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silicone heater

Posted by npm1 
silicone heater
March 11, 2019 01:59PM
Hi,
I am looking to upgrade my heated bed to a 220v 200w 200*200mm silicone heater, would the EinyRambo support this mod. Would i able to put in a 20a fuse for both the motors and heaters rather than the standard 15a and 5a fuse.

Or would I need an ssr/ mosfet




Please help ,
Re: silicone heater
March 11, 2019 07:29PM
You cannot control a mains heated bed directly from a EinyRambo

You need a SSR to control a mains powered device.

sure you can put 20a fuses in, you could also put nails in the slots and it will work, but not as a protected device. Instead of the fuses blowing, something else much more expensive will happen such as burnt controller, or a burnt down house. IE do not play with the fuses!
Re: silicone heater
March 12, 2019 09:43AM
the heater i have is 220v 200w 200*200mm, it worked like plug and play under the duet wifi , with no ssr or mosfet, it is a heater with standard sheathed power cables and thermistor, purchased from China thanks aliexpress.

Would the einsyrambo work with this heater, especially since the heater isn't AC, its actually DC.
Has the EinsyRambo got the same power delivery capabilities as the Duet Wifi, would updating the fuse help this heated bed.

In addition to this, I've been running the 220v 200w heater with a 12v power supply, would the using a 24v power supply work well with this heater...

Truth be told i have a 3d printer with this silicone heater attached, it works well out of the box with the duet wifi but, sadly i am having issues i.e. lack of consistent bed leveling on the duet, so i went ahead and purchased the einsyrambo which will hopefully resolve this issue...
the question is whether its worth buying a mosfet for extra security and peace of mind on the einsy rambo...

Or should how well does the einsyrambo match up to the duet wifi i.e. the bed heater

Edited 1 time(s). Last edit at 03/12/2019 10:53AM by npm1.
Re: silicone heater
March 12, 2019 12:40PM
Quote
npm1
the heater i have is 220v 200w 200*200mm, it worked like plug and play under the duet wifi

Although I'd love to say that the Duet WiFi can drive a 220V bed heater directly, it's not possible. Assuming that the bed heater did heat up to reasonable temperatures, either it must have been a low voltage heater, or you must have used a DC-AC SSR.

If you were using it successfully with a 12V PSU, perhaps it is a 12V heater? In which case, do not use it with a 24V PSU.

Your bed levelling issues are not the fault of the Duet, they suggest that your Z probe is not returning good data and/or a problem with the mechanics of your printer. Changing the electronics will not help. What sort of printer is it, what sort of Z probe are you using, and what is the bed made of?

Edited 2 time(s). Last edit at 03/12/2019 12:42PM 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: silicone heater
March 12, 2019 03:59PM
Quote
npm1
...would the EinyRambo support this mod. Would i able to put in a 20a fuse for both the motors and heaters rather than the standard 15a and 5a fuse.

Sizes (values) of fuses are typically selected in order to protect wires and connectors, so they do not get warm enough to become a fire hazard.
So you can NOT simply replace a fuse, with a larger (higher number) fuse, and expect everything to be fine. Especially if going from 5A to 20A.

If you need to control something with a load of 20A, then you need to use wire, fuse, connector AND mosfet/relay/SSR that is designed to handle 20A


For instance: A PCB wire that is designed to be able to handle 5A without getting warmer than "room-temperature + 20*C" , so such a PCB wire will typically stay below 50*C. 50*C is fine, and nothing will overheat, not even your finger, when you test to feel if it is warm.
My PCB design software tells me that a 1.7mm thick PCB wire will carry 5A, and will stay at "room temperature + 20*C"

If you apply 20A to such a PCB wire, then my PCB design software tells me, that this 1.7mm PCB wire is now a "room-temperature + 291*C" wire.
Anything at 300-320*C - is a fire hazard!!!

So you can NOT simply use a larger fuse, and think everything else will still just be fine, and will be able to deal with the higher currents. They will NOT. They WILL heat up - significantly.


Just another fyi: My PCB design software tells me that in order to easily deal with 20A, then a PCB wire should be 6.5mm wide.
Re: silicone heater
March 12, 2019 04:05PM
Quote
npm1
Truth be told i have a 3d printer with this silicone heater attached, it works well out of the box with the duet wifi

How is this heater connected to the duet WiFi board?

Do you have a picture? Or a simple diagram?

As you can tell from the response so far, we are lacking some kind of information, in order to fully imagine how you have got this silicone heater to function together with the duet board.

So how are these things connected?
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