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MK3 vs. MK2.5 hotend heater element  

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Jimbo70
(@jimbo70)
Estimable Member
MK3 vs. MK2.5 hotend heater element

I know the MK3 is 24 volts and the MK2.5 is 12 volts but are the heater elements (the tube-like thing that fixes to the heater block) the same?

I suspect they are the same and the control board limits the amount of current.

 

Posted : 24/03/2020 2:55 pm
vintagepc
(@vintagepc)
Member
RE: MK3 vs. MK2.5 hotend heater element

They are not. See the replies to your other post instead of posting duplicates. 

Posted : 24/03/2020 2:58 pm
Jimbo70
(@jimbo70)
Estimable Member
Topic starter answered:
RE: MK3 vs. MK2.5 hotend heater element

@vintagepc

sorry, I should have stated my question differently. I have a heater but I do not know if it is for a MK3 or MK2.5. How can I tell the difference? Is the resistance different?

Posted : 24/03/2020 3:02 pm
DJ
 DJ
(@dj-6)
Trusted Member
RE: MK3 vs. MK2.5 hotend heater element

Yes the resistances are different. I’m not where I can measure one myself however if you have a multimeter you can identify which one you have. I presume the two heaters are unconnected.  Measure the resistance of each separately and record those readings. For simple identification purposes these don’t need to be extremely precise. The MK2 series (including MK2.5) powers the heaters using 12 volts. The MK3 series uses 24 volts. Assuming both heaters have red sleeves on their wires near the heater end then both are 40 watt heaters. From ohms law we can figure out if 40 watts using your measured resistance requires 12 volts or 24 volts:

Volts = sqrt(40 watts * Resistance in ohms)

DJ

Posted : 24/03/2020 3:25 pm
Neophyl
(@neophyl)
Illustrious Member
RE: MK3 vs. MK2.5 hotend heater element

From what I can tell from a quick google search

 2-6 ohms it's a 12V cartridge. The 24V ones will be more like 15-20 ohms. 

 
Posted : 24/03/2020 3:28 pm
Jimbo70
(@jimbo70)
Estimable Member
Topic starter answered:
RE: MK3 vs. MK2.5 hotend heater element

@neophyl

thanks, I looked everywhere on Google for the past few days and could not find the answer.

Posted : 24/03/2020 3:34 pm
vintagepc
(@vintagepc)
Member
RE: MK3 vs. MK2.5 hotend heater element

Yes, they are 40 watt heaters. Current limiting is not a control board feature, it's caused by the heater resistance.

P = VI, I = V/R, so: P = V^2/R (Or, R = V^2/P)

P = 40

At V = 24, R ~~ 14.4

At V = 12, R ~~ 3.6

 

Posted : 24/03/2020 4:03 pm
Jimbo70
(@jimbo70)
Estimable Member
Topic starter answered:
RE: MK3 vs. MK2.5 hotend heater element

thank you, 

I now have the information I need. I find that I do not have a heater for my MK2.5 - I only have MK3 heaters.

 

Posted : 24/03/2020 4:40 pm
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