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Post by rocklicker on Mar 28, 2010 16:04:58 GMT -5
OK, I expanded a tumbler to handle about 60 pounds from 30. It did have a 1/6 HP motor and was perfectly happy with it. I have been toying with a 1/3 and 1/4 HP motor. Then revco got me thinking... what is a good motor size for a large tumbler? It's got 4 big hex barrels on it.
Funny thing is, I tried it with 1/6 HP motor and it's running just fine. It runs warmer than it used to but not hot to the touch at all. The motor is under more of a load for sure. I am looking for the most efficency and motor lifespan.
I have heard of people her using 1/4HP motors and larger. Also I found that some of the larger production tumblers come with 1/4 and 1/3 HP motors... so what's a good size? Steve
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
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Post by drjo on Mar 28, 2010 17:09:53 GMT -5
Use an A/C amp meter on the motor and adjust the load til you get the rated current that is marked on the motor...that's where the motor is designed to run and will be happiest.
Dr Joe
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revco
starting to spend too much on rocks
Another Victim Of The Rockcycle
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Post by revco on Mar 28, 2010 22:24:42 GMT -5
Hahaha. I think that's up to us to define? None of us are exactly tumbler engineers here...we just pretend to be. After reading many forum posts here, I kind of took this rough relationship of poundage to power away: 12lb - 24lb = 1/12 HP 24lb - 36lb = 1/6 HP 36lb+ = 1/4 HP to 1/3 HP Some people would use less, some more. I also read somewhere on here that a commercial 40lb tumbler used a 1/3HP motor. Unfortunately, a lot of the commercial stuff I've looked at doesn't specify the motor's power...so learning from the big boys isn't a ready option. It's obviously desirable to get as close to what's needed as possible, such that motor operates most efficiently. I'd also say that it needs enough power to get through less than perfect conditions - e.g. a brand new load, a imbalanced load, ball bearing wear, etc. The advantage of DIY is that, as far as I can tell, the barrel's theoretical maximum weight is more defined by the motor itself than the barrel...who cares if a 15lb barrel weighs 16lbs+ if the power is there to drive it? I'd also point out that it's probably important to consider expansion, although in your case, you're all ready expanding and 60lbs is a LOT to work with. Dr. Joe's suggestion is exactly correct, although I would argue that many of us don't have ampmeters and multiple motors to test with. (Like me, for example!) For what it's worth, I've settled on 1/4HP for my 36lb tumbler - your test with 60lb's @ 1/6HP fully settles it.
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Post by Hard Rock Cafe on Mar 29, 2010 13:31:19 GMT -5
I'll have to test my motor: 1/12 HP and 50-60lb barrel. But it gets hot....
Chuck
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rockdewd
has rocks in the head
Member since October 2007
Posts: 605
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Post by rockdewd on Mar 29, 2010 22:35:48 GMT -5
When I expanded my 36 lb tumbler to 87 lbs the original 1/4 hp seemed to manage the load just fine but even when driving 36 lbs it ran hot as with 87 lbs. It ran that way for a couple of years then the 1/4 hp died. Seems like the bearings or bushings gave out. There were no places to oil the motor.
I replaced it with a 1/3 hp ancient used blower motor and it's running fine and less motor heat. I've got a cheap HP ampmeter. How do I check it?
I would like to buy a new motor for a more permanent replacement.
Rick
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revco
starting to spend too much on rocks
Another Victim Of The Rockcycle
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Post by revco on Mar 30, 2010 0:32:56 GMT -5
I'd defer to someone more experienced who might know for sure on these types of motors, but I'd check a single power lead going into the motor. (Both wires will effectively cancel each other in AC...so you have to make sure you only get one lead) You'd then check that amp rating against the FLA (full load amp) rating for the motor. You'd want less than 100%...preferably 80-90%. Higher than rated loads will definitely cause premature end of life.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
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Post by drjo on Mar 30, 2010 6:29:30 GMT -5
Dr. Joe's suggestion is exactly correct, although I would argue that many of us don't have ampmeters and multiple motors to test with. (Like me, for example!) NO AMP METER...NO EXTRA MOTORS!?! You MUST be kidding me!!! Go out to the barn and check again! ;D Just one motor, but add or remove weight in the barrel till correct amperage is effected. (in any other instance we would be changing pulley sizes to get the correct amp draw, but that doesn't work here). rockdewd Your amp meter would need an A/C setting 50% higher than the motor your testing (to allow for for start up surge) and is put in series with one leg of the electrical supply wiring, or use a clamp-on amp meter similar to www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96308 , you don't have to disconnect anything with it, just separate the wires so you can put the clamp around one of them. Dr Joe .
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
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Post by quartz on Apr 1, 2010 21:28:08 GMT -5
$30.00 got me a load meter at Lowes; plug the load in it, plug it into the outlet, and read amp draw or wattage per your selection.
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Post by rocklicker on Apr 2, 2010 15:56:47 GMT -5
That's a great idea quartz. I haven't made it to the hardware store yet so haven't gotten around to measuring it, but it's still running fine. The motor hasn't gotten any hotter than when I first had it going. I think a load test is in order. I'll try it adding one barrel at a time. Steve
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