Dear Frank 1: Box shape and diameter are VERY important. At "critical speed", for a given combination of rotational speed and container diameter, centrifugal force will hold the pellets stationary against the container wall, and there will be zero tumbling and pellet wear. A machine running at say 95% critical speed will create very little abrasion, but a machine running at say 60% of critical Speed will create a great deal of abrasion effect, because of the cascading action.
2: Do you want to turn the drum/container/box for a fixed time, OR a fixed number of revolutions? 3: One could calculate the required HP, but the simplest and least costly thing is to try the 1/3 HP motor, and if it does not overheat after say 4 consecutive tests, it is good for the job. If it does overheat, then you have proven that you need a bigger motor. Best wishes, Kevin ----- Original Message ----- From: Frank Shields To: 'Discussion of biomass cooking stoves' Sent: Tuesday, February 12, 2013 2:30 PM Subject: [Stoves] Calculating the RPM Greetings Stovers, Building equipment for determining the hardness of pellets and biochar I need something to turn a 9 kg box at a speed of 60 RPM +/- 1. I have a 1/3rd HP motor that is rated at 1725 RPM Fitted with a 2" pulley attached to the motor and going to an 8" pulley gives me a shaft turning 431 RPM Then another 2" pulley going to an 8" pulley on another shaft gives me 108 RPM I plan to adjust the 108 down to 60 using a voltage regulator. Is this a good plan? And is there another factor I need to include for the weight of the box I am turning? Thanks Frank Frank Shields Control Laboratories, Inc. 42 Hangar Way Watsonville, CA 95076 (831) 724-5422 tel (831) 724-3188 fax www.controllabs.com ------------------------------------------------------------------------------ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
_______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
