01-27-2021, 10:36 AM (This post was last modified: 01-27-2021, 10:37 AM by ®smpr_fi_mac®.)
So the thirty year old motor started making a terrible racket yesterday. Pulled the fan cover off and spun the motor. I hear no crunchy noises that often accompanies bad bearings, but there is a squeal. I wonder if this is the brake mechanism. I hope so; I can likely fix that easily. Pulling the bearings would be a bear on this thing since it's already up. My RAS recently had the same problem: I thought a bearing was bad. Instead, a drop of light oil on the brake mechanism silenced it.
01-27-2021, 10:55 AM (This post was last modified: 01-27-2021, 10:57 AM by TDKPE.)
(01-27-2021, 10:36 AM)®smpr_fi_mac® Wrote: So the thirty year old motor started making a terrible racket yesterday. Pulled the fan cover off and spun the motor. I hear no crunchy noises that often accompanies bad bearings, but there is a squeal. I wonder if this is the brake mechanism. I hope so; I can likely fix that easily. Pulling the bearings would be a bear on this thing since it's already up. My RAS recently had the same problem: I thought a bearing was bad. Instead, a drop of light oil on the brake mechanism silenced it.
That's the centrifugal switch mechanism making that noise, from what I can tell way over here.
Wrap your fingers around the fan in there (or pop the fan off) and pull back the two weights against the springs and see if the noise goes away. If so, no worries. If it really bothers you, you can put some dry lube on the stationary ring they contact to quiet that squeaking.
If that's the cause, you can rest assured that it doesn't squeak when it's up to speed, as those fly weights are out and the mechanism that engages the start capacitor switch has pulled back and is not contacting the switch ring.
Tom
“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
01-28-2021, 10:20 AM (This post was last modified: 01-28-2021, 11:20 AM by ®smpr_fi_mac®.)
The noise occurs while it's running, too, but it's not the squeal you hear at low speed. I need to finish a batch of triangles I'm building (no milling required at this stage) before I start on this. It'll be a few days, but I'll get back with it.
(edit)
I sure hope it's the switch. I'm tired of all these setbacks and really need to get my shop to be productive again!
(01-28-2021, 10:34 PM)®smpr_fi_mac® Wrote: I fear it is a bad bearing. I pulled the switch off and the squeal went away but there another gawdawful racket coming from this same end, I think.
I gotta figure out whether I can change that bearing with the motor still in place; I really don't want to take this thing apart.
At this point, I don’t see where you have much choice. Something is amiss in there, and the only way to get to the bottom of it is to pull it apart.
Sorry. But it’ll be like a new motor when you’re done, and will last for years if you buy good quality bearings. I wouldn’t waste my money on cheap Chinese bearings, as the time and effort involved to replace them down the road is substantial. Motor bearings are small, so good quality bearings won’t actually cost that much anyway.
Tom
“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
So now I have to figure out a path forward. It appears to me that this was not built with the intention of repairs further down the road; I can see no way to attach a puller to remove the impeller.
So, I'm thinking that I lay the blower on its side, motor side down.
Block it up on 2x4's so that the shaft is a couple inches of the floor. Put some foam under the shaft. Remove the four bolts that secure the motor to the blower frame.
From the impeller side, gently rap on the shaft (with a wood dowel to soften the blows) to drive the entire motor down, hopefully sliding the shaft out of the impeller.
From there I can then open the motor and replace the bearings.
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