the innards look like!


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## Mcswain (Dec 25, 2016)

Can you visualize the words coming out of my mouth? Lol


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## MechanicalDVR (Dec 29, 2007)

Mcswain said:


> Can you visualize the words coming out of my mouth? Lol


Do you not see the knife blades when you open the unit?

If they were fitted into a loose connection they would have heat makes on them in the least case scenario?


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## telsa (May 22, 2015)

This is cute, as this is a virtually unknown failure mode, for a device that's practically idiot proof.


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## MechanicalDVR (Dec 29, 2007)

telsa said:


> This is cute, as this is a virtually unknown failure mode, for a device that's practically idiot proof.


Yeah man usually pretty easy to spot:










You may have to pull off the arc shield to see the contact points.


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## telsa (May 22, 2015)

MechanicalDVR said:


> Yeah man usually pretty easy to spot:
> 
> 
> 
> ...


Not quite gorilla proof.

I've found more than a few apprentices, when finally confronted with mechanical lugs, who were not aware that such set screws do not require infinite torque.


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## Mcswain (Dec 25, 2016)

That's it. The red plastic, behind it is where I believe we will find the issue! Nothing obvious in the slots. Slight discoloration but nothing the one in your pic.


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## Mcswain (Dec 25, 2016)

Didn't get any pics. Took it apart and the blades that make and unmake the contacts attached to the plastic roller/drum were the issue. Sanded them down and there was some bright copper lol they look like had a galvanized coating! 
Pretty kool! Nice to be able to fix something rather than replace it.


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