He3D Delta DLT 180: Power In Plug Melted / Glowing Orange!

Please see attached picture.

The power in green plug has melted and the wire inside was glowing orange/smoking.

- Heat bed installed
- Power supply set to 12v

Prior to turning on the printer, it had completed a 2 hour print. After that, I tried to print again and noticed the smoke / orange glow.


Any ideas what I can do? Does the board need to be replaced? Is it salvageable (safe?)?
Any ideas why the power in was overheating?

Thanks

Edited 1 time(s). Last edit at 10/15/2016 02:00AM by carlol.

This a common issue and the reason why lots of people are using relays to power their beds. The whole power supply circuit for the bed is undersized on the ramps (connectors and mosfets). Measure you the actual power use of your board and compare it to the ramps ratings.

Since the boards are so cheap now, I would replace it to be on the safe side. Or try this [www.tindie.com]

Looks like a melted connector only. Did you tighten the screw well? Was the wire clean?
Actually may be the source of the heat was a bad solder joint.

Those connectors should be rated around 12-15A. You should be OK if your bed is taking less than that.
If you can solder then you can try to replace only the connector.

Edited 1 time(s). Last edit at 10/16/2016 10:42AM by hercek.

Thanks everyone for your responses. I've ordered a new board and a relay and will try to wire that in.


Does the attached relay wiring look OK? Also this relay is for 10A, but the heatbed I think may pull up to 12A. Is this a problem?

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carlol
Does the attached relay wiring look OK? Also this relay is for 10A, but the heatbed I think may pull up to 12A. Is this a problem?

Yes. It may work for some time but it will fail sooner. If you are in a bad luck it will catch on fire when it fails.

You need components which are rated for more current than the maximum current your bed can take.
E.g. my connectors are rated for 12 or 15 A (not sure about the exact kind I have), FETs are for about 40 A and the bed can take at most 11 A (at 12 V).

Quote
hercek

Quote
carlol
Does the attached relay wiring look OK? Also this relay is for 10A, but the heatbed I think may pull up to 12A. Is this a problem?

Yes. It may work for some time but it will fail sooner. If you are in a bad luck it will catch on fire when it fails.

You need components which are rated for more current than the maximum current your bed can take.
E.g. my connectors are rated for 12 or 15 A (not sure about the exact kind I have), FETs are for about 40 A and the bed can take at most 11 A (at 12 V).

Thanks, I scrapped this relay. Someone suggested even a solid state relay so I have ordered an SSR-40 DD.

I also realized one of the likely causes of my original overheating problem was the wire I used, too thin of a gauge (amateur error yes... I am new to this). So will replace all to 14 awg wire with15 ampacity (or maybe even 12 awg/20A).

Quote
carlol
I also realized one of the likely causes of my original overheating problem was the wire I used, too thin of a gauge (amateur error yes... I am new to this). So will replace all to 14 awg wire with15 ampacity (or maybe even 12 awg/20A).

Probably not. If the wire would be the source of the heat then it's isolation would be scorched or at least the heat would deprive the wire isolation from elasticity. The isolation would break if you would bend the wire.

It looks like a bad solder joint or production defect on the connector itself. (Assuming that the connector you have there was really rated at 12 A or more. Maybe you had some non-typical connector which looks like the 12-15 A ones but was rated less than 12 A.)

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carlol
Thanks, I scrapped this relay. Someone suggested even a solid state relay so I have ordered an SSR-40 DD.

I am sorry, but that is a terrible choice of SSR. See [duet3d.com] for good DC-DC SSRs.

Quote
carlol
I also realized one of the likely causes of my original overheating problem was the wire I used, too thin of a gauge (amateur error yes... I am new to this). So will replace all to 14 awg wire with15 ampacity (or maybe even 12 awg/20A).

Much more likely is that either the terminal block screws worked loose, or that the connector was of poor quality.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].