Bed connector burnt - DUET 0.6

Hi,

I am building Core XY 300x300x300. I am using DUET 0.6 from RepRap Ltd.

I am using 24V, 20A power supply. All the components are 24V. I bought 24V 300W Silicon heater from Aliexpress. Today I set the temperature to 100deg. It took 20mins to reach only 90deg. After that when I checked the DUET board, the bed connector is burnt.

Please find the attached image.

As per the DUET 0.6 recommended current, it should be 10A. But I hope I have given more than that. 300W/24V=12.5A. After burnt only, I cross checked the DUET recommended bed current. Now I can changed the connector.

But, as per DUET 0.6 wiki, 'The board is comfortable with 10A bed heater current, but not much more. The weak link is the PCB trace on the top side of the board that connects the Power In V+ and Bed Heater V+ terminals. If you want to use a bed heater that draws more than 10A, solder a thick wire between those terminals on the back of the board.'

This means that I can connect a 1.5sq.mm thick wire (stranded wires) between those terminals directly? Will it withstand that much current?

Or any other way to reduce the current to the bed, so that it runs safetly for a long time?

I am planning to cool down the Electronics by 24V 60x20 cooling fan. Any other precautions to be done?

The Electronics and wiring will be enclosed below the printer.

A burned terminal block is a sure sign that the screw was not tightened properly, or (more likely) that it worked loose. Best advice is to crimp ferrules on the wire ends before inserting them into the terminal block, and also to check the tightness of the screws regularly during the first few hours and days of use, to allow for any creep in the wires caused by the heat. Do this with both the VIN and the bed heater terminals.

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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].

Thanks for the response. But, is it ok to use the bed wires (300W) as it is? Or should I connect Bed V+ and Power In V+. That is the confusion..

Thank you always for the answers you are giving to us.

As it is a Duet 06 and the specified bed current is significantly over 10A, I recommend you connect those two terminals using a thick wire on the back of the board as a precautionary measure.

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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].

Ok. Thanks. Finally, I got one more Topic which is similar to my case which shows how to jumpering the tracks between Power in and Bed heater.

[forums.reprap.org]

Edited 1 time(s). Last edit at 07/02/2017 04:04AM by selva_tvi.