Air Pop with Transformer

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
nickthorpie
Posts: 38
Joined: 8 years ago

#1: Post by nickthorpie »

So Ive started roasting in a pop corn machine and as you can expect, its too hot.
I'm targeting a 150°C chamber temperature, but when plugged directly into the wall I get upwards of 185°. Ive managed to get to almost 165° when using a few extension cords, a power bar, and blowing a fan into it.

Are there any transformers on the market that would plug into a 120v outlet to lessen the heat output?

The outsides are almost overdeveloped before first crack! Help!

billsey
Posts: 98
Joined: 9 years ago

#2: Post by billsey »

I believe what you are looking for is a variac. It allows you to adjust the power up or down.

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Almico
Posts: 3612
Joined: 10 years ago

#3: Post by Almico »

Ideally you want to separate the fan from the heating element. This way you can keep the beans spinning while controlling the heat on its own. Control the fan with a dimmer switch and the heat with a 10-15 amp variac. Do not use a dimmer for the heat. The wattage is way too high.

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AssafL
Posts: 2588
Joined: 14 years ago

#4: Post by AssafL replying to Almico »

Why would you not use a suitable rated "dimmer"? Both the heaters on my Quest M3 and the heaters in the GS/3 are controlled using SSR - basically a dimmer circuit (PID - it doesn't matter - one could set it on PWM instead of PID) - where the zero crossing point is detected by the SSR (usually the DIAC or fancy TRIAC do the zero crossing detection...).

Variacs are awesome - but big and expensive.

I would assume a 1500W or larger dimmer should work... (but I never tried it though..)
Scraping away (slowly) at the tyranny of biases and dogma.

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Almico
Posts: 3612
Joined: 10 years ago

#5: Post by Almico replying to AssafL »

Dimmers usually control lights and most are rated well below 1500W. If you can find one to handle that much current, then it would work. I was just sending a warning out there not to hook up an old dimmer switch found laying around the house to a 1500W heating element.

An SSR/contactor set up controlled by a small 1M potentiometer would be great too. Still not cheap, but better that a beefed up light switch.

Something like this but rated for 120V: