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Old 5th February 2013, 01:54 AM   #11
kevinkr is offline kevinkr  United States
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This may help: Precession - Wikipedia, the free encyclopedia
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Old 5th February 2013, 02:00 AM   #12
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Originally Posted by kevinkr View Post
I've had a quick look at the basic principles in the link & it still makes me think that precession is more likely with my belts at the bottom than at the top in line with the ball at the top of the bearing??? HELP before my little brain explodes!!!
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Old 5th February 2013, 02:01 AM   #13
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run it where motor torque is lowest ad measure with current meter..

you would be surprise how much little "engineering" goes into something as critical as a turntable bearing..
It al has to do with rotational center of mass of the platter with record and all installed and needle drag how the bearing is loaded there will be a sweet spot in any sleeve thrust arrangement
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Old 5th February 2013, 02:06 AM   #14
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Originally Posted by IMSTOOPID View Post
run it where motor torque is lowest ad measure with current meter..

you would be surprise how much little "engineering" goes into something as critical as a turntable bearing..
It al has to do with rotational center of mass of the platter with record and all installed and needle drag how the bearing is loaded there will be a sweet spot in any sleeve thrust arrangement
It's a DC motor with speed control & although I didn't use a meter, it definitely used less power to run the belts at the top. I had to dial it down, maybe a quarter turn. To give you an idea, it's only a 3 quarter turn of the dial to go from 33.3 to 45 rpm.
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Old 5th February 2013, 02:11 AM   #15
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Originally Posted by Arckivio View Post
It's a DC motor with speed control & although I didn't use a meter, it definitely used less power to run the belts at the top. I had to dial it down, maybe a quarter turn. To give you an idea, it's only a 3 quarter turn of the dial to go from 33.3 to 45 rpm.
Is there any kind of feedback to the motor to maintain the correct speed?

jeff
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Old 5th February 2013, 02:14 AM   #16
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Is there any kind of feedback to the motor to maintain the correct speed?

jeff
I did take the motor apart but I haven't really got the technical knowledge to answer that. As far as I can tell, there seemed to be just a resistor & what looked like a capacitor & I'm not even sure if I've got them right. Not a lot in the motor housing really.
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Old 5th February 2013, 02:15 AM   #17
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Belt location on the platter cannot influance motor load in any way,unless the diameter of the platter changes from top to bottom. but then speed will change too.
The only issue i see here is centering the force applied by the belt with the center of the bearing so the bearing will be loaded evenly, so wear will be minimal.
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Old 5th February 2013, 02:17 AM   #18
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that is why u measure motor current.. duh.. evenly loaded bearing turns easier less load.
but u need album clamp mat and arm load on unit
position of load does effect the bearing load in a sleeve n thrust bearing as i said before.

Last edited by IMSTOOPID; 5th February 2013 at 02:19 AM. Reason: spell
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Old 5th February 2013, 02:18 AM   #19
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Belt location on the platter cannot influance motor load in any way,unless the diameter of the platter changes from top to bottom. but then speed will change too.
The only issue i see here is centering the force applied by the belt with the center of the bearing so the bearing will be loaded evenly, so wear will be minimal.
Surely it would load the motor more if it's pulling the bottom of the platter but isn't at the top. At the bottom its putting more force metal to metal but isn't at the top I think.
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Old 5th February 2013, 02:23 AM   #20
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Originally Posted by IMSTOOPID View Post
that is why u measure motor current.. duh.. evenly loaded bearing turns easier less load.
but u need album clamp mat and arm load on unit
position of load does effect the bearing load in a sleeve n thrust bearing as i said before.
I will try it with a meter as even I can do that, but it I think it will measure lower current needed with belts at the top as it seems to need less power on the dial. By the way, good idea. Thanks
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