Multiple power source/multiple heater setup

All, I had asked some questions about non integrated heaters, and I think it is a bit too advanced for me right now.

I am trying to make a printer with a 500mm x 500mm print area, that can print ABS.

So obviously I need some serious heat for the bed.


Here is what I am thinking, and I wanted to see if I could get some feedback before I buy everything to do this.

My plan is to use two heaters:

24V 17A for the 11amp input to Ramps for the heated bed.

12V 20A for the 5amp input to Ramps for all else


I want to use somewhere between 2 and 4 24V kapton type heaters to the underside of a sheet of 500mm x 500mm aluminum sheet, which my glass will sit directly on top of, OR, I may just use a 6mm sheet of aluminum as my print bed.

I will use a blade fuse between the 24V PSU and the Ramps 11 amp input.

Does this sound like it will work?

Thanks!

At that size you should seriously consider running the heated bed off of AC.

[www.omega.com]

[www.omega.com]

All you need is an SSR and a heatsink for it. They're pretty cheap on amazon.

I drive 12x12 and 9x9 heated beds that way now with zero issues.

---

- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

akhlut Wrote:
-------------------------------------------------------
> At that size you should seriously consider running
> the heated bed off of AC.
>
> [www.omega.com]
>
>
> [www.omega.com]
>
> All you need is an SSR and a heatsink for it.
> They're pretty cheap on amazon.
>
> I drive 12x12 and 9x9 heated beds that way now
> with zero issues.


Thanks, I know you are right, I'm just not sure I understand how to use the SSR to do this.

So I did some reading up on SSR and I THINK I understand now.

The idea would be to use the SSR as a switch to use the output from the RAMPS lower voltage as a switch to turn on and off the 110v heater.

I'm assuming I would need to use a SPDT relay for this and just have on and off.

What I'm not quite clear on is the way I would connect this.

I suppose I would send the outputs ( + and -) from ramps to the switch, and run a connection from 110 + to the relay, and 110 a to the heater, and run the output if the relay to the + of the heater?

Does that sound right?

Also, I've never shopped for a Relay before, so I went to digikey and I'm a bit lost on what relay I need as there are so many config a and specs.

Can anyone help me out with getting the right relay?

Thanks!

No, the MOSFET on the RAMPS board directly controls the SSR.

The + and - leads from RAMPS connect directly to the SSR. Polarity must be maintained.

Wire the neutral lead to the heated bed and the hot lead to one side of the SSR. A jumper then comes off of the other SSR terminal and goes to the heated bed.

Very simple.

Auber Instruments carries SSR's and the appropriate heatsinks.

[www.auberins.com]

[www.auberins.com]

[www.auberins.com]

It's a good starting point. The 25A SSR should be more than enough.

---

- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]