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Melted power terminal

IanJohnson

Melted power terminal
October 07, 2012 01:50AM

Registered: 12 years ago
Posts: 132

I lost power to my Sanguinololu. I thought the cable might have a break or something, and when I took it out I found that the block had melted-

img_5430-e1349588729785.jpg

Is there something I could have done to cause this? In addition to the motors, it runs a heated bed, LEDs, an electronics fan, extruder fan, and gcode controlled nozzle fan (using Nophead's hack with the logic level MOSFET)..

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Dabble

Re: Melted power terminal
October 07, 2012 04:09AM

Registered: 13 years ago
Posts: 21

Looks like a bad connection between your power wire and the power connector. A bad connection will mean that there is high resistance and hence heat will be generated

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jamesdanielv

Re: Melted power terminal
October 07, 2012 04:12AM

Registered: 13 years ago
Posts: 1,797

probably a bad contact. if possible i would replace that contact, go to a radio shack to find the terminal, probably best next time you tin the wires. (solder the end of wire making it tinned to make it resistant to the elements.)

Edited 1 time(s). Last edit at 10/07/2012 06:32AM by jamesdanielv.

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brnrd

Re: Melted power terminal
October 07, 2012 09:41AM

Registered: 13 years ago
Posts: 1,780

Soldering the ends of the wires is not a good idea for the screw terminals. You want to make as much contact as possible and soldering reduces that. It's best to keep the ends bare.

Also, I think that the terminals for the Sanguinololu is inadequate for a heat bed. The solution was posted by nophead in this thread: [forums.reprap.org].

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jamesdanielv

Re: Melted power terminal
October 08, 2012 11:12AM

Registered: 13 years ago
Posts: 1,797

the point of failure here was a contact connection,not the MOSFET. probably copper wire, that when it was heated oxidized,and formed a resistor. if you don't want to tin the wires, then use tin wire at the proper gauge.

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xiando

Re: Melted power terminal
October 08, 2012 12:28PM

Registered: 11 years ago
Posts: 477

Hmm... what's that screw terminal rated for? Looks to me like a 0.1" spaced Phoenix Contact rt-angle PCB mount screw terminal...rated for about 6A. It might *take 10A for a little while, but afaik, those aren't rated for the current you're drawing at steady state, not even commenting about the surge during MK1 heatup.

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IanJohnson

Re: Melted power terminal
October 08, 2012 12:58PM

Registered: 12 years ago
Posts: 132

I had been thinking of switching it out with an Azteeg X1, so this was a push to actually do that.

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royco

Re: Melted power terminal
October 08, 2012 01:29PM

Registered: 12 years ago
Posts: 156

@Ian You're good with the X1, The connector I use on it is rated for 18Amps per pin. @digikey

But like others have mentioned, keep a good contact with the wire, tug it from time to time to check if it has loosened.

Thanks.

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brnrd

Re: Melted power terminal
October 08, 2012 10:09PM

Registered: 13 years ago
Posts: 1,780

I've had no problems with the Azteeg X1. Even the Mosfets stay cool to the touch with the heatsinks installed. It even comes with fan control.