Welcome! Log In Create A New Profile

Advanced

Fuse on Ramps 1.4 not sufficient for heated bed, need advice

Posted by cthzi 
Fuse on Ramps 1.4 not sufficient for heated bed, need advice
March 20, 2018 08:29AM
Hi guys!

Last year I build a CoreXY printer from scratch as part of a university project.

I have a aluminium plate as my print bed and a silicone heated bed with 12V/ 250W. My power supply has DC 12V 50A 600W. When I tried to get my heated bed to work, the fuse for the heated bed got hot and the bed shut off after about a minute. By now I know that the fuse is not sufficient for a heated bed with these specifications.

I was able to print PLA fine without a heated bed (thanks to a PEI Sheet on my aluminium plate) but now I want to start printing ABS and I need the heated bed to work.

What do I have to change on my board? What kind of fuse do I need?

Any advice is appreciated.
Thanks!

Cathleen

Edited 1 time(s). Last edit at 03/20/2018 08:31AM by cthzi.
Re: Fuse on Ramps 1.4 not sufficient for heated bed, need advice
March 20, 2018 04:08PM
For a bed of that power, you would be much better off using 24V power. Then the bed wires, bed mosfet, and fuse (if you need one) need carry only about 12.5A instead of 21A.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Fuse on Ramps 1.4 not sufficient for heated bed, need advice
March 20, 2018 07:40PM
Hi,

Thanks for your answer.

I thought about that but the heated bed is for 12V only.
Re: Fuse on Ramps 1.4 not sufficient for heated bed, need advice
March 21, 2018 03:34AM
In that case you will need to use a good DC-DC SSR (not a SSR-40DD, those are no good for this application) or MOSFET switch to control the bed heater. And very thick wires between the PSU, SSR or switch, and bed heater.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Fuse on Ramps 1.4 not sufficient for heated bed, need advice
March 21, 2018 08:25AM
Hey,

Yes, I will do that. I read about SSR yesterday and you're right. Thanks for the advice with the DC-DC SSR.
Sorry, only registered users may post in this forum.

Click here to login