[Sneap] HVEC GVM Motor Bearings

[Klaus Bahner]

Chris,
 
Although bearing quality has an influence on the GVM output signal, it never
occured to me to use special precision bearings. Those cited SKF bearings
are garden-variety bearings as stocked in virtual any (industrial) hardware
store. Price tage is a few dollars/euros for each in single quantitites. 
In my opinion speed variations of the motor, e.g. due to changing gas loads
and temperature effects, have a much, much greater effect on GVM stability
than a few microns play in the bearings. In our case I can't see any reason
to use 160$ on a super precision bearing.
 
Klaus 
 
 
 


  _____  

From: sneap-bounces at tunl.duke.edu [mailto:sneap-bounces at tunl.duke.edu] On
Behalf Of Chris Westerfeldt
Sent: 20. august 2007 14:53
To: Symposium of Northeastern Accelerator Personnel
Subject: Re: [Sneap] HVEC GVM Motor Bearings


Thanks Klaus,
    This is indeed the dimensions of our bearings.  The ones we removed last
were Barden 38FF and 
KSK WCB7038 bearings.  Barden recommends their 79K3G76 to replace the old
38FF.  These run about $160 each and I questions whether they need to be
super precision bearings.  I haven't found the specifications for the KSK
bearing to compare.  
Regards,
- Chris
-- 

Chris R. Westerfeldt
Research Scientist / T.U.N.L. Radiation Safety Manager
Duke University Physics Department & 
Triangle Universities Nuclear Laboratory
Science Drive, Box 90308
Durham, NC  27708-0308
Tel: (919) 660-2600        
Fax: (919) 660-2634
Email: Cwest at Tunl.Duke.Edu



From: Klaus Bahner <kgb at phys.au.dk>
Reply-To: Symposium of Northeastern Accelerator Personnel
<sneap at tunl.duke.edu>
Date: Mon, 20 Aug 2007 14:31:33 +0200
To: 'Symposium of Northeastern Accelerator Personnel' <sneap at tunl.duke.edu>
Subject: Re: [Sneap] HVEC GVM Motor Bearings
Chris,

I'm not sure whether we are talking about the same motor, but for what it is
worth I use the
608 series bearings, this is bearings with an inner diameter  of 8mm, outer
diameter of 22mm and and a depth of 7 mm.
To be specific I use SKF's 608-2RSH - this is bearings sealed on both sides.
Whether this is just coincidence or whether SKF's bearings are superior in
this aaplications, I don't know, but after a one bearing failure and
frequently required bearing changes in the past when using other makes, I
find that the SKF bearings run troublefree and last very long.

Cheers,
Klaus

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