Hi everyone.

Im new to roasting. Did a few roasts on the weekend in an unmodified cornelius popper (coffeenelius?). First crack was happening at 2min and second at 4-5min so Im looking at ways to slow it down a bit.

Im looking at a couple of ideas.

One is to speed up the fan because its only running at 16V but its built for 24. I think i can increase the voltage across it by increasing the resistance that controls this (thats the resistance across the smaller heating element). So Id wanna add in a variable resistor (potentiometer/rheostat) between the circuit board and the small heating element. Higher resistance here = higher voltage in to the fan.

I Dont want to burn out the fan so Ill need a constant resistor in there too, in parrellel to the variable one. This puts an upper limit on the extra voltage, whatever I do with the the knob i cant take the fan past 24V.

Ive done a bit of maths and I need the constant resistor to be 1.5 ohms and able to take 34 watts of power. The variable resistor needs to be able to take 17 watts and needs to give me control between zero and maybe 10 ohms but it doesnt matter if it goes a bit higher.

Could this work?

Does anybody have any suggestions where to buy the bits? I could get a gang of 4 resisters (10Watts) for $2 each from jaycar but not the variable resistor. I like to scrounge electrical parts so best of all would be a tip on what to take apart (knobs from electric stoves maybe?)

Thanks,

Conan

Im new to roasting. Did a few roasts on the weekend in an unmodified cornelius popper (coffeenelius?). First crack was happening at 2min and second at 4-5min so Im looking at ways to slow it down a bit.

Im looking at a couple of ideas.

One is to speed up the fan because its only running at 16V but its built for 24. I think i can increase the voltage across it by increasing the resistance that controls this (thats the resistance across the smaller heating element). So Id wanna add in a variable resistor (potentiometer/rheostat) between the circuit board and the small heating element. Higher resistance here = higher voltage in to the fan.

I Dont want to burn out the fan so Ill need a constant resistor in there too, in parrellel to the variable one. This puts an upper limit on the extra voltage, whatever I do with the the knob i cant take the fan past 24V.

Ive done a bit of maths and I need the constant resistor to be 1.5 ohms and able to take 34 watts of power. The variable resistor needs to be able to take 17 watts and needs to give me control between zero and maybe 10 ohms but it doesnt matter if it goes a bit higher.

Could this work?

Does anybody have any suggestions where to buy the bits? I could get a gang of 4 resisters (10Watts) for $2 each from jaycar but not the variable resistor. I like to scrounge electrical parts so best of all would be a tip on what to take apart (knobs from electric stoves maybe?)

Thanks,

Conan

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