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Discussion Starter #1
This is my first post and I am not very electrically inclined so please bear with me. I am building a coffee roasting machine. I already have a 2hp blower that runs at 3750 rpm. Is it possibe to add a part so that I can vary the rpm's. Maybe something like a rheostat? I am running this unit on 220 power. I believe that I will need to significantly slow down this machine.


thanks in advance.

Glenn
 

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No. Using a reostat will lower the voltage but the motor will still try to run at its rated rpm. By reducing the voltage you will be increasing the amprage wihich eventually fry the motor. I would look for a blower motor that runs the rpms you need, or try to reduce the rpms with pullys and belts if your design allows it. If the blower is attached directly to the motor this may not work.
 

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Discussion Starter #3
There are two main components to a coffee bean roaster. On is the blower so that the beans continually circulate. The other is the heating element where the temp will ramp up slowly until it hits approx. 460 degrees.

If a rheostat is out and I do understand why, what type of fan or blower can I use to circulate air within the beans where I can vary the speed of the air. Without buying a number of fans or blowers, I am not able to determine how much air movement I will actually need. This is partially due to varying the amount of beans per roast.

Any help will be appreciaited.
 

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Discussion Starter #5
The fan circulates the heated air so that the beans are constantly moving (be it slowly) . This avoids individual beans from burning.

Thanks
Glenn
 

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google search = "coffee roaster fans, blower"

lots'a stuff
 

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gsa, Google up Vari-speed. There are a number of controllers for industrial motors.
 

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I have done this myself,.... Use a "VARIAC". this will vary the voltage going to the motor and thus the vary the RPM... What are you using to make the green bean machine... I have used an old toaster with great sucsess. Later
 
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