Keeping water out of bearings on a TEFC motor
Keeping water out of bearings on a TEFC motor
(OP)
When the motors, in a dirty atmosphere are cleaned with high pressure water, water gets into the bearings, causing them to fail.
I think the bearings are the weak link, rather than the motor frame joints.
I am looking for a bearing configuration which will prevent water contamination and damage.
I think the bearings are the weak link, rather than the motor frame joints.
I am looking for a bearing configuration which will prevent water contamination and damage.





RE: Keeping water out of bearings on a TEFC motor
There are a variety of sealing configurations offered. Sealing of the bearing itself as well as sealing of the enclosure.
Ex-member jOmega sent me an e-mail on this exact subject. I'll try to forward the info when I get home.
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RE: Keeping water out of bearings on a TEFC motor
Have you looked at labyrinth seals or motors equiped that way?
RE: Keeping water out of bearings on a TEFC motor
Ex-member jOmega ? Why ?
kumar
RE: Keeping water out of bearings on a TEFC motor
http://www.ryko.com/Italy/contour%20manual.pdf
for:
Waterproof bearings
http://www.smbbearings.com/smbapplications.htm
for:
Waterproof lubricants
RE: Keeping water out of bearings on a TEFC motor
He left for some personal reasons.
He has a web page at:
www.ticon.net/~jomega
The e-mail address at that web-page is a little different than the one he uses to correspond with me. I have e-mailed his address to you kumar. It probably wouldn't be a good idea for me to post it here on the board.
His advice to me when I asked a similar question:
"For motors in outdoor service, DC, Squirrel-Cage, WR, Synchronous, etc; I've always spec'd sealed bearings or IMPRO seals for the bearings. I don't like WP class enclosures..and prefer TEFC or TENV with thermostatically controlled space heaters. The extra cost is well justified in downtime and maintenance savings."
So mostly I think it amounts to specing sealed bearings. If it's an existing motor, with some effort the bearings can be replaced with sealed bearings (with a little evaluation to ensure they won't overheat).
I have seen writeup of many other features used for sealing the clearance between shaft and housing. Forsheda V-ring etc. Sorry I don't have much more info. For new motor I'm sure distributor would be helpful.
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RE: Keeping water out of bearings on a TEFC motor
Bimal K. Bose "Modern Power Electronics and AC Drives," Prentice Hall PTR, 2002
to continue with the topic.
RE: Keeping water out of bearings on a TEFC motor
Take a closer look at the "cause"!
RTV the joints where the end-bells mate to the stator.
Don't pressure clean the shaft area.
Considered using a stiff brush instead?
RE: Keeping water out of bearings on a TEFC motor
IF your hosing down the motors when there hot the rapid cooling is going suck water into the motor. You can wait untill there cool.
One solution I have seen for this is to pressurize the water case with dry air (better nitrogen if available). Pressurization in the case means a couple of inches of water. It can be expensive to do and weather it's worth it or not depends on the cost of the problems your having now.
RE: Keeping water out of bearings on a TEFC motor
RE: Keeping water out of bearings on a TEFC motor
Visit
http://www.reliance.com/pdf_elements/b507.pdf
for:
Shaft Seal
3.2.1 Two independently-mounted mechanical face type seals shall be provided. The inner and outer seal shall be separated by an oil filled chamber. Double seal (back to back) configurations are not acceptable due to the potential for failure of both seals as a result of lodged solids. Similarly bellows-type and jacketed seal construction is also prohibited.
The oil chamber shall act as a barrier to trap moisture and provide sufficient time for a planned shutdown. The oil shall also provide lubrication to the internal seal.
Standard John Crane Type 2 or equal seals shall be provided. Carbon rotating faces and ceramic stationary faces shall be considered standard. Optional seal construction including Tungsten Carbide, Silicon Carbide
faces and use of Viton elastomers are acceptable alternatives. Viton elastomers are recommended for ambient of 61C and higher.
The outer seal construction shall be designed for easy replacement.
The outer seal assembly will be designed to allow solids and particles to be thrown away from the seal face. Optional stainless steel seal shroud is recommended for slurry applications.
RE: Keeping water out of bearings on a TEFC motor
"Venditori de oleum-vipera non vigere excordis populi"
RE: Keeping water out of bearings on a TEFC motor
made by a company called JM Clipper in Texas. Product called PROTECH Sea, type LS - its rated for IP56 & 66 atmospheres.
Made of Teflon/Graphite material. Works great.
web site is www.jmclipper.com
RE: Keeping water out of bearings on a TEFC motor
RE: Keeping water out of bearings on a TEFC motor
Using sealed bearings would cause the water to go into the windings rather than onto the bearings like they have been doing upto now. And you know what will happen when that happens.
Secondly it is never a good idea to clean a motor with high pressure water, especially when that motor does not have that extra protection. Next time you want one of these motors and want to clean the same way , make sure that you ask for an IP55 degree of protection.
If the manufacturer does not have field conversion sets of seals (which will most probably be the case), then try to use sealed bearings and stuff something to seal the opening between the shaft and the end shield, so that water does not penetrate into the motor (remember to take it out when you again start the motor).
RE: Keeping water out of bearings on a TEFC motor
If the manufacturer does not have field conversion sets of seals (which will most probably be the case), then try to use sealed bearings and stuff something to seal the opening between the shaft and the end shield, so that water does not penetrate into the motor (remember to take it out when you again start the motor)."
Can you please describe the path for water to enter the windings. I am particularly interested in why it gets worse when you add sealed bearings.
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RE: Keeping water out of bearings on a TEFC motor
RE: Keeping water out of bearings on a TEFC motor
Maybe when you use sealed bearings, the presurized water has nowhere to go except between the clearances between the bearings and the end shields of the motor. The sealed bearings might add up to the pressure causing the water to pass around the bearings and reach the overhung of the windings. Remember that the leakage of the water is very small, and if that is accomodated by the bearings then there is not much left to reach the windings.
This is my idea and i have nothing to back it up.
RE: Keeping water out of bearings on a TEFC motor
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