220v Extruder?

CJ.BRAVO

Hey there,

I've got a customized extruder (not a typical heating block) which needs non-cartridge heating elements.

The suitable elements run on 220v.

Can I connect them to the duet the same way I would connect a 220v bed heater ?

Using a SSR and connecting to the E0/1 heaters ?

Thanks

gtj0

Safety concerns aside, don't see why not. I know the default PWM frequency for a bed header is 10hz which is fine for SSRs but not sure what the default is for an extruder heater. You may have to use M307 to make sure the SSR is switched at a reasonable frequency.

Connection wise, that would be fine. Configuration wise I'd want to confirm that you can run the hot end PID loop at a low frequency like the bed, and that it doesn't affect the response of the control loop. And safety safety safety stuff ofc.

CJ.BRAVO

@bearer

what am I looking for here? specs of the heating element or am I testing the ssr ?

dc42

That should be OK using a zero crossing DC-AC SSR to switch the heater, but set the PWM frequency to 10Hz.

CJ.BRAVO

@dc42 said in 220v Extruder?:

zero crossing DC-AC SSR

ok cool,
how to change PWM frequency ? and why actually ?

deckingman

@cj-bravo

Use F10 here
https://duet3d.dozuki.com/Wiki/Gcode#Section_M307_Set_or_report_heating_process_parameters

gtj0

@cj-bravo said in 220v Extruder?:

@dc42 said in 220v Extruder?:

zero crossing DC-AC SSR

ok cool,
how to change PWM frequency ? and why actually ?

Check this thread out for the "why"...
https://forum.duet3d.com/topic/11408/ssr-brands

@cj-bravo said in 220v Extruder?:

what am I looking for here? specs of the heating element or am I testing the ssr ?

My concern, possibly unfounded, would be that because you need to run the PID with a low PWM frequency you might get oscillating temperature if the hot end has a faster thermal response than the control loop as the thermal mass of the heater element/heater block is so small, or possible due to the coarse resolution the low frequency would result in. Could also be just fine.

CJ.BRAVO

Hey,

so had some problems getting the 220v heater to work and after many trials and head scratching it turned out that the problem was the cables I used to connect all the components together.

At first I used some cable that I was told is for 12v, to connect the duet to the SSR. didn't work so I cut some cable from an old heating cartridge and it worked...

This was actually the 2nd time I had trouble with heaters and cables after I had some issues with a 12v heater connected to the duet but I used a 220v cable and it faulted. switched to a different 12v rated cable and it worked.

does all of this makes sense?

now it works even withouth the F10 (pwm) configuration.

thanks ya all

Cable voltage ratings are usually related to the insulation properties; you do not want to use a cable that is not rated for mains voltage for your mains voltage heater, especially not in non stationary installation.