Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Turntable bearing question.
Turntable bearing question.
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th February 2013, 12:54 AM   #11
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Turntable bearing question.
This may help: Precession - Wikipedia, the free encyclopedia
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 5th February 2013, 01:00 AM   #12
Arckivio is offline Arckivio  United Kingdom
diyAudio Member
 
Join Date: Dec 2012
Quote:
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!!!
  Reply With Quote
Old 5th February 2013, 01:01 AM   #13
IMSTOOPID is offline IMSTOOPID  United States
diyAudio Member
 
Join Date: Feb 2007
Location: HICKSVILLE TN
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
  Reply With Quote
Old 5th February 2013, 01:06 AM   #14
Arckivio is offline Arckivio  United Kingdom
diyAudio Member
 
Join Date: Dec 2012
Quote:
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.
  Reply With Quote
Old 5th February 2013, 01:11 AM   #15
vinylkid58 is offline vinylkid58  Canada
diyAudio Member
 
vinylkid58's Avatar
 
Join Date: May 2005
Location: Victoria, B.C.
Quote:
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
  Reply With Quote
Old 5th February 2013, 01:14 AM   #16
Arckivio is offline Arckivio  United Kingdom
diyAudio Member
 
Join Date: Dec 2012
Quote:
Originally Posted by vinylkid58 View Post
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.
  Reply With Quote
Old 5th February 2013, 01:15 AM   #17
BenY is offline BenY
diyAudio Member
 
Join Date: Jul 2002
Location: ISRAEL
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.
  Reply With Quote
Old 5th February 2013, 01:17 AM   #18
IMSTOOPID is offline IMSTOOPID  United States
diyAudio Member
 
Join Date: Feb 2007
Location: HICKSVILLE TN
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 01:19 AM. Reason: spell
  Reply With Quote
Old 5th February 2013, 01:18 AM   #19
Arckivio is offline Arckivio  United Kingdom
diyAudio Member
 
Join Date: Dec 2012
Quote:
Originally Posted by BenY View Post
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.
  Reply With Quote
Old 5th February 2013, 01:23 AM   #20
Arckivio is offline Arckivio  United Kingdom
diyAudio Member
 
Join Date: Dec 2012
Quote:
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
  Reply With Quote

Reply


Turntable bearing question.Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Other bearing for turntable use? Zero One Analogue Source 9 8th November 2017 05:22 AM
Bearing for turntable ste Analogue Source 2 2nd August 2010 06:26 PM
Turntable bearing question dod996 Analogue Source 15 4th June 2010 04:49 AM
Turntable bearing Tee-Rex Analogue Source 3 5th May 2005 06:55 PM
turntable bearing design sc351cobra Analogue Source 1 24th March 2005 10:30 AM


New To Site? Need Help?

All times are GMT. The time now is 12:55 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki