Condenser fan movement

[seanf]

BAC condenser fan with axial movement, looks like the white U channel pillow block support is flexing, the top of the block exaggerates the movement but the block seems to be fixed securly to the support.

Think it was 35Hz,
https://www.flickr.com/photos/s34n/51860341026/in/photostream/

About 15Hz,
https://www.flickr.com/photos/s34n/51860686009/in/photostream/

[seanf]

Anyone come across this problem of the U channel flexing? Not so sure its a design feature.

[RANGER1]

seanf,
Have bearings recently been replaced?
How does drive end look, belt alignment, pulley?
Are they being greased regularly, no signs of any greasing, normally run nylon tube out to where more accessible to grease.
Have you tried higher speed like 50 or 60Hz to see if bigger issue.

[seanf]

The bearings were replaced that day by others.
Ran out of time to check everything properly, but drive end bearing by eye dosnt seem to move noticably, pulley didnt look bad but again not checked properly.
I dont think the customer wants to pay for the extension tubes.
Like your saying, alignment of the pulleys to be checked as a start for whats causing the movement, but wasnt expecting to see the support U channel flex, maybe the axial forces are just higher than designed for.

Cheers

[RANGER1]

It’s one of those things, the people who fitted bearings would know how things were when fitting bearings, so can be hard coming in later without working on it.
The people who did it should be asked to come back & check everything & put their name on it.
- Is shaft running true, could have been damaged when taking off old bearings.
- Are bearings free in pillar block to self align

- no sign of greasing bearings

If you run up to full speed, maybe it answers question of something seriously wrong.

[RANGER1]

It’s one of those things, the people who fitted bearings would know how things were when fitting bearings, so can be hard coming in later without working on it.
The people who did it should be asked to come back & check everything & put their name on it.
- Is shaft running true, could have been damaged when taking off old bearings.
- Are bearings free in pillar block to self align

- no sign of greasing bearings

[seanf]

Ran it at full speed, only thing that seemed to stand out was the axial movement.
Not sure on the pillow block/bearing set up, the bearings came in a BAC box so assuming its a standard set from them.
Asked about that, and the fitters said they come with an initial charge of grease.

Still to find out what the original fault was for the bearings to be changed.

I did look at the old bearings that were cut off, and the larger drive end bearing had three of the ball bearings with noticable wear markings that lined up with the edge of the cage. The markings were hidden untill the ball, with a bit of resistance, was rotated. Otherwise it was only small imperfections on the races, couldnt tell if they were worn down or not. The rest of the ball bearings were smooth and seemed to be held well by the cage.

https://www.flickr.com/photos/s34n/51863477358/in/dateposted-public/

The axial movement may have been a problem before the bearings were changed.

[seanf]

Pulleys were out by about 3/8". With alignment closer the belt noise reduced alot and axial movement seems to be reduced.