Ender 5 Plus Duet 3, OUT 0 Fuse Popped

[TRATOON]

@jumpedwithbothfeet just replaced the fuse, when I start the heating process I tell it to go to 30c to test. However I get heater fault heater is slower than expected so I run pid tune using m303 h0 s75 and then the fuse pops, so something during tuning pops breaker

[TRATOON]

@jumpedwithbothfeet this is my wiring

[jumpedwithbothfeet]

@tratoon My wiring is exactly the same, even down to the plug, have you checked the heater/thermistor yet? just measured my heater resistance at the plug its reading 1.6 Ohms also at 24v

[TRATOON]

@jumpedwithbothfeet I got my resistance it is 1.65 ohms and my thermistor is showing an accurate reading

[TRATOON]

@jumpedwithbothfeet how can I troubleshoot it, will the mosfet ok if so how do I wire it

[dc42]

@TRATOON

1. If you set your multimeter to measure resistance and short the multimeter leads together, what reading do you get?
2. If you disconnect the bed heater wires from the Duet, can you measure any continuity between them and Duet ground?

[TRATOON]

@dc42 1. 0.1ohms resistance
2. I’m not quite sure what you mean, where is duet ground?

[dc42]

@tratoon said in Ender 5 Plus Duet 3, OUT 0 Fuse Popped:

2. I’m not quite sure what you mean, where is duet ground?

The VIN- terminal on the Duet is one option.

I can think of two reasons why bed heater fuse might fail
three reasons why bed heater fuse might fail

Amongst the reasons (https://www.youtube.com/watch?v=Cj8n4MfhjUc) I can think of why the bed heater fuse might fail are:

• Bed heater resistance too low. The bed heater fuse is rated at 15A, so a bed heater with a lower resistance would blow it, eventually. It would take a much higher current than 15A to blow it quickly.
• Short between bed heater and ground. [That's why I asked you to check for continuity.]
• Incorrect bed heater fuse fitted.

[TRATOON]

@dc42 the hot bed resistance is what it is supposed to be ,neither of the heater wires are continuous with vin-, the heater wires are continuous with each other not sure IF this is bad, did you send wrong YouTube video this is about Spanish Inquisition

[TRATOON]

@dc42 it is fitted with15amp fuse

[jumpedwithbothfeet]

@TRATOON we are running the bed very close to the 15amp fuse limit (24v/1.65 =14.54amp) if you don't have a ground (VIN- to heater) and you have continuity between the heater wires, and you have the correct fuse fitted, it sounds like you're pulling enough amps to pop your fuse, I`m not a qualified electrician but I believe your choices are -

1. change the bed
2. increase the resistance
3. fit an external relay/mosfet to control the bed.
4. better quality fuse (15amp)
5. use a 12v PSU

I can`t say which is the safest/easiest/cheapest way, others will chime in, I hope.

[TRATOON]

@jumpedwithbothfeet How would I wire the included creality mosfet to the duet 3?

[jumpedwithbothfeet]

@tratoon is it this mosfet?

https://www.3djake.uk/creality-3d-printers-spare-parts/mosfet-for-cr-10s

[jumpedwithbothfeet]

@tratoon check out this post -

https://forum.duet3d.com/topic/28865/how-to-wire-an-external-mosfet-on-a-mini-5-plus?_=1663941302490