Another 12" trommel build/rebuild

[akflyer]

A buddy gave me a trommel he had been given and as far as I am concerned its just a pretty good head start on a new trommel.

It has a 120V motor on it now that's single belt drive to the drum and its spinning it at around 60 RPM. YIKES! It also has a crude and HEAVY hopper on it. I will probably just keep the drum and frame and redo everything else.

I am torn between going gas powered and keeping it 120V and running off a generator. If I use a generator I can run a long cord to it and keep the noise maker away from me, however, I am not fond of standing in water puddles running stuff that's plugged into an outlet.

So, if I go gas do you think 3HP would be enough for a trommel this size or should I go for the 6 hp. Weight difference is about 12 pounds?

Spit balling numbers if I run the gas engine at 2500 RPM which is the max TQ for these 2 engines I would be spinning the drum at about 18-19 rpm. I could throttle up and down from there or change the # of teeth on one sprocket. The plan for gas would be a clutch on the engine turning a chain to an 84 tooth sprocket, that drives the shaft turning a 2" pulley to a 6" pulley that would turn the shaft from a 2" pulley to the 12" drum.

I would think that the 3 hp engine would be more than enough to run a 12" trommel geared down this low but I only want to have to build the mounts once. Ya'll have any ideas on it?

Oh yeah, this mining crap is highly addicting and a great way to spend countless hours researching and designing and building during the long cold winters here LOL.

 

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[dredgernaut]

I would think 3 hp should be fine. if you go gas

 

[akflyer]

one more thing.. any preference on the belt to the drum. Vee belt or serpentine type belt? Just planning on using an idler on a spring to put tension on the belt to the drum. So I have Vee belts on the intermediary pulleys and serpentine to the drum in the plans right now.

 

[dredgernaut]

I have a single v-belt straight from drum to shaft pulley with a tensioner pully to remove slop , never had an issue yet , my 6 hp has a 6 to 1 gear reducer built in. so im kinda cheating. lol

 

[akflyer]

That works for me. I didn't figure it would take much tension / friction to turn one. I have been drooling over several of the trommels that have been built here and figure this is the place to bounce ideas off people instead of just throwing dollars at crap that has been proven to not work. By the spring I should have a full arsenal or tools to prospect any type of ground I want from high bankers to dredges to a couple trommels. At this rate I will have to build a shop just to store all the toys!

 

[arizau]

First a disclaimer...I am really not mechanically nor electrically inclined and as you know "a little knowledge is often dangerous".

Have you thought about a 12v gear motor? I really don't know much about them but in my mind a 12" trommel should not need too much torque to turn when loaded so maybe a small(ish) one. A battery or your generator with an inline inverter for power assuming my idea is viable(?).

Good luck.

 

[akflyer]

I have a couple 12V geared motors on the way as well but not sure how much TQ will be required to run the trommel. If I can go 12V and run it off an onboard 30 amp power supply that plugs into a nice little quiet generator I might go that route. I have a 12V motor on my 8" trommel now with a PWM speed control to dial in optimum RPM for material that's being run.

I have the 79cc predator engine (3hP) on order now as well and if I don't use it on the trommel I can put it in the daughters go cart. I would rather have extra options sitting in the garage waiting to be used than to have the build come to a stand still waiting on shipping in parts LOL.

I wonder if the vibrations from the gas engine would help the material running through the trommel and feeding from the hopper or do you think that would be mute point. I know dialing in the waterflow is key, but the extra vibration might help as well

 

[arizau]

I think slope and water are the important considerations. They work together in the sealed section of the trommel assuming that is part of your design. Feed can overwhelm the system so you are going to have some trade offs as far as volume vs. efficiency IMO.

 

[russau]

akflyer if you do go with the gas powered generator put a ground fault receptacle in place of the 120 v 20 amp outlet to prevent any electrical shock and drive a ground stake with a number 10 ground wire in to ground that gen !!!!!!!!!! nd a "low tone" muffler would be a great option to keep that thing quieter!!

 

[akflyer]

Customer fab jobs kept me from working on the trommel last hitch home. I did however get in all the parts and pieces, 12V geared motor, pulleys, skate wheels etc to be able to get back to work on it. The 180 watt geared motor from ebay is sweet and very quiet! Once I get it all together I will put the amp meter on it and see how much juice it is pulling. I might have to stop taking on customers jobs so I get enough time to get my own projects done before spring hits!

I see a lot of these threads go dead so just dropping in here to say the dream is still alive and being worked as time allows.