quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,339
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Post by quartz on Nov 28, 2019 23:18:27 GMT -5
I've cooled a couple air over motors by putting a car alternator fan on the shaft, might have to tack or drill and tap for a couple small screws to attach a shaft collar on to hold/drive it. You need to be attentive to direction of rotation, not all alternators turn the same way.
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Post by knave on Nov 28, 2019 23:43:19 GMT -5
Video of motor. Took a lot of force to stop it, start up torque galore. Runs on hot side not loaded IMO, under 200F. Max temp is 276F. Want to do a small computer fan. Like this motor a lot. Video is hyper sound sensitive. knave, what are those clicking noises when it rose back to speed ? jamesp I wonder if it was some small grit in the new ball bearings that showed up after the max torque test? Or does it do it every time? Hard to tell from the video, as you say the noises are amplified.
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jamesp
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Member since October 2012
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Post by jamesp on Dec 3, 2019 11:27:49 GMT -5
There is something wandering around in one of the motor bearings for sure knave. You can lean the motor over when running and the 'particle' seems to get in the bearing for a few seconds and then go away. It runs quiet in all cases after 60 seconds. May be a piece of plastic, not sure.
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Post by knave on Dec 3, 2019 11:37:14 GMT -5
It’s kind of common for new motors to have a couple different sounds while being broke in. Usually they go away after a few hours of runtime. Hopefully this one does. Can’t wait to see the build!
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jamesp
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Member since October 2012
Posts: 36,154
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Post by jamesp on Dec 3, 2019 11:37:17 GMT -5
The fan mounted nicely and added .2 amps to the 1 amp motor. The fan cools the motor from 190F down to under 100F at no-load. This should improve conductivity, life and therefore efficiency. Especially under load. Benefit will be a resulting source of warm air blowing directly over barrels for freezing temperatures. Especially under load.
Video camera has hypersensitive microphone.
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jamesp
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Post by jamesp on Dec 3, 2019 11:39:42 GMT -5
Guessing it is break in noise knave.
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Post by knave on Dec 3, 2019 11:43:26 GMT -5
What is the temp rise of the air through the motors?
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Post by knave on Dec 3, 2019 11:53:54 GMT -5
1.2A x 120V = 144P (watts) 144 x 3.41214 = 491 (btu/hr)
It all gets converted to heat in the end, some in shaft friction, some in rocks tumbling, most in the motor windings.
Just for kicks another formula is CFM x temp rise x 1.08 = btu/hr
Edit: I should save my mumbo jumbo lingo and focus on the rocks, but this is fun to me also...
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jamesp
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Post by jamesp on Dec 3, 2019 13:24:37 GMT -5
What is the temp rise of the air through the motors? The wife's shop has accurate ambient air readings. I have accurate thermometers. Time to measure some temps ! Wish I could add a load. In time. These two formulas are interesting, especially the one with cfm. The little fan is faster than most with a bit higher amp pull at .2 amps. Ebay fan: This is an Ultra Strong and high flow rate AC 120mm Fan and you will be amazed by the amount of wind it blow! Ideal for computer cooling system ,any other kinds of cooling or help your space be full of fresh air, and you won't be disappointed. Must be careful for the blades as it spins in very high speed! This item provide two pieces Silver Metal Grill on the fan back side for safety. Specification Model: 12038 axial fan Bearing: Double Ball Speed:2600/3000 RPM Airflow: 120CFM Noise Level(max): 35/45dBA Power Connector: Wire length:almost 4-feet Rated Voltage: AC 115V Operating Voltage Range: 100 - 130V Input Current: ( max) Input Power: 12.5/15W FAN size: 120mm x 120mm x 38mm(" x " x 1.5") Item weight: 650g () I put an open end box over would-be barrels to check the temp rise of 7F, 61 to 68F for an estimate:
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jamesp
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Post by jamesp on Dec 3, 2019 13:27:46 GMT -5
Can it be called a power plant ?
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Post by knave on Dec 3, 2019 13:45:13 GMT -5
Can it be called a power plant ? Hahaha! That’s good... most likely explanation is cfm is reduced due to being face mounted on the motor, and also some recirc of the heated air. Thats a good one, lol.
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Post by knave on Dec 3, 2019 13:52:22 GMT -5
Give ya $3 if you can stop the shaft with your fingers. ......so did you pay up, and give yourself $3??
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jamesp
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Post by jamesp on Dec 3, 2019 14:04:26 GMT -5
Can it be called a power plant ? Hahaha! That’s good... most likely explanation is cfm is reduced due to being face mounted on the motor, and also some recirc of the heated air. Thats a good one, lol. A better fitting cardboard box should make it possible to tumble in some darn cold weather without over heating during the day. The heat is generated regardless from the motor anyway, why not use it. Just happened to be blowing in the best direction. Surprised that it cooled the motor as much as it did. It was by far the hottest running air-over without air-over motor I ever used. Made me curious if it was the slow speed that made it hot. The motor is crammed with copper windings. Heavy thing. Must have been $$$. Hope to drop the shaft off at the local machine shop for the 17mm hole today. Lol, the owner's name is Allen Head, spelled just like the bolt type. Thought he was messin with me about his name when I first met him. I have a current clamp somewhere on this farm.
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jamesp
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Post by jamesp on Dec 3, 2019 14:14:36 GMT -5
Give ya $3 if you can stop the shaft with your fingers. ......so did you pay up, and give yourself $3?? Yep, lost that bet lol. If asked to stop with just thumb and forefinger it would have been a real challenge for average grip folks. For 1 amp I am happy. It will be geared up though, from 17mm to a 1.5 inch shaft. 17mm to 37 mm = 2.2:1 up ratio
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Post by knave on Dec 3, 2019 18:09:48 GMT -5
At work today I saw a motor like this and noticed it has a separate fan for cooling the air over motor. Between the motor and blower housing is a small shaft mounted axial fan blade. Just curious if something like that would keep the motor cool and cost less watts? That’s the thing, keep the motor cool, may not be enough air.
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Post by Drummond Island Rocks on Dec 4, 2019 7:01:00 GMT -5
Came across this the other day. I assume the fan blade is put on backwards to blow air on the motor Chuck
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jamesp
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Post by jamesp on Dec 4, 2019 7:08:50 GMT -5
At work today I saw a motor like this and noticed it has a separate fan for cooling the air over motor. Between the motor and blower housing is a small shaft mounted axial fan blade. Just curious if something like that would keep the motor cool and cost less watts? That’s the thing, keep the motor coil, may not be enough air. How the designer intended to cool an air-over motor that turns such a slow 225 rpm has been a mystery from the start. Whether it has it's own shaft mounted fan blade or the big fan it is intended for. What the heck kind of fan turns 225 rpm ? And how does it have enough flow to cool the motor at such a slow speed ? The only conclusion I could arrive at is that this fan must have been used as a ventilator in a library or an office space where fan noise had to be extremly low. In watching the video of the shaft speed it can be seen how incredibly slow this thing turns. No answers to how they cooled it. By gosh it is cooled now. A 2800 rpm fan is blasting it ! The additional .2 amps is not much amps in the total scheme of amp usage for most tumblers. I plan on turning 20 to 40 pounds with this unit. Factory made 40 pound units usually use a 1/3 hp motor(.33 hp as compared to my .083 hp main motor + .017 hp fan = 1/10 hp). That equates to 330% more horsepower and certainly more amps but not a whole 330% more amps would be actually used. It is similar to a 4 cylinder with a turbo compared to a V8 without a turbo both equal in horsepower. The turbo eats hp to be driven but over time uses less overall fuel. Keep in mind I don't like those big diameter factory barrels, they do require more power to turn. I find they beat up rocks. I use smaller easier to turn 6 inch barrels at much faster speeds. I get faster grind times. But it also requires more power to turn barrels faster... So this tumbler is being designed for what I have found to be the ultimate barrel size/speed set up which happens to require less horsepower.
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jamesp
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Post by jamesp on Dec 4, 2019 7:20:41 GMT -5
Came across this the other day. I assume the fan blade is put on backwards to blow air on the motor Chuck That looks to be a 1200 to 1700 rpm motor Chuck. At that speed the shaft mounted fan should be turning plenty fast enough to cool the motor. This crazy 225 rpm motor is incredibly slow. Sure seems too slow to have a shaft mount fan to cool it. It was apparent before I purchased these air-over 225's I would have to have an external fan. Is that guy still selling those POS tumblers ? I bought one of his thin wall 8 inch barrels like 10 years ago. This is what happened after 3 months running SiC 46: Funny thing, he said to speed the barrel up to 60 rpm to reduce slippage of the rocks against the barrel which was wearing the barrel out prematurly. This struck me odd - this slippage... Because of that crooked joker I started experimenting with higher speeds and smaller 6 inch barrels that had no 'slippage'.
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oregon
has rocks in the head
gem lap trim saw
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Post by oregon on Dec 27, 2019 19:56:54 GMT -5
Came across this the other day. I assume the fan blade is put on backwards to blow air on the motor Chuck That looks to be a 1200 to 1700 rpm motor Chuck. At that speed the shaft mounted fan should be turning plenty fast enough to cool the motor. This crazy 225 rpm motor is incredibly slow. Sure seems too slow to have a shaft mount fan to cool it. It was apparent before I purchased these air-over 225's I would have to have an external fan. that motor looks sealed on the rear as well?
Any update on the slow motor tumbler - been away, don't see any new threads?
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jamesp
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Post by jamesp on Dec 28, 2019 8:28:59 GMT -5
That looks to be a 1200 to 1700 rpm motor Chuck. At that speed the shaft mounted fan should be turning plenty fast enough to cool the motor. This crazy 225 rpm motor is incredibly slow. Sure seems too slow to have a shaft mount fan to cool it. It was apparent before I purchased these air-over 225's I would have to have an external fan. that motor looks sealed on the rear as well? Any update on the slow motor tumbler - been away, don't see any new threads?
Ha, the neighborhood meth addict stole my package of bearings out of the mailbox. His aunt called and said she found it in his bedroom. Along with my box of new bank checks. Postal investigator working on him now. AND found out he has a warrant in Augusta, GA. He he, the Augusta police now know where he is living now, it won't be long - good riddance ! Just need to order two shaft connection pulleys and build is on oregon. Thanks for inquiring.
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