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Large Power Supply Question

Posted by Tophster 
Large Power Supply Question
April 24, 2018 12:15AM
I am in the process of designing a printer and I am needing a large heatbed. I was able to find an 18"x18" heatbed that is 12V but draws 44 amps. So with that and the board I am using, Duet Wifi, which draws 5 amps I am wanting to use a 60 amp PSU to have a buffer. Will the PSU that I have linked work as a supply? I am not sure exactly how all this works because I new to it but did some research, I am just wanting to make sure that what I am planning will work out.

Thanks.

Link to the PSU: PSU LINK
Re: Large Power Supply Question
April 24, 2018 01:23AM
Don't do that. Heaters don't care if you give them AC or DC, so why use a regulated supply to drive a heater? You'll need enormous cables to handle the current and connections will be a problem. Get a line powered heater and switch power to it using an SSR. That will allow you to use much thinner, more flexible wire, a much smaller, cheaper, and quieter power supply (use 24V, not 12V), and connections will be easy.

I don't know what you're planning to use for a bed, but as a point of reference, my printer's 300x300x8mm cast aluminum bed has a 750W heater and gets up to ABS print temperature in about 4.5 minutes. That's a bit over 0.5W/cm^2. If you use less power it will take longer to heat up. If you aren't going to print ABS or PC or other high temperature materials, you can use less power. The SSR that is switching power to that heater doesn't even get warm and operates without a heatsink.

I have used Meanwell LRS-200-24 power supplies in 2 printers and they are great. No fan, very reliable, and more than enough power. They are pretty small and cheap, too. $32 shipped, via ebay, from a US source (no waiting for that boat from China!)

Edited 1 time(s). Last edit at 04/24/2018 01:29AM by the_digital_dentist.


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Large Power Supply Question
April 24, 2018 02:14PM
The best source for the bed that i found was an 18”x18” 12V silicon heat mat. The build plate is 20”x20” for the printer I’m making. So I need it to be at least 18”x18”. If you know any 24V options that would be great.
Re: Large Power Supply Question
April 24, 2018 02:26PM
I agree with digital_dentist, for that size bed I would use AC mains power despite the additional safety precautions needed. See [duet3d.dozuki.com].

Ask either Keenovo or Shenzen Ali Brother Technology to make you a silicone bed heater to your own size, voltage and power specifications. It doesn't cost much. Keep the heater a little smaller than the build plate, to leave room for fixings around the edge. This one [www.aliexpress.com] may be close to what you want.

Edited 1 time(s). Last edit at 04/24/2018 02:28PM by dc42.



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: Large Power Supply Question
April 24, 2018 03:18PM
Use a dell server power supply. Conversion link below

Dell Poweredge 2800 930W PSU 12V@75.7A

Edited 1 time(s). Last edit at 04/24/2018 03:30PM by madmike8.
Re: Large Power Supply Question
April 26, 2018 03:32PM
I like the mains heated bed and currently have a 120 volt heater on my 200 mm x 200m Cartesian. I am building a 330mm delta and all I have found so far in that size is 220 volts. 120 volts are not popular except in the US. Any suggestions for a source?
Re: Large Power Supply Question
April 26, 2018 04:53PM
Quote
cwaa
I like the mains heated bed and currently have a 120 volt heater on my 200 mm x 200m Cartesian. I am building a 330mm delta and all I have found so far in that size is 220 volts. 120 volts are not popular except in the US. Any suggestions for a source?

Yes, see my earlier post.



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: Large Power Supply Question
April 27, 2018 09:27AM
Thanks!
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